Network Working Group                                         J. Quittek
Request for Comments: 5102                                           NEC
Category: Standards Track                                      S. Bryant
                                                               B. Claise
                                                               P. Aitken
                                                     Cisco Systems, Inc.
                                                                J. Meyer
                                                                  PayPal
                                                           December 2007

            Information Model for IP Flow Information Export

Status of This Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Abstract

   This memo defines an information model for the IP Flow Information
   eXport (IPFIX) protocol.  It is used by the IPFIX protocol for
   encoding measured traffic information and information related to the
   traffic Observation Point, the traffic Metering Process, and the
   Exporting Process.  Although developed for the IPFIX protocol, the
   model is defined in an open way that easily allows using it in other
   protocols, interfaces, and applications.

Table of Contents

   1. Introduction ....................................................6
   2. Properties of IPFIX Protocol Information Elements ...............7
      2.1. Information Elements Specification Template ................7
      2.2. Scope of Information Elements ..............................9
      2.3. Naming Conventions for Information Elements ................9
   3. Type Space .....................................................10
      3.1. Abstract Data Types .......................................10
           3.1.1. unsigned8 ..........................................10
           3.1.2. unsigned16 .........................................11
           3.1.3. unsigned32 .........................................11
           3.1.4. unsigned64 .........................................11
           3.1.5. signed8 ............................................11
           3.1.6. signed16 ...........................................11
           3.1.7. signed32 ...........................................11
           3.1.8. signed64 ...........................................11
           3.1.9. float32 ............................................11
           3.1.10. float64 ...........................................11
           3.1.11. boolean ...........................................12
           3.1.12. macAddress ........................................12
           3.1.13. octetArray ........................................12
           3.1.14. string ............................................12
           3.1.15. dateTimeSeconds ...................................12
           3.1.16. dateTimeMilliseconds ..............................12
           3.1.17. dateTimeMicroseconds ..............................12
           3.1.18. dateTimeNanoseconds ...............................13
           3.1.19. ipv4Address .......................................13
           3.1.20. ipv6Address .......................................13
      3.2. Data Type Semantics .......................................13
           3.2.1. quantity ...........................................13
           3.2.2. totalCounter .......................................13
           3.2.3. deltaCounter .......................................14
           3.2.4. identifier .........................................14
           3.2.5. flags ..............................................14
   4. Information Element Identifiers ................................14
   5. Information Elements ...........................................18
      5.1. Identifiers ...............................................19
           5.1.1. lineCardId .........................................20
           5.1.2. portId .............................................20
           5.1.3. ingressInterface ...................................20
           5.1.4. egressInterface ....................................21
           5.1.5. meteringProcessId ..................................21
           5.1.6. exportingProcessId .................................21
           5.1.7. flowId .............................................22
           5.1.8. templateId .........................................22
           5.1.9. observationDomainId ................................22
           5.1.10. observationPointId ................................23
           5.1.11. commonPropertiesId ................................23
      5.2. Metering and Exporting Process Configuration ..............23
           5.2.1. exporterIPv4Address ................................24
           5.2.2. exporterIPv6Address ................................24
           5.2.3. exporterTransportPort ..............................24
           5.2.4. collectorIPv4Address ...............................25
           5.2.5. collectorIPv6Address ...............................25
           5.2.6. collectorInterface .................................25
           5.2.7. collectorProtocolVersion ...........................26
           5.2.8. collectorTransportProtocol .........................26
           5.2.9. collectorTransportPort .............................27
           5.2.10. flowKeyIndicator ..................................27
      5.3. Metering and Exporting Process Statistics .................28
           5.3.1. exportedMessageTotalCount ..........................28
           5.3.2. exportedOctetTotalCount ............................28
           5.3.3. exportedFlowRecordTotalCount .......................29
           5.3.4. observedFlowTotalCount .............................29
           5.3.5. ignoredPacketTotalCount ............................29
           5.3.6. ignoredOctetTotalCount .............................30
           5.3.7. notSentFlowTotalCount ..............................30
           5.3.8. notSentPacketTotalCount ............................30
           5.3.9. notSentOctetTotalCount .............................31
      5.4. IP Header Fields ..........................................31
           5.4.1. ipVersion ..........................................31
           5.4.2. sourceIPv4Address ..................................32
           5.4.3. sourceIPv6Address ..................................32
           5.4.4. sourceIPv4PrefixLength .............................32
           5.4.5. sourceIPv6PrefixLength .............................33
           5.4.6. sourceIPv4Prefix ...................................33
           5.4.7. sourceIPv6Prefix ...................................33
           5.4.8. destinationIPv4Address .............................33
           5.4.9. destinationIPv6Address .............................34
           5.4.10. destinationIPv4PrefixLength .......................34
           5.4.11. destinationIPv6PrefixLength .......................34
           5.4.12. destinationIPv4Prefix .............................34
           5.4.13. destinationIPv6Prefix .............................35
           5.4.14. ipTTL .............................................35
           5.4.15. protocolIdentifier ................................35
           5.4.16. nextHeaderIPv6 ....................................36
           5.4.17. ipDiffServCodePoint ...............................36
           5.4.18. ipPrecedence ......................................36
           5.4.19. ipClassOfService ..................................37
           5.4.20. postIpClassOfService ..............................37
           5.4.21. flowLabelIPv6 .....................................38
           5.4.22. isMulticast .......................................38
           5.4.23. fragmentIdentification ............................39
           5.4.24. fragmentOffset ....................................39
           5.4.25. fragmentFlags .....................................39
           5.4.26. ipHeaderLength ....................................40
           5.4.27. ipv4IHL ...........................................40
           5.4.28. totalLengthIPv4 ...................................41
           5.4.29. ipTotalLength .....................................41
           5.4.30. payloadLengthIPv6 .................................41
      5.5. Transport Header Fields ...................................42
           5.5.1. sourceTransportPort ................................42
           5.5.2. destinationTransportPort ...........................42
           5.5.3. udpSourcePort ......................................43
           5.5.4. udpDestinationPort .................................43
           5.5.5. udpMessageLength ...................................43
           5.5.6. tcpSourcePort ......................................44
           5.5.7. tcpDestinationPort .................................44
           5.5.8. tcpSequenceNumber ..................................44
           5.5.9. tcpAcknowledgementNumber ...........................44
           5.5.10. tcpWindowSize .....................................45
           5.5.11. tcpWindowScale ....................................45
           5.5.12. tcpUrgentPointer ..................................45
           5.5.13. tcpHeaderLength ...................................45
           5.5.14. icmpTypeCodeIPv4 ..................................46
           5.5.15. icmpTypeIPv4 ......................................46
           5.5.16. icmpCodeIPv4 ......................................46
           5.5.17. icmpTypeCodeIPv6 ..................................46
           5.5.18. icmpTypeIPv6 ......................................47
           5.5.19. icmpCodeIPv6 ......................................47
           5.5.20. igmpType ..........................................47
      5.6. Sub-IP Header Fields ......................................48
           5.6.1. sourceMacAddress ...................................48
           5.6.2. postSourceMacAddress ...............................48
           5.6.3. vlanId .............................................49
           5.6.4. postVlanId .........................................49
           5.6.5. destinationMacAddress ..............................49
           5.6.6. postDestinationMacAddress ..........................49
           5.6.7. wlanChannelId ......................................50
           5.6.8. wlanSSID ...........................................50
           5.6.9. mplsTopLabelTTL ....................................50
           5.6.10. mplsTopLabelExp ...................................51
           5.6.11. postMplsTopLabelExp ...............................51
           5.6.12. mplsLabelStackDepth ...............................51
           5.6.13. mplsLabelStackLength ..............................52
           5.6.14. mplsPayloadLength .................................52
           5.6.15. mplsTopLabelStackSection ..........................52
           5.6.16. mplsLabelStackSection2 ............................53
           5.6.17. mplsLabelStackSection3 ............................53
           5.6.18. mplsLabelStackSection4 ............................53
           5.6.19. mplsLabelStackSection5 ............................54
           5.6.20. mplsLabelStackSection6 ............................54
           5.6.21. mplsLabelStackSection7 ............................54
           5.6.22. mplsLabelStackSection8 ............................55
           5.6.23. mplsLabelStackSection9 ............................55
           5.6.24. mplsLabelStackSection10 ...........................55
      5.7. Derived Packet Properties .................................56
           5.7.1. ipPayloadLength ....................................56
           5.7.2. ipNextHopIPv4Address ...............................56
           5.7.3. ipNextHopIPv6Address ...............................57
           5.7.4. bgpSourceAsNumber ..................................57
           5.7.5. bgpDestinationAsNumber .............................57
           5.7.6. bgpNextAdjacentAsNumber ............................57
           5.7.7. bgpPrevAdjacentAsNumber ............................58
           5.7.8. bgpNextHopIPv4Address ..............................58
           5.7.9. bgpNextHopIPv6Address ..............................58
           5.7.10. mplsTopLabelType ..................................59
           5.7.11. mplsTopLabelIPv4Address ...........................59
           5.7.12. mplsTopLabelIPv6Address ...........................60
           5.7.13. mplsVpnRouteDistinguisher .........................60
      5.8. Min/Max Flow Properties ...................................61
           5.8.1. minimumIpTotalLength ...............................61
           5.8.2. maximumIpTotalLength ...............................61
           5.8.3. minimumTTL .........................................61
           5.8.4. maximumTTL .........................................62
           5.8.5. ipv4Options ........................................62
           5.8.6. ipv6ExtensionHeaders ...............................64
           5.8.7. tcpControlBits .....................................65
           5.8.8. tcpOptions .........................................66
      5.9. Flow Timestamps ...........................................67
           5.9.1. flowStartSeconds ...................................67
           5.9.2. flowEndSeconds .....................................68
           5.9.3. flowStartMilliseconds ..............................68
           5.9.4. flowEndMilliseconds ................................68
           5.9.5. flowStartMicroseconds ..............................68
           5.9.6. flowEndMicroseconds ................................68
           5.9.7. flowStartNanoseconds ...............................69
           5.9.8. flowEndNanoseconds .................................69
           5.9.9. flowStartDeltaMicroseconds .........................69
           5.9.10. flowEndDeltaMicroseconds ..........................69
           5.9.11. systemInitTimeMilliseconds ........................70
           5.9.12. flowStartSysUpTime ................................70
           5.9.13. flowEndSysUpTime ..................................70
      5.10. Per-Flow Counters ........................................70
           5.10.1. octetDeltaCount ...................................71
           5.10.2. postOctetDeltaCount ...............................71
           5.10.3. octetDeltaSumOfSquares ............................72
           5.10.4. octetTotalCount ...................................72
           5.10.5. postOctetTotalCount ...............................72
           5.10.6. octetTotalSumOfSquares ............................72
           5.10.7. packetDeltaCount ..................................73
           5.10.8. postPacketDeltaCount ..............................73
           5.10.9. packetTotalCount ..................................73
           5.10.10. postPacketTotalCount .............................74
           5.10.11. droppedOctetDeltaCount ...........................74
           5.10.12. droppedPacketDeltaCount ..........................74
           5.10.13. droppedOctetTotalCount ...........................74
           5.10.14. droppedPacketTotalCount ..........................75
           5.10.15. postMCastPacketDeltaCount ........................75
           5.10.16. postMCastOctetDeltaCount .........................75
           5.10.17. postMCastPacketTotalCount ........................76
           5.10.18. postMCastOctetTotalCount .........................76
           5.10.19. tcpSynTotalCount .................................76
           5.10.20. tcpFinTotalCount .................................77
           5.10.21. tcpRstTotalCount .................................77
           5.10.22. tcpPshTotalCount .................................77
           5.10.23. tcpAckTotalCount .................................78
           5.10.24. tcpUrgTotalCount .................................78
      5.11. Miscellaneous Flow Properties ............................78
           5.11.1. flowActiveTimeout .................................79
           5.11.2. flowIdleTimeout ...................................79
           5.11.3. flowEndReason .....................................79
           5.11.4. flowDurationMilliseconds ..........................80
           5.11.5. flowDurationMicroseconds ..........................80
           5.11.6. flowDirection .....................................80
      5.12. Padding ..................................................80
           5.12.1. paddingOctets .....................................81
   6. Extending the Information Model ................................81
   7. IANA Considerations ............................................82
      7.1. IPFIX Information Elements ................................82
      7.2. MPLS Label Type Identifier ................................82
      7.3. XML Namespace and Schema ..................................83
   8. Security Considerations ........................................83
   9. Acknowledgements ...............................................84
   10. References ....................................................84
      10.1. Normative References .....................................84
      10.2. Informative References ...................................84
   Appendix A. XML Specification of IPFIX Information Elements .......89
   Appendix B. XML Specification of Abstract Data Types .............158

1.  Introduction

   The IP Flow Information eXport (IPFIX) protocol serves for
   transmitting information related to measured IP traffic over the
   Internet.  The protocol specification in [RFC5101] defines how
   Information Elements are transmitted.  For Information Elements, it
   specifies the encoding of a set of basic data types.  However, the
   list of Information Elements that can be transmitted by the protocol,
   such as Flow attributes (source IP address, number of packets, etc.)
   and information about the Metering and Exporting Process (packet
   Observation Point, sampling rate, Flow timeout interval, etc.), is
   not specified in [RFC5101].

   This document complements the IPFIX protocol specification by
   providing the IPFIX information model.  IPFIX-specific terminology
   used in this document is defined in Section 2 of [RFC5101].  As in
   [RFC5101], these IPFIX-specific terms have the first letter of a word
   capitalized when used in this document.

   The use of the term 'information model' is not fully in line with the
   definition of this term in [RFC3444].  The IPFIX information model
   does not specify relationships between Information Elements, but also
   it does not specify a concrete encoding of Information Elements.
   Besides the encoding used by the IPFIX protocol, other encodings of
   IPFIX Information Elements can be applied, for example, XML-based
   encodings.

   The main part of this document is Section 5, which defines the
   (extensible) list of Information Elements to be transmitted by the
   IPFIX protocol.  Section 2 defines a template for specifying IPFIX
   Information Elements in Section 5.  Section 3 defines the set of
   abstract data types that are available for IPFIX Information
   Elements.  Section 6 discusses extensibility of the IPFIX information
   model.

   The main bodies of Sections 2, 3, and 5 were generated from XML
   documents.  The XML-based specification of template, abstract data
   types, and IPFIX Information Elements can be used for automatically
   checking syntactical correctness of the specification of IPFIX
   Information Elements.  It can further be used for generating IPFIX
   protocol implementation code that deals with processing IPFIX
   Information Elements.  Also, code for applications that further
   process traffic information transmitted via the IPFIX protocol can be
   generated with the XML specification of IPFIX Information Elements.

   For that reason, the XML document that served as a source for Section
   5 and the XML schema that served as source for Sections 2 and 3 are
   attached to this document in Appendices A and B.

   Note that although partially generated from the attached XML
   documents, the main body of this document is normative while the
   appendices are informational.

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

2.  Properties of IPFIX Protocol Information Elements

2.1.  Information Elements Specification Template

   Information in messages of the IPFIX protocol is modeled in terms of
   Information Elements of the IPFIX information model.  IPFIX
   Information Elements are specified in Section 5.  For specifying
   these Information Elements, a template is used that is described
   below.

   All Information Elements specified for the IPFIX protocol either in
   this document or by any future extension MUST have the following
   properties defined:

   name - A unique and meaningful name for the Information Element.

   elementId - A numeric identifier of the Information Element.  If this
      identifier is used without an enterprise identifier (see [RFC5101]
      and enterpriseId below), then it is globally unique and the list
      of allowed values is administered by IANA.  It is used for compact
      identification of an Information Element when encoding Templates
      in the protocol.

   description - The semantics of this Information Element.  Describes
      how this Information Element is derived from the Flow or other
      information available to the observer.

   dataType - One of the types listed in Section 3.1 of this document or
      in a future extension of the information model.  The type space
      for attributes is constrained to facilitate implementation.  The
      existing type space does however encompass most basic types used
      in modern programming languages, as well as some derived types
      (such as ipv4Address) that are common to this domain and useful to
      distinguish.

   status - The status of the specification of this Information Element.
      Allowed values are 'current', 'deprecated', and 'obsolete'.

   Enterprise-specific Information Elements MUST have the following
   property defined:

   enterpriseId - Enterprises may wish to define Information Elements
      without registering them with IANA, for example, for
      enterprise-internal purposes.  For such Information Elements, the
      Information Element identifier described above is not sufficient
      when the Information Element is used outside the enterprise.  If
      specifications of enterprise-specific Information Elements are
      made public and/or if enterprise-specific identifiers are used by
      the IPFIX protocol outside the enterprise, then the
      enterprise-specific identifier MUST be made globally unique by
      combining it with an enterprise identifier.  Valid values for the
      enterpriseId are defined by IANA as Structure of Management
      Information (SMI) network management private enterprise codes.
      They are defined at http://www.iana.org/assignments/enterprise-
      numbers.

   All Information Elements specified for the IPFIX protocol either in
   this document or by any future extension MAY have the following
   properties defined:

   dataTypeSemantics - The integral types may be qualified by additional
      semantic details.  Valid values for the data type semantics are
      specified in Section 3.2 of this document or in a future extension
      of the information model.

   units - If the Information Element is a measure of some kind, the
      units identify what the measure is.

   range - Some Information Elements may only be able to take on a
      restricted set of values that can be expressed as a range (e.g., 0
      through 511 inclusive).  If this is the case, the valid inclusive
      range should be specified.

   reference - Identifies additional specifications that more precisely
      define this item or provide additional context for its use.

2.2.  Scope of Information Elements

   By default, most Information Elements have a scope specified in their
   definitions.

   o  The Information Elements defined in Sections 5.2 and 5.3 have a
      default of "a specific Metering Process" or of "a specific
      Exporting Process", respectively.

   o  The Information Elements defined in Sections 5.4-5.11 have a scope
      of "a specific Flow".

   Within Data Records defined by Option Templates, the IPFIX protocol
   allows further limiting of the Information Element scope.  The new
   scope is specified by one or more scope fields and defined as the
   combination of all specified scope values; see Section 3.4.2.1 on
   IPFIX scopes in [RFC5101].

2.3.  Naming Conventions for Information Elements

    The following naming conventions were used for naming Information
    Elements in this document.  It is recommended that extensions of the
    model use the same conventions.

   o  Names of Information Elements should be descriptive.

   o  Names of Information Elements that are not enterprise-specific
      MUST be unique within the IPFIX information model.
      Enterprise-specific Information Elements SHOULD be prefixed with a
      vendor name.

   o  Names of Information Elements start with non-capitalized letters.

   o  Composed names use capital letters for the first letter of each
      component (except for the first one).  All other letters are
      non-capitalized, even for acronyms.  Exceptions are made for
      acronyms containing non-capitalized letter, such as 'IPv4' and
      'IPv6'.  Examples are sourceMacAddress and destinationIPv4Address.

   o  Middleboxes [RFC3234] may change Flow properties, such as the
      Differentiated Service Code Point (DSCP) value or the source IP
      address.  If an IPFIX Observation Point is located in the path of
      a Flow before one or more middleboxes that potentially modify
      packets of the Flow, then it may be desirable to also report Flow
      properties after the modification performed by the middleboxes.
      An example is an Observation Point before a packet marker changing
      a packet's IPv4 Type of Service (TOS) field that is encoded in
      Information Element classOfServiceIPv4.  Then the value observed
      and reported by Information Element classOfServiceIPv4 is valid at
      the Observation Point, but not after the packet passed the packet
      marker.  For reporting the change value of the TOS field, the
      IPFIX information model uses Information Elements that have a name
      prefix "post", for example, "postClassOfServiceIPv4".  Information
      Elements with prefix "post" report on Flow properties that are not
      necessarily observed at the Observation Point, but which are
      obtained within the Flow's Observation Domain by other means
      considered to be sufficiently reliable, for example, by analyzing
      the packet marker's marking tables.

3.  Type Space

   This section describes the abstract data types that can be used for
   the specification of IPFIX Information Elements in Section 4.
   Section 3.1 describes the set of abstract data types.

   Abstract data types unsigned8, unsigned16, unsigned32, unsigned64,
   signed8, signed16, signed32, and signed64 are integral data types.
   As described in Section 3.2, their data type semantics can be further
   specified, for example, by 'totalCounter', 'deltaCounter',
   'identifier', or 'flags'.

3.1.  Abstract Data Types

   This section describes the set of valid abstract data types of the
   IPFIX information model.  Note that further abstract data types may
   be specified by future extensions of the IPFIX information model.

3.1.1.  unsigned8

   The type "unsigned8" represents a non-negative integer value in the
   range of 0 to 255.

3.1.2.  unsigned16

   The type "unsigned16" represents a non-negative integer value in the
   range of 0 to 65535.

3.1.3.  unsigned32

   The type "unsigned32" represents a non-negative integer value in the
   range of 0 to 4294967295.

3.1.4.  unsigned64

   The type "unsigned64" represents a non-negative integer value in the
   range of 0 to 18446744073709551615.

3.1.5.  signed8

   The type "signed8" represents an integer value in the range of -128
   to 127.

3.1.6.  signed16

   The type "signed16" represents an integer value in the range of
   -32768 to 32767.

3.1.7.  signed32

   The type "signed32" represents an integer value in the range of
   -2147483648 to 2147483647.

3.1.8.  signed64

   The type "signed64" represents an integer value in the range of
   -9223372036854775808 to 9223372036854775807.

3.1.9.  float32

   The type "float32" corresponds to an IEEE single-precision 32-bit
   floating point type as defined in [IEEE.754.1985].

3.1.10.  float64

   The type "float64" corresponds to an IEEE double-precision 64-bit
   floating point type as defined in [IEEE.754.1985].

3.1.11.  boolean

   The type "boolean" represents a binary value.  The only allowed
   values are "true" and "false".

3.1.12.  macAddress

   The type "macAddress" represents a string of 6 octets.

3.1.13.  octetArray

   The type "octetArray" represents a finite-length string of octets.

3.1.14.  string

   The type "string" represents a finite-length string of valid
   characters from the Unicode character encoding set [ISO.10646-
   1.1993].  Unicode allows for ASCII [ISO.646.1991] and many other
   international character sets to be used.

3.1.15.  dateTimeSeconds

   The type "dateTimeSeconds" represents a time value in units of
   seconds based on coordinated universal time (UTC).  The choice of an
   epoch, for example, 00:00 UTC, January 1, 1970, is left to
   corresponding encoding specifications for this type, for example, the
   IPFIX protocol specification.  Leap seconds are excluded.  Note that
   transformation of values might be required between different
   encodings if different epoch values are used.

3.1.16.  dateTimeMilliseconds

   The type "dateTimeMilliseconds" represents a time value in units of
   milliseconds based on coordinated universal time (UTC).  The choice
   of an epoch, for example, 00:00 UTC, January 1, 1970, is left to
   corresponding encoding specifications for this type, for example, the
   IPFIX protocol specification.  Leap seconds are excluded.  Note that
   transformation of values might be required between different
   encodings if different epoch values are used.

3.1.17.  dateTimeMicroseconds

   The type "dateTimeMicroseconds" represents a time value in units of
   microseconds based on coordinated universal time (UTC).  The choice
   of an epoch, for example, 00:00 UTC, January 1, 1970, is left to
   corresponding encoding specifications for this type, for example, the
   IPFIX protocol specification.  Leap seconds are excluded.  Note that
   transformation of values might be required between different
   encodings if different epoch values are used.

3.1.18.  dateTimeNanoseconds

   The type "dateTimeNamoseconds" "dateTimeNanoseconds" represents a time value in units of
   nanoseconds based on coordinated universal time (UTC).  The choice of
   an epoch, for example, 00:00 UTC, January 1, 1970, is left to
   corresponding encoding specifications for this type, for example, the
   IPFIX protocol specification.  Leap seconds are excluded.  Note, that
   transformation of values might be required between different
   encodings if different epoch values are used.

3.1.19.  ipv4Address

   The type "ipv4Address" represents a value of an IPv4 address.

3.1.20.  ipv6Address

   The type "ipv6Address" represents a value of an IPv6 address.

3.2.  Data Type Semantics

   This section describes the set of valid data type semantics of the
   IPFIX information model.  Note that further data type semantics may
   be specified by future extensions of the IPFIX information model.

3.2.1.  quantity

   A quantity value represents a discrete measured value pertaining to
   the record.  This is distinguished from counters that represent an
   ongoing measured value whose "odometer" reading is captured as part
   of a given record.  If no semantic qualifier is given, the
   Information Elements that have an integral data type should behave as
   a quantity.

3.2.2.  totalCounter

   An integral value reporting the value of a counter.  Counters are
   unsigned and wrap back to zero after reaching the limit of the type.
   For example, an unsigned64 with counter semantics will continue to
   increment until reaching the value of 2**64 - 1.  At this point, the
   next increment will wrap its value to zero and continue counting from
   zero.  The semantics of a total counter is similar to the semantics
   of counters used in SNMP, such as Counter32 defined in RFC 2578
   [RFC2578].  The only difference between total counters and counters
   used in SNMP is that the total counters have an initial value of 0.
   A total counter counts independently of the export of its value.

3.2.3.  deltaCounter

   An integral value reporting the value of a counter.  Counters are
   unsigned and wrap back to zero after reaching the limit of the type.
   For example, an unsigned64 with counter semantics will continue to
   increment until reaching the value of 2**64 - 1.  At this point, the
   next increment will wrap its value to zero and continue counting from
   zero.  The semantics of a delta counter is similar to the semantics
   of counters used in SNMP, such as Counter32 defined in RFC 2578
   [RFC2578].  The only difference between delta counters and counters
   used in SNMP is that the delta counters have an initial value of 0.
   A delta counter is reset to 0 each time its value is exported.

3.2.4.  identifier

   An integral value that serves as an identifier.  Specifically,
   mathematical operations on two identifiers (aside from the equality
   operation) are meaningless.  For example, Autonomous System ID 1 *
   Autonomous System ID 2 is meaningless.

3.2.5.  flags

   An integral value that actually represents a set of bit fields.
   Logical operations are appropriate on such values, but not other
   mathematical operations.  Flags should always be of an unsigned type.

4.  Information Element Identifiers

   All Information Elements defined in Section 5 of this document or in
   future extensions of the IPFIX information model have their
   identifiers assigned by IANA.  Their identifiers can be retrieved at
   http://www.iana.org/assignments/ipfix.

   The value of these identifiers is in the range of 1-32767.  Within
   this range, Information Element identifier values in the sub-range of
   1-127 are compatible with field types used by NetFlow version 9
   [RFC3954].

   +---------------------------------+---------------------------------+
   | Range of IANA-assigned          | Description                     |
   | Information Element identifiers |                                 |
   +---------------------------------+---------------------------------+
   | 0                               | Reserved.                       |
   | 1-127                           | Information Element identifiers |
   |                                 | compatible with NetFlow version |
   |                                 | 9 field types [RFC3954].        |
   | 128-32767                       | Further Information Element     |
   |                                 | identifiers.                    |
   +---------------------------------+---------------------------------+

   Enterprise-specific Information Element identifiers have the same
   range of 1-32767, but they are coupled with an additional enterprise
   identifier.

   Enterprise-specific Information Element identifiers can be chosen by
   an enterprise arbitrarily within the range of 1-32767.  The same
   identifier may be assigned by other enterprises for different
   purposes.

   Still, Collecting Processes can distinguish these Information
   Elements because the Information Element identifier is coupled with
   an enterprise identifier.

   Enterprise identifiers MUST be registered as SMI network management
   private enterprise code numbers with IANA.  The registry can be found
   at http://www.iana.org/assignments/enterprise-numbers.

   The following list gives an overview of the Information Element
   identifiers that are specified in Section 5 and are compatible with
   field types used by NetFlow version 9 [RFC3954].

   +----+----------------------------+-------+-------------------------+
   | ID | Name                       |    ID | Name                    |
   +----+----------------------------+-------+-------------------------+
   |  1 | octetDeltaCount            |    43 | RESERVED                |
   |  2 | packetDeltaCount           |    44 | sourceIPv4Prefix        |
   |  3 | RESERVED                   |    45 | destinationIPv4Prefix   |
   |  4 | protocolIdentifier         |    46 | mplsTopLabelType        |
   |  5 | ipClassOfService           |    47 | mplsTopLabelIPv4Address |
   |  6 | tcpControlBits             | 48-51 | RESERVED                |
   |  7 | sourceTransportPort        |    52 | minimumTTL              |
   |  8 | sourceIPv4Address          |    53 | maximumTTL              |
   |  9 | sourceIPv4PrefixLength     |    54 | fragmentIdentification  |
   | 10 | ingressInterface           |    55 | postIpClassOfService    |
   | 11 | destinationTransportPort   |    56 | sourceMacAddress        |
   | 12 | destinationIPv4Address     |    57 |postDestinationMacAddress|
   | 13 | destinationIPv4PrefixLength|    58 | vlanId                  |
   | 14 | egressInterface            |    59 | postVlanId              |
   | 15 | ipNextHopIPv4Address       |    60 | ipVersion               |
   | 16 | bgpSourceAsNumber          |    61 | flowDirection           |
   | 17 | bgpDestinationAsNumber     |    62 | ipNextHopIPv6Address    |
   | 18 | bgpNexthopIPv4Address      |    63 | bgpNexthopIPv6Address   |
   | 19 | postMCastPacketDeltaCount  |    64 | ipv6ExtensionHeaders    |
   | 20 | postMCastOctetDeltaCount   | 65-69 | RESERVED                |
   | 21 | flowEndSysUpTime           |    70 | mplsTopLabelStackSection|
   | 22 | flowStartSysUpTime         |    71 | mplsLabelStackSection2  |
   | 23 | postOctetDeltaCount        |    72 | mplsLabelStackSection3  |
   | 24 | postPacketDeltaCount       |    73 | mplsLabelStackSection4  |
   | 25 | minimumIpTotalLength       |    74 | mplsLabelStackSection5  |
   | 26 | maximumIpTotalLength       |    75 | mplsLabelStackSection6  |
   | 27 | sourceIPv6Address          |    76 | mplsLabelStackSection7  |
   | 28 | destinationIPv6Address     |    77 | mplsLabelStackSection8  |
   | 29 | sourceIPv6PrefixLength     |    78 | mplsLabelStackSection9  |
   | 30 | destinationIPv6PrefixLength|    79 | mplsLabelStackSection10 |
   | 31 | flowLabelIPv6              |    80 | destinationMacAddress   |
   | 32 | icmpTypeCodeIPv4           |    81 | postSourceMacAddress    |
   | 33 | igmpType                   | 82-84 | RESERVED                |
   | 34 | RESERVED                   |    85 | octetTotalCount         |
   | 35 | RESERVED                   |    86 | packetTotalCount        |
   | 36 | flowActiveTimeout          |    87 | RESERVED                |
   | 37 | flowIdleTimeout            |    88 | fragmentOffset          |
   | 38 | RESERVED                   |    89 | RESERVED                |
   | 39 | RESERVED                   |    90 |mplsVpnRouteDistinguisher|
   | 40 | exportedOctetTotalCount    |91-127 | RESERVED                |
   | 41 | exportedMessageTotalCount  |       |                         |
   | 42 |exportedFlowRecordTotalCount|       |                         |
   +----+----------------------------+-------+-------------------------+
   The following list gives an overview of the Information Element
   identifiers that are specified in Section 5 and extends the list of
   Information Element identifiers specified already in [RFC3954].

   +-----+---------------------------+-----+---------------------------+
   |  ID | Name                      |  ID | Name                      |
   +-----+---------------------------+-----+---------------------------+
   | 128 | bgpNextAdjacentAsNumber   | 169 | destinationIPv6Prefix     |
   | 129 | bgpPrevAdjacentAsNumber   | 170 | sourceIPv6Prefix          |
   | 130 | exporterIPv4Address       | 171 | postOctetTotalCount       |
   | 131 | exporterIPv6Address       | 172 | postPacketTotalCount      |
   | 132 | droppedOctetDeltaCount    | 173 | flowKeyIndicator          |
   | 133 | droppedPacketDeltaCount   | 174 | postMCastPacketTotalCount |
   | 134 | droppedOctetTotalCount    | 175 | postMCastOctetTotalCount  |
   | 135 | droppedPacketTotalCount   | 176 | icmpTypeIPv4              |
   | 136 | flowEndReason             | 177 | icmpCodeIPv4              |
   | 137 | commonPropertiesId        | 178 | icmpTypeIPv6              |
   | 138 | observationPointId        | 179 | icmpCodeIPv6              |
   | 139 | icmpTypeCodeIPv6          | 180 | udpSourcePort             |
   | 140 | mplsTopLabelIPv6Address   | 181 | udpDestinationPort        |
   | 141 | lineCardId                | 182 | tcpSourcePort             |
   | 142 | portId                    | 183 | tcpDestinationPort        |
   | 143 | meteringProcessId         | 184 | tcpSequenceNumber         |
   | 144 | exportingProcessId        | 185 | tcpAcknowledgementNumber  |
   | 145 | templateId                | 186 | tcpWindowSize             |
   | 146 | wlanChannelId             | 187 | tcpUrgentPointer          |
   | 147 | wlanSSID                  | 188 | tcpHeaderLength           |
   | 148 | flowId                    | 189 | ipHeaderLength            |
   | 149 | observationDomainId       | 190 | totalLengthIPv4           |
   | 150 | flowStartSeconds          | 191 | payloadLengthIPv6         |
   | 151 | flowEndSeconds            | 192 | ipTTL                     |
   | 152 | flowStartMilliseconds     | 193 | nextHeaderIPv6            |
   | 153 | flowEndMilliseconds       | 194 | mplsPayloadLength         |
   | 154 | flowStartMicroseconds     | 195 | ipDiffServCodePoint       |
   | 155 | flowEndMicroseconds       | 196 | ipPrecedence              |
   | 156 | flowStartNanoseconds      | 197 | fragmentFlags             |
   | 157 | flowEndNanoseconds        | 198 | octetDeltaSumOfSquares    |
   | 158 | flowStartDeltaMicroseconds| 199 | octetTotalSumOfSquares    |
   | 159 | flowEndDeltaMicroseconds  | 200 | mplsTopLabelTTL           |
   | 160 | systemInitTimeMilliseconds| 201 | mplsLabelStackLength      |
   | 161 | flowDurationMilliseconds  | 202 | mplsLabelStackDepth       |
   | 162 | flowDurationMicroseconds  | 203 | mplsTopLabelExp           |
   | 163 | observedFlowTotalCount    | 204 | ipPayloadLength           |
   | 164 | ignoredPacketTotalCount   | 205 | udpMessageLength          |
   | 165 | ignoredOctetTotalCount    | 206 | isMulticast               |
   | 166 | notSentFlowTotalCount     | 207 | ipv4IHL                   |
   | 167 | notSentPacketTotalCount   | 208 | ipv4Options               |
   | 168 | notSentOctetTotalCount    | 209 | tcpOptions                |
   +-----+---------------------------+-----+---------------------------+
   |  ID | Name                      |  ID | Name                      |
   +-----+---------------------------+-----+---------------------------+
   | 210 | paddingOctets             | 218 | tcpSynTotalCount          |
   | 211 | collectorIPv4Address      | 219 | tcpFinTotalCount          |
   | 212 | collectorIPv6Address      | 220 | tcpRstTotalCount          |
   | 213 | collectorInterface        | 221 | tcpPshTotalCount          |
   | 214 | collectorProtocolVersion  | 222 | tcpAckTotalCount          |
   | 215 | collectorTransportProtocol| 223 | tcpUrgTotalCount          |
   | 216 | collectorTransportPort    | 224 | ipTotalLength             |
   | 217 | exporterTransportPort     | 237 | postMplsTopLabelExp       |
   |     |                           | 238 | tcpWindowScale            |
   +-----+---------------------------+-----+---------------------------+

5.  Information Elements

   This section describes the Information Elements of the IPFIX
   information model.  The elements are grouped into 12 groups according
   to their semantics and their applicability:

   1.   Identifiers
   2.   Metering and Exporting Process Configuration
   3.   Metering and Exporting Process Statistics
   4.   IP Header Fields
   5.   Transport Header Fields
   6.   Sub-IP Header Fields
   7.   Derived Packet Properties
   8.   Min/Max Flow Properties
   9.   Flow Timestamps
   10.  Per-Flow Counters
   11.  Miscellaneous Flow Properties
   12.  Padding

   The Information Elements that are derived from fields of packets or
   from packet treatment, such as the Information Elements in groups
   4-7, can serve as Flow Keys used for mapping packets to Flows.

   If they do not serve as Flow Keys, their value may change from packet
   to packet within a single Flow.  For Information Elements with values
   that are derived from fields of packets or from packet treatment and
   for which the value may change from packet to packet within a single
   Flow, the IPFIX information model defines that their value is
   determined by the first packet observed for the corresponding Flow,
   unless the description of the Information Element explicitly
   specifies a different semantics.  This simple rule allows writing all
   Information Elements related to header fields once when the first
   packet of the Flow is observed.  For further observed packets of the
   same Flow, only Flow properties that depend on more than one packet,
   such as the Information Elements in groups 8-11, need to be updated.

   Information Elements with a name having the "post" prefix, for
   example, "postClassOfServiceIPv4", do not report properties that were
   actually observed at the Observation Point, but retrieved by other
   means within the Observation Domain.  These Information Elements can
   be used if there are middlebox functions within the Observation
   Domain changing Flow properties after packets passed the Observation
   Point.

   Information Elements in this section use the reference property to
   reference [RFC0768], [RFC0791], [RFC0792], [RFC0793], [RFC1108],
   [RFC1112], [RFC1191], [RFC1323], [RFC1385], [RFC1812], [RFC1930],
   [RFC2113], [RFC2119], [RFC2460], [RFC2675], [RFC2863], [RFC3031],
   [RFC3032], [RFC3193], [RFC3234], [RFC3260], [RFC3270], [RFC3376],
   [RFC3954], [RFC4271], [RFC4291], [RFC4302], [RFC4303], [RFC4364],
   [RFC4382], [RFC4443],[RFC4960], [RFC4443], [RFC4960], [RFC5036], [IEEE.802-11.1999],
   [IEEE.802-1Q.2003], and [IEEE.802-3.2002].

5.1.  Identifiers

   Information Elements grouped in the table below are identifying
   components of the IPFIX architecture, of an IPFIX Device, or of the
   IPFIX protocol.  All of them have an integral abstract data type and
   data type semantics "identifier" as described in Section 3.2.4.

   Typically, some of them are used for limiting scopes of other
   Information Elements.  However, other Information Elements MAY be
   used for limiting scopes.  Note also that all Information Elements
   listed below MAY be used for other purposes than limiting scopes.

   +-----+---------------------------+-----+---------------------------+
   |  ID | Name                      |  ID | Name                      |
   +-----+---------------------------+-----+---------------------------+
   | 141 | lineCardId                | 148 | flowId                    |
   | 142 | portId                    | 145 | templateId                |
   |  10 | ingressInterface          | 149 | observationDomainId       |
   |  14 | egressInterface           | 138 | observationPointId        |
   | 143 | meteringProcessId         | 137 | commonPropertiesId        |
   | 144 | exportingProcessId        |     |                           |
   +-----+---------------------------+-----+---------------------------+

5.1.1.  lineCardId

   Description:
      An identifier of a line card that is unique per IPFIX Device
      hosting an Observation Point.  Typically, this Information Element
      is used for limiting the scope of other Information Elements.
   Abstract Data Type: unsigned32
   Data Type Semantics: identifier
   ElementId: 141
   Status: current

5.1.2.  portId

   Description:
      An identifier of a line port that is unique per IPFIX Device
      hosting an Observation Point.  Typically, this Information Element
      is used for limiting the scope of other Information Elements.
   Abstract Data Type: unsigned32
   Data Type Semantics: identifier
   ElementId: 142
   Status: current

5.1.3.  ingressInterface

   Description:
      The index of the IP interface where packets of this Flow are being
      received.  The value matches the value of managed object 'ifIndex'
      as defined in RFC 2863.  Note that ifIndex values are not assigned
      statically to an interface and that the interfaces may be
      renumbered every time the device's management system is
      re-initialized, as specified in RFC 2863.
   Abstract Data Type: unsigned32
   Data Type Semantics: identifier
   ElementId: 10
   Status: current
   Reference:
      See RFC 2863 for the definition of the ifIndex object.

5.1.4.  egressInterface

   Description:
      The index of the IP interface where packets of this Flow are being
      sent.  The value matches the value of managed object 'ifIndex' as
      defined in RFC 2863.  Note that ifIndex values are not assigned
      statically to an interface and that the interfaces may be
      renumbered every time the device's management system is
      re-initialized, as specified in RFC 2863.
   Abstract Data Type: unsigned32
   Data Type Semantics: identifier
   ElementId: 14
   Status: current
   Reference:
      See RFC 2863 for the definition of the ifIndex object.

5.1.5.  meteringProcessId

   Description:
      An identifier of a Metering Process that is unique per IPFIX
      Device.  Typically, this Information Element is used for limiting
      the scope of other Information Elements.  Note that process
      identifiers are typically assigned dynamically.  The Metering
      Process may be re-started with a different ID.
   Abstract Data Type: unsigned32
   Data Type Semantics: identifier
   ElementId: 143
   Status: current

5.1.6.  exportingProcessId

   Description:
      An identifier of an Exporting Process that is unique per IPFIX
      Device.  Typically, this Information Element is used for limiting
      the scope of other Information Elements.  Note that process
      identifiers are typically assigned dynamically.  The Exporting
      Process may be re-started with a different ID.
   Abstract Data Type: unsigned32
   Data Type Semantics: identifier
   ElementId: 144
   Status: current

5.1.7.  flowId

   Description:
      An identifier of a Flow that is unique within an Observation
      Domain.  This Information Element can be used to distinguish
      between different Flows if Flow Keys such as IP addresses and port
      numbers are not reported or are reported in separate records.
   Abstract Data Type: unsigned64
   Data Type Semantics: identifier
   ElementId: 148
   Status: current

5.1.8.  templateId

   Description:
      An identifier of a Template that is locally unique within a
      combination of a Transport session and an Observation Domain.
      Template IDs 0-255 are reserved for Template Sets, Options
      Template Sets, and other reserved Sets yet to be created.
      Template IDs of Data Sets are numbered from 256 to 65535.
      Typically, this Information Element is used for limiting the scope
      of other Information Elements.  Note that after a re-start of the
      Exporting Process Template identifiers may be re-assigned.
   Abstract Data Type: unsigned16
   Data Type Semantics: identifier
   ElementId: 145
   Status: current

5.1.9.  observationDomainId

   Description:
      An identifier of an Observation Domain that is locally unique to
      an Exporting Process.  The Exporting Process uses the Observation
      Domain ID to uniquely identify to the Collecting Process the
      Observation Domain where Flows were metered.  It is RECOMMENDED
      that this identifier is also unique per IPFIX Device.  A value of
      0 indicates that no specific Observation Domain is identified by
      this Information Element.  Typically, this Information Element is
      used for limiting the scope of other Information Elements.
   Abstract Data Type: unsigned32
   Data Type Semantics: identifier
   ElementId: 149
   Status: current

5.1.10.  observationPointId

   Description:
      An identifier of an Observation Point that is unique per
      Observation Domain.  It is RECOMMENDED that this identifier is
      also unique per IPFIX Device.  Typically, this Information Element
      is used for limiting the scope of other Information Elements.
   Abstract Data Type: unsigned32
   Data Type Semantics: identifier
   ElementId: 138
   Status: current

5.1.11.  commonPropertiesId

   Description:
      An identifier of a set of common properties that is unique per
      Observation Domain and Transport Session.  Typically, this
      Information Element is used to link to information reported in
      separate Data Records.
   Abstract Data Type: unsigned64
   Data Type Semantics: identifier
   ElementId: 137
   Status: current

5.2.  Metering and Exporting Process Configuration

   Information Elements in this section describe the configuration of
   the Metering Process or the Exporting Process.  The set of these
   Information Elements is listed in the table below.

   +-----+--------------------------+-----+----------------------------+
   |  ID | Name                     |  ID | Name                       |
   +-----+--------------------------+-----+----------------------------+
   | 130 | exporterIPv4Address      | 213 | collectorInterface         |
   | 131 | exporterIPv6Address      | 214 | collectorProtocolVersion   |
   | 217 | exporterTransportPort    | 215 | collectorTransportProtocol |
   | 211 | collectorIPv4Address     | 216 | collectorTransportPort     |
   | 212 | collectorIPv6Address     | 173 | flowKeyIndicator           |
   +-----+--------------------------+-----+----------------------------+

5.2.1.  exporterIPv4Address

Description:
      The IPv4 address used by the Exporting Process.  This is used by
      the Collector to identify the Exporter in cases where the identity
      of the Exporter may have been obscured by the use of a proxy.
   Abstract Data Type: ipv4Address
   Data Type Semantics: identifier
   ElementId: 130
   Status: current

5.2.2.  exporterIPv6Address

   Description:
      The IPv6 address used by the Exporting Process.  This is used by
      the Collector to identify the Exporter in cases where the identity
      of the Exporter may have been obscured by the use of a proxy.
   Abstract Data Type: ipv6Address
   Data Type Semantics: identifier
   ElementId: 131
   Status: current

5.2.3.  exporterTransportPort

   Description:
      The source port identifier from which the Exporting Process sends
      Flow information.  For the transport protocols UDP, TCP, and SCTP,
      this is the source port number.  This field MAY also be used for
      future transport protocols that have 16-bit source port
      identifiers.  This field may be useful for distinguishing multiple
      Exporting Processes that use the same IP address.
   Abstract Data Type: unsigned16
   Data Type Semantics: identifier
   ElementId: 217
   Status: current
   Reference:
      See RFC 768 for the definition of the UDP source port field.  See
      RFC 793 for the definition of the TCP source port field.  See RFC
      4960 for the definition of SCTP.  Additional information on
      defined UDP and TCP port numbers can be found at
      http://www.iana.org/assignments/port-numbers.

5.2.4.  collectorIPv4Address

   Description:
      An IPv4 address to which the Exporting Process sends Flow
      information.
   Abstract Data Type: ipv4Address
   Data Type Semantics: identifier
   ElementId: 211
   Status: current

5.2.5.  collectorIPv6Address

   Description:
      An IPv6 address to which the Exporting Process sends Flow
      information.
   Abstract Data Type: ipv6Address
   Data Type Semantics: identifier
   ElementId: 212
   Status: current

5.2.6.  collectorInterface

   Description:
      The index of the interface from which IPFIX Messages sent by the
      Exporting Process to a Collector leave the IPFIX Device.  The
      value matches the value of managed object 'ifIndex' as defined in
      RFC 2863.  Note that ifIndex values are not assigned statically to
      an interface and that the interfaces may be renumbered every time
      the device's management system is re-initialized, as specified in
      RFC 2863.
   Abstract Data Type: unsigned32
   Data Type Semantics: identifier
   ElementId: 213
   Status: current
   Reference:
      See RFC 2863 for the definition of the ifIndex object.

5.2.7.  collectorProtocolVersion

   Description:
      The protocol version used by the Exporting Process for sending
      Flow information.  The protocol version is given by the value of
      the Version Number field in the Message Header.  The protocol
      version is 10 for IPFIX and 9 for NetFlow version 9.  A value of 0
      indicates that no export protocol is in use.
   Abstract Data Type: unsigned8
   Data Type Semantics: identifier
   ElementId: 214
   Status: current
   Reference:
      See the IPFIX protocol specification [RFC5101] for the definition
      of the IPFIX Message Header.
      See RFC 3954 for the definition of the NetFlow version 9 message
      header.

5.2.8.  collectorTransportProtocol

   Description:
      The value of the protocol number used by the Exporting Process for
      sending Flow information.  The protocol number identifies the IP
      packet payload type.  Protocol numbers are defined in the IANA
      Protocol Numbers registry.
      In Internet Protocol version 4 (IPv4), this is carried in the
      Protocol field.  In Internet Protocol version 6 (IPv6), this is
      carried in the Next Header field in the last extension header of
      the packet.
   Abstract Data Type: unsigned8
   Data Type Semantics: identifier
   ElementId: 215
   Status: current
   Reference:
      See RFC 791 for the specification of the IPv4 protocol field.  See
      RFC 2460 for the specification of the IPv6 protocol field.  See
      the list of protocol numbers assigned by IANA at
      http://www.iana.org/assignments/protocol-numbers.

5.2.9.  collectorTransportPort

   Description:
      The destination port identifier to which the Exporting Process
      sends Flow information.  For the transport protocols UDP, TCP, and
      SCTP, this is the destination port number.  This field MAY also be
      used for future transport protocols that have 16-bit source port
      identifiers.
   Abstract Data Type: unsigned16
   Data Type Semantics: identifier
   ElementId: 216
   Status: current
   Reference:
      See RFC 768 for the definition of the UDP destination port field.
      See RFC 793 for the definition of the TCP destination port field.
      See RFC 4960 for the definition of SCTP.
      Additional information on defined UDP and TCP port numbers can be
      found at http://www.iana.org/assignments/port-numbers.

5.2.10.  flowKeyIndicator

   Description:
      This set of bit fields is used for marking the Information
      Elements of a Data Record that serve as Flow Key.  Each bit
      represents an Information Element in the Data Record with the n-th
      bit representing the n-th Information Element.  A bit set to value
      1 indicates that the corresponding Information Element is a Flow
      Key of the reported Flow.  A bit set to value 0 indicates that
      this is not the case.
      If the Data Record contains more than 64 Information Elements, the
      corresponding Template SHOULD be designed such that all Flow Keys
      are among the first 64 Information Elements, because the
      flowKeyIndicator only contains 64 bits.  If the Data Record
      contains less than 64 Information Elements, then the bits in the
      flowKeyIndicator for which no corresponding Information Element
      exists MUST have the value 0.
   Abstract Data Type: unsigned64
   Data Type Semantics: flags
   ElementId: 173
   Status: current

5.3.  Metering and Exporting Process Statistics

   Information Elements in this section describe statistics of the
   Metering Process and/or the Exporting Process.  The set of these
   Information Elements is listed in the table below.

   +-----+-----------------------------+-----+-------------------------+
   |  ID | Name                        |  ID | Name                    |
   +-----+-----------------------------+-----+-------------------------+
   |  41 | exportedMessageTotalCount   | 165 | ignoredOctetTotalCount  |
   |  40 | exportedOctetTotalCount     | 166 | notSentFlowTotalCount   |
   |  42 | exportedFlowRecordTotalCount| 167 | notSentPacketTotalCount |
   | 163 | observedFlowTotalCount      | 168 | notSentOctetTotalCount  |
   | 164 | ignoredPacketTotalCount     |     |                         |
   +-----+-----------------------------+-----+-------------------------+

5.3.1.  exportedMessageTotalCount

   Description:
      The total number of IPFIX Messages that the Exporting Process sent
      since the Exporting Process (re-)initialization to the Collecting
      Process receiving a report that contains this Information Element.
      The reported number excludes the IPFIX Message that carries the
      counter value.
   Abstract Data Type: unsigned64
   Data Type Semantics: totalCounter
   ElementId: 41
   Status: current
   Units: messages

5.3.2.  exportedOctetTotalCount

   Description:
      The total number of octets that the Exporting Process successfully
      sent since the Exporting Process (re-)initialization to the
      Collecting Process receiving a report that contains this
      Information Element.  The value of this Information Element is
      calculated by summing up the IPFIX Message Header length values of
      all IPFIX Messages that were successfully sent to the Collecting
      Process receiving a report that contains this Information Element.
      The reported number excludes octets in the IPFIX Message that
      carries the counter value.
   Abstract Data Type: unsigned64
   Data Type Semantics: totalCounter
   ElementId: 40
   Status: current
   Units: octets

5.3.3.  exportedFlowRecordTotalCount

   Description:
      The total number of Flow Records that the Exporting Process
      successfully sent as Data Records since the Exporting Process
      (re-)initialization to the Collecting Process receiving a report
      that contains this Information Element.  The reported number
      excludes Flow Records in the IPFIX Message that carries the
      counter value.
   Abstract Data Type: unsigned64
   Data Type Semantics: totalCounter
   ElementId: 42
   Status: current
   Units: flows

5.3.4.  observedFlowTotalCount

   Description:
      The total number of Flows observed in the Observation Domain since
      the Metering Process (re-)initialization for this Observation
      Point.
   Abstract Data Type: unsigned64
   Data Type Semantics: totalCounter
   ElementId: 163
   Status: current
   Units: flows

5.3.5.  ignoredPacketTotalCount

   Description:
      The total number of observed IP packets that the Metering Process
      did not process since the (re-)initialization of the Metering
      Process.
   Abstract Data Type: unsigned64
   Data Type Semantics: totalCounter
   ElementId: 164
   Status: current
   Units: packets

5.3.6.  ignoredOctetTotalCount

   Description:
      The total number of octets in observed IP packets (including the
      IP header) that the Metering Process did not process since the
      (re-)initialization of the Metering Process.
   Abstract Data Type: unsigned64
   Data Type Semantics: totalCounter
   ElementId: 165
   Status: current
   Units: octets

5.3.7.  notSentFlowTotalCount

   Description:
      The total number of Flow Records that were generated by the
      Metering Process and dropped by the Metering Process or by the
      Exporting Process instead of being sent to the Collecting Process.
      There are several potential reasons for this including resource
      shortage and special Flow export policies.
   Abstract Data Type: unsigned64
   Data Type Semantics: totalCounter
   ElementId: 166
   Status: current
   Units: flows

5.3.8.  notSentPacketTotalCount

   Description:
      The total number of packets in Flow Records that were generated by
      the Metering Process and dropped by the Metering Process or by the
      Exporting Process instead of being sent to the Collecting Process.
      There are several potential reasons for this including resource
      shortage and special Flow export policies.
   Abstract Data Type: unsigned64
   Data Type Semantics: totalCounter
   ElementId: 167
   Status: current
   Units: packets

5.3.9.  notSentOctetTotalCount

   Description:
      The total number of octets in packets in Flow Records that were
      generated by the Metering Process and dropped by the Metering
      Process or by the Exporting Process instead of being sent to the
      Collecting Process.  There are several potential reasons for this
      including resource shortage and special Flow export policies.
   Abstract Data Type: unsigned64
   Data Type Semantics: totalCounter
   ElementId: 168
   Status: current
   Units: octets

5.4.  IP Header Fields

   Information Elements in this section indicate values of IP header
   fields or are derived from IP header field values in combination with
   further information.

   +-----+----------------------------+-----+--------------------------+
   |  ID | Name                       |  ID | Name                     |
   +-----+----------------------------+-----+--------------------------+
   |  60 | ipVersion                  | 193 | nextHeaderIPv6           |
   |   8 | sourceIPv4Address          | 195 | ipDiffServCodePoint      |
   |  27 | sourceIPv6Address          | 196 | ipPrecedence             |
   |   9 | sourceIPv4PrefixLength     |   5 | ipClassOfService         |
   |  29 | sourceIPv6PrefixLength     |  55 | postIpClassOfService     |
   |  44 | sourceIPv4Prefix           |  31 | flowLabelIPv6            |
   | 170 | sourceIPv6Prefix           | 206 | isMulticast              |
   |  12 | destinationIPv4Address     |  54 | fragmentIdentification   |
   |  28 | destinationIPv6Address     |  88 | fragmentOffset           |
   |  13 | destinationIPv4PrefixLength| 197 | fragmentFlags            |
   |  30 | destinationIPv6PrefixLength| 189 | ipHeaderLength           |
   |  45 | destinationIPv4Prefix      | 207 | ipv4IHL                  |
   | 169 | destinationIPv6Prefix      | 190 | totalLengthIPv4          |
   | 192 | ipTTL                      | 224 | ipTotalLength            |
   |   4 | protocolIdentifier         | 191 | payloadLengthIPv6        |
   +-----+----------------------------+-----+--------------------------+

5.4.1.  ipVersion

   Description:
      The IP version field in the IP packet header.
   Abstract Data Type: unsigned8
   Data Type Semantics: identifier
   ElementId: 60
   Status: current
   Reference:
      See RFC 791 for the definition of the version field in the IPv4
      packet header.  See RFC 2460 for the definition of the version
      field in the IPv6 packet header.  Additional information on
      defined version numbers can be found at
      http://www.iana.org/assignments/version-numbers.

5.4.2.  sourceIPv4Address

   Description:
      The IPv4 source address in the IP packet header.
   Abstract Data Type: ipv4Address
   Data Type Semantics: identifier
   ElementId: 8
   Status: current
   Reference:
      See RFC 791 for the definition of the IPv4 source address field.

5.4.3.  sourceIPv6Address

   Description:
      The IPv6 source address in the IP packet header.
   Abstract Data Type: ipv6Address
   Data Type Semantics: identifier
   ElementId: 27
   Status: current
   Reference:
      See RFC 2460 for the definition of the Source Address field in the
      IPv6 header.

5.4.4.  sourceIPv4PrefixLength

   Description:
      The number of contiguous bits that are relevant in the
      sourceIPv4Prefix Information Element.
   Abstract Data Type: unsigned8
   ElementId: 9
   Status: current
   Units: bits
   Range: The valid range is 0-32.

5.4.5.  sourceIPv6PrefixLength

   Description:
      The number of contiguous bits that are relevant in the
      sourceIPv6Prefix Information Element.
   Abstract Data Type: unsigned8
   ElementId: 29
   Status: current
   Units: bits
   Range: The valid range is 0-128.

5.4.6.  sourceIPv4Prefix

   Description:
      IPv4 source address prefix.
   Abstract Data Type: ipv4Address
   ElementId: 44
   Status: current

5.4.7.  sourceIPv6Prefix

   Description:
      IPv6 source address prefix.
   Abstract Data Type: ipv6Address
   ElementId: 170
   Status: current

5.4.8.  destinationIPv4Address

   Description:
      The IPv4 destination address in the IP packet header.
   Abstract Data Type: ipv4Address
   Data Type Semantics: identifier
   ElementId: 12
   Status: current
   Reference:
      See RFC 791 for the definition of the IPv4 destination address
      field.

5.4.9.  destinationIPv6Address

   Description:
      The IPv6 destination address in the IP packet header.
   Abstract Data Type: ipv6Address
   Data Type Semantics: identifier
   ElementId: 28
   Status: current
   Reference:
      See RFC 2460 for the definition of the Destination Address field
      in the IPv6 header.

5.4.10.  destinationIPv4PrefixLength

   Description:
      The number of contiguous bits that are relevant in the
      destinationIPv4Prefix Information Element.
   Abstract Data Type: unsigned8
   ElementId: 13
   Status: current
   Units: bits
   Range: The valid range is 0-32.

5.4.11.  destinationIPv6PrefixLength

   Description:
      The number of contiguous bits that are relevant in the
      destinationIPv6Prefix Information Element.
   Abstract Data Type: unsigned8
   ElementId: 30
   Status: current
   Units: bits
   Range: The valid range is 0-128.

5.4.12.  destinationIPv4Prefix

   Description:
      IPv4 destination address prefix.
   Abstract Data Type: ipv4Address
   ElementId: 45
   Status: current

5.4.13.  destinationIPv6Prefix

   Description:
      IPv6 destination address prefix.
   Abstract Data Type: ipv6Address
   ElementId: 169
   Status: current

5.4.14.  ipTTL

   Description:
      For IPv4, the value of the Information Element matches the value
      of the Time to Live (TTL) field in the IPv4 packet header.  For
      IPv6, the value of the Information Element matches the value of
      the Hop Limit field in the IPv6 packet header.
   Abstract Data Type: unsigned8
   ElementId: 192
   Status: current
   Units: hops
   Reference:
      See RFC 791 for the definition of the IPv4 Time to Live field.
      See RFC 2460 for the definition of the IPv6 Hop Limit field.

5.4.15.  protocolIdentifier

   Description:
      The value of the protocol number in the IP packet header.  The
      protocol number identifies the IP packet payload type.  Protocol
      numbers are defined in the IANA Protocol Numbers registry.  In
      Internet Protocol version 4 (IPv4), this is carried in the
      Protocol field.  In Internet Protocol version 6 (IPv6), this is
      carried in the Next Header field in the last extension header of
      the packet.
   Abstract Data Type: unsigned8
   Data Type Semantics: identifier
   ElementId: 4
   Status: current
   Reference:
      See RFC 791 for the specification of the IPv4 protocol field.  See
      RFC 2460 for the specification of the IPv6 protocol field.  See
      the list of protocol numbers assigned by IANA at
      http://www.iana.org/assignments/protocol-numbers.

5.4.16.  nextHeaderIPv6

   Description:
      The value of the Next Header field of the IPv6 header.  The value
      identifies the type of the following IPv6 extension header or of
      the following IP payload.  Valid values are defined in the IANA
      Protocol Numbers registry.
   Abstract Data Type: unsigned8
   ElementId: 193
   Status: current
   Reference:
      See RFC 2460 for the definition of the IPv6 Next Header field.
      See the list of protocol numbers assigned by IANA at
      http://www.iana.org/assignments/protocol-numbers.

5.4.17.  ipDiffServCodePoint

   Description:
      The value of a Differentiated Services Code Point (DSCP) encoded
      in the Differentiated Services field.  The Differentiated Services
      field spans the most significant 6 bits of the IPv4 TOS field or
      the IPv6 Traffic Class field, respectively.
      This Information Element encodes only the 6 bits of the
      Differentiated Services field.  Therefore, its value may range
      from 0 to 63.
   Abstract Data Type: unsigned8
   Data Type Semantics: identifier
   ElementId: 195
   Status: current
   Range: The valid range is 0-63.
   Reference:
      See RFC 3260 for the definition of the Differentiated Services
      field.  See RFC 1812 (Section 5.3.2) and RFC 791 for the
      definition of the IPv4 TOS field.  See RFC 2460 for the definition
      of the IPv6 Traffic Class field.

5.4.18.  ipPrecedence

   Description:
      The value of the IP Precedence.  The IP Precedence value is
      encoded in the first 3 bits of the IPv4 TOS field or the IPv6
      Traffic Class field, respectively.  This Information Element
      encodes only these 3 bits.  Therefore, its value may range from 0
      to 7.
   Abstract Data Type: unsigned8
   Data Type Semantics: identifier
   ElementId: 196
   Status: current
   Range: The valid range is 0-7.
   Reference:
      See RFC 1812 (Section 5.3.3) and RFC 791 for the definition of the
      IP Precedence.  See RFC 1812 (Section 5.3.2) and RFC 791 for the
      definition of the IPv4 TOS field.  See RFC 2460 for the definition
      of the IPv6 Traffic Class field.

5.4.19.  ipClassOfService

   Description:
      For IPv4 packets, this is the value of the TOS field in the IPv4
      packet header.  For IPv6 packets, this is the value of the Traffic
      Class field in the IPv6 packet header.
   Abstract Data Type: unsigned8
   Data Type Semantics: identifier
   ElementId: 5
   Status: current
   Reference:
      See RFC 1812 (Section 5.3.2) and RFC 791 for the definition of the
      IPv4 TOS field.  See RFC 2460 for the definition of the IPv6
      Traffic Class field.

5.4.20.  postIpClassOfService

   Description:
      The definition of this Information Element is identical to the
      definition of Information Element 'ipClassOfService', except that
      it reports a potentially modified value caused by a middlebox
      function after the packet passed the Observation Point.
   Abstract Data Type: unsigned8
   Data Type Semantics: identifier
   ElementId: 55
   Status: current
   Reference:
      See RFC 791 for the definition of the IPv4 TOS field.  See RFC
      2460 for the definition of the IPv6 Traffic Class field.  See RFC
      3234 for the definition of middleboxes.

5.4.21.  flowLabelIPv6

   Description:
      The value of the IPv6 Flow Label field in the IP packet header.
   Abstract Data Type: unsigned32
   Data Type Semantics: identifier
   ElementId: 31
   Status: current
   Reference:
      See RFC 2460 for the definition of the Flow Label field in the
      IPv6 packet header.

5.4.22.  isMulticast

   Description:
      If the IP destination address is not a reserved multicast address,
      then the value of all bits of the octet (including the reserved
      ones) is zero.
      The first bit of this octet is set to 1 if the Version field of
      the IP header has the value 4 and if the Destination Address field
      contains a reserved multicast address in the range from 224.0.0.0
      to 239.255.255.255.  Otherwise, this bit is set to 0.  The second
      and third bits of this octet are reserved for future use.
      The remaining bits of the octet are only set to values other than
      zero if the IP Destination Address is a reserved IPv6 multicast
      address.  Then the fourth bit of the octet is set to the value of
      the T flag in the IPv6 multicast address and the remaining four
      bits are set to the value of the scope field in the IPv6 multicast
      address.

            0      1      2      3      4      5      6      7
         +------+------+------+------+------+------+------+------+
         | MCv4 | RES. | RES. |  T   |   IPv6 multicast scope    |
         +------+------+------+------+------+------+------+------+

         Bit  0:    set to 1 if IPv4 multicast
         Bits 1-2:  reserved for future use
         Bit  4:    set to value of T flag, if IPv6 multicast
         Bits 4-7:  set to value of multicast scope if IPv6 multicast

   Abstract Data Type: unsigned8
   Data Type Semantics: flags
   ElementId: 206
   Status: current
   Reference:
      See RFC 1112 for the specification of reserved IPv4 multicast
      addresses.  See RFC 4291 for the specification of reserved IPv6
      multicast addresses and the definition of the T flag and the IPv6
      multicast scope.

5.4.23.  fragmentIdentification

   Description:
      The value of the Identification field in the IPv4 packet header or
      the IPv6 Fragment header, respectively.  The value is 0 for IPv6
      if there is no fragment header.
   Abstract Data Type: unsigned32
   Data Type Semantics: identifier
   ElementId: 54
   Status: current
   Reference:
      See RFC 791 for the definition of the IPv4 Identification field.
      See RFC 2460 for the definition of the Identification field in the
      IPv6 Fragment header.

5.4.24.  fragmentOffset

   Description:
      The value of the IP fragment offset field in the IPv4 packet
      header or the IPv6 Fragment header, respectively.  The value is 0
      for IPv6 if there is no fragment header.
   Abstract Data Type: unsigned16
   Data Type Semantics: identifier
   ElementId: 88
   Status: current
   Reference:
      See RFC 791 for the specification of the fragment offset in the
      IPv4 header.  See RFC 2460 for the specification of the fragment
      offset in the IPv6 Fragment header.

5.4.25.  fragmentFlags

   Description:
      Fragmentation properties indicated by flags in the IPv4 packet
      header or the IPv6 Fragment header, respectively.

      Bit 0:    (RS) Reserved.
                The value of this bit MUST be 0 until specified
                otherwise.

      Bit 1:    (DF) 0 = May Fragment,  1 = Don't Fragment.
                Corresponds to the value of the DF flag in the
                IPv4 header.  Will always be 0 for IPv6 unless
                a "don't fragment" feature is introduced to IPv6.

      Bit 2:    (MF) 0 = Last Fragment, 1 = More Fragments.
                Corresponds to the MF flag in the IPv4 header
                or to the M flag in the IPv6 Fragment header,
                respectively.  The value is 0 for IPv6 if there
                is no fragment header.

      Bits 3-7: (DC) Don't Care.
                The values of these bits are irrelevant.

           0   1   2   3   4   5   6   7
         +---+---+---+---+---+---+---+---+
         | R | D | M | D | D | D | D | D |
         | S | F | F | C | C | C | C | C |
         +---+---+---+---+---+---+---+---+

   Abstract Data Type: unsigned8
   Data Type Semantics: flags
   ElementId: 197
   Status: current
   Reference:
      See RFC 791 for the specification of the IPv4 fragment flags.  See
      RFC 2460 for the specification of the IPv6 Fragment header.

5.4.26.  ipHeaderLength

   Description:
      The length of the IP header.  For IPv6, the value of this
      Information Element is 40.
   Abstract Data Type: unsigned8
   ElementId: 189
   Status: current
   Units: octets
   Reference:
      See RFC 791 for the specification of the IPv4 header.  See RFC
      2460 for the specification of the IPv6 header.

5.4.27.  ipv4IHL

   Description:
      The value of the Internet Header Length (IHL) field in the IPv4
      header.  It specifies the length of the header in units of 4
      octets.  Please note that its unit is different from most of the
      other Information Elements reporting length values.

   Abstract Data Type: unsigned8
   ElementId: 207
   Status: current
   Units: 4 octets
   Reference:
      See RFC 791 for the specification of the IPv4 header.

5.4.28.  totalLengthIPv4

   Description:
      The total length of the IPv4 packet.
   Abstract Data Type: unsigned16
   ElementId: 190
   Status: current
   Units: octets
   Reference:
      See RFC 791 for the specification of the IPv4 total length.

5.4.29.  ipTotalLength

   Description:
      The total length of the IP packet.
   Abstract Data Type: unsigned64
   ElementId: 224
   Status: current
   Units: octets
   Reference:
      See RFC 791 for the specification of the IPv4 total length.  See
      RFC 2460 for the specification of the IPv6 payload length.  See
      RFC 2675 for the specification of the IPv6 jumbo payload length.

5.4.30.  payloadLengthIPv6

   Description:
      This Information Element reports the value of the Payload Length
      field in the IPv6 header.  Note that IPv6 extension headers belong
      to the payload.  Also note that in case of a jumbo payload option
      the value of the Payload Length field in the IPv6 header is zero
      and so will be the value reported by this Information Element.
   Abstract Data Type: unsigned16
   ElementId: 191
   Status: current
   Reference:
      See RFC 2460 for the specification of the IPv6 payload length.
      See RFC 2675 for the specification of the IPv6 jumbo payload
      option.

5.5.  Transport Header Fields

   The set of Information Elements related to transport header fields
   and length includes the Information Elements listed in the table
   below.

   +-----+---------------------------+-----+---------------------------+
   |  ID | Name                      |  ID | Name                      |
   +-----+---------------------------+-----+---------------------------+
   |   7 | sourceTransportPort       | 238 | tcpWindowScale            |
   |  11 | destinationTransportPort  | 187 | tcpUrgentPointer          |
   | 180 | udpSourcePort             | 188 | tcpHeaderLength           |
   | 181 | udpDestinationPort        |  32 | icmpTypeCodeIPv4          |
   | 205 | udpMessageLength          | 176 | icmpTypeIPv4              |
   | 182 | tcpSourcePort             | 177 | icmpCodeIPv4              |
   | 183 | tcpDestinationPort        | 139 | icmpTypeCodeIPv6          |
   | 184 | tcpSequenceNumber         | 178 | icmpTypeIPv6              |
   | 185 | tcpAcknowledgementNumber  | 179 | icmpCodeIPv6              |
   | 186 | tcpWindowSize             |  33 | igmpType                  |
   +-----+---------------------------+-----+---------------------------+

5.5.1.  sourceTransportPort

   Description:
      The source port identifier in the transport header.  For the
      transport protocols UDP, TCP, and SCTP, this is the source port
      number given in the respective header.  This field MAY also be
      used for future transport protocols that have 16-bit source port
      identifiers.
   Abstract Data Type: unsigned16
   Data Type Semantics: identifier
   ElementId: 7
   Status: current
   Reference:
      See RFC 768 for the definition of the UDP source port field.  See
      RFC 793 for the definition of the TCP source port field.  See RFC
      4960 for the definition of SCTP.
      Additional information on defined UDP and TCP port numbers can be
      found at http://www.iana.org/assignments/port-numbers.

5.5.2.  destinationTransportPort

   Description:
      The destination port identifier in the transport header.  For the
      transport protocols UDP, TCP, and SCTP, this is the destination
      port number given in the respective header.  This field MAY also
      be used for future transport protocols that have 16-bit
      destination port identifiers.

   Abstract Data Type: unsigned16
   Data Type Semantics: identifier
   ElementId: 11
   Status: current
   Reference:
      See RFC 768 for the definition of the UDP destination port field.
      See RFC 793 for the definition of the TCP destination port field.
      See RFC 4960 for the definition of SCTP.  Additional information
      on defined UDP and TCP port numbers can be found at
      http://www.iana.org/assignments/port-numbers.

5.5.3.  udpSourcePort

   Description:
      The source port identifier in the UDP header.
   Abstract Data Type: unsigned16
   Data Type Semantics: identifier
   ElementId: 180
   Status: current
   Reference:
      See RFC 768 for the definition of the UDP source port field.
      Additional information on defined UDP port numbers can be found at
      http://www.iana.org/assignments/port-numbers.

5.5.4.  udpDestinationPort

   Description:
      The destination port identifier in the UDP header.
   Abstract Data Type: unsigned16
   Data Type Semantics: identifier
   ElementId: 181
   Status: current
   Reference:
      See RFC 768 for the definition of the UDP destination port field.
      Additional information on defined UDP port numbers can be found at
      http://www.iana.org/assignments/port-numbers.

5.5.5.  udpMessageLength

   Description:
      The value of the Length field in the UDP header.
   Abstract Data Type: unsigned16
   ElementId: 205
   Status: current
   Units: octets
   Reference:
      See RFC 768 for the specification of the UDP header.

5.5.6.  tcpSourcePort

   Description:
      The source port identifier in the TCP header.
   Abstract Data Type: unsigned16
   Data Type Semantics: identifier
   ElementId: 182
   Status: current
   Reference:
      See RFC 793 for the definition of the TCP source port field.
      Additional information on defined TCP port numbers can be found at
      http://www.iana.org/assignments/port-numbers.

5.5.7.  tcpDestinationPort

   Description:
      The destination port identifier in the TCP header.
   Abstract Data Type: unsigned16
   Data Type Semantics: identifier
   ElementId: 183
   Status: current
   Reference:
      See RFC 793 for the definition of the TCP source port field.
      Additional information on defined TCP port numbers can be found at
      http://www.iana.org/assignments/port-numbers.

5.5.8.  tcpSequenceNumber

   Description:
      The sequence number in the TCP header.
   Abstract Data Type: unsigned32
   ElementId: 184
   Status: current
   Reference:
      See RFC 793 for the definition of the TCP sequence number.

5.5.9.  tcpAcknowledgementNumber

   Description:
      The acknowledgement number in the TCP header.
   Abstract Data Type: unsigned32
   ElementId: 185
   Status: current
   Reference:
      See RFC 793 for the definition of the TCP acknowledgement number.

5.5.10.  tcpWindowSize

   Description:
      The window field in the TCP header.  If the TCP window scale is
      supported, then TCP window scale must be known to fully interpret
      the value of this information.
   Abstract Data Type: unsigned16
   ElementId: 186
   Status: current
   Reference:
      See RFC 793 for the definition of the TCP window field.  See RFC
      1323 for the definition of the TCP window scale.

5.5.11.  tcpWindowScale

   Description:
      The scale of the window field in the TCP header.
   Abstract Data Type: unsigned16
   ElementId: 238
   Status: current
   Reference:
      See RFC 1323 for the definition of the TCP window scale.

5.5.12.  tcpUrgentPointer

   Description:
      The urgent pointer in the TCP header.
   Abstract Data Type: unsigned16
   ElementId: 187
   Status: current
   Reference:
      See RFC 793 for the definition of the TCP urgent pointer.

5.5.13.  tcpHeaderLength

   Description:
      The length of the TCP header.  Note that the value of this
      Information Element is different from the value of the Data Offset
      field in the TCP header.  The Data Offset field indicates the
      length of the TCP header in units of 4 octets.  This Information
      Elements specifies the length of the TCP header in units of
      octets.
   Abstract Data Type: unsigned8
   ElementId: 188
   Status: current
   Units: octets
   Reference:
      See RFC 793 for the definition of the TCP header.

5.5.14.  icmpTypeCodeIPv4

   Description:
      Type and Code of the IPv4 ICMP message.  The combination of both
      values is reported as (ICMP type * 256) + ICMP code.
   Abstract Data Type: unsigned16
   Data Type Semantics: identifier
   ElementId: 32
   Status: current
   Reference:
      See RFC 792 for the definition of the IPv4 ICMP type and code
      fields.

5.5.15.  icmpTypeIPv4

   Description:
      Type of the IPv4 ICMP message.
   Abstract Data Type: unsigned8
   Data Type Semantics: identifier
   ElementId: 176
   Status: current
   Reference:
      See RFC 792 for the definition of the IPv4 ICMP type field.

5.5.16.  icmpCodeIPv4

   Description:
      Code of the IPv4 ICMP message.
   Abstract Data Type: unsigned8
   Data Type Semantics: identifier
   ElementId: 177
   Status: current
   Reference:
      See RFC 792 for the definition of the IPv4 ICMP code field.

5.5.17.  icmpTypeCodeIPv6

   Description:
      Type and Code of the IPv6 ICMP message.  The combination of both
      values is reported as (ICMP type * 256) + ICMP code.
   Abstract Data Type: unsigned16
   Data Type Semantics: identifier
   ElementId: 139
   Status: current
   Reference:
      See RFC 4443 for the definition of the IPv6 ICMP type and code
      fields.

5.5.18.  icmpTypeIPv6

   Description:
      Type of the IPv6 ICMP message.
   Abstract Data Type: unsigned8
   Data Type Semantics: identifier
   ElementId: 178
   Status: current
   Reference:
      See RFC 4443 for the definition of the IPv6 ICMP type field.

5.5.19.  icmpCodeIPv6

   Description:
      Code of the IPv6 ICMP message.
   Abstract Data Type: unsigned8
   Data Type Semantics: identifier
   ElementId: 179
   Status: current
   Reference:
      See RFC 4443 for the definition of the IPv6 ICMP code field.

5.5.20.  igmpType

   Description:
      The type field of the IGMP message.
   Abstract Data Type: unsigned8
   Data Type Semantics: identifier
   ElementId: 33
   Status: current
   Reference:
      See RFC 3376 for the definition of the IGMP type field.

5.6.  Sub-IP Header Fields

   The set of Information Elements related to Sub-IP header fields
   includes the Information Elements listed in the table below.

   +-----+---------------------------+-----+---------------------------+
   |  ID | Name                      |  ID | Name                      |
   +-----+---------------------------+-----+---------------------------+
   |  56 | sourceMacAddress          | 201 | mplsLabelStackLength      |
   |  81 | postSourceMacAddress      | 194 | mplsPayloadLength         |
   |  58 | vlanId                    |  70 | mplsTopLabelStackSection  |
   |  59 | postVlanId                |  71 | mplsLabelStackSection2    |
   |  80 | destinationMacAddress     |  72 | mplsLabelStackSection3    |
   |  57 | postDestinationMacAddress |  73 | mplsLabelStackSection4    |
   | 146 | wlanChannelId             |  74 | mplsLabelStackSection5    |
   | 147 | wlanSSID                  |  75 | mplsLabelStackSection6    |
   | 200 | mplsTopLabelTTL           |  76 | mplsLabelStackSection7    |
   | 203 | mplsTopLabelExp           |  77 | mplsLabelStackSection8    |
   | 237 | postMplsTopLabelExp       |  78 | mplsLabelStackSection9    |
   | 202 | mplsLabelStackDepth       |  79 | mplsLabelStackSection10   |
   +-----+---------------------------+-----+---------------------------+

5.6.1.  sourceMacAddress

   Description:
      The IEEE 802 source MAC address field.
   Abstract Data Type: macAddress
   Data Type Semantics: identifier
   ElementId: 56
   Status: current
   Reference:
      See IEEE.802-3.2002.

5.6.2.  postSourceMacAddress

   Description:
      The definition of this Information Element is identical to the
      definition of Information Element 'sourceMacAddress', except that
      it reports a potentially modified value caused by a middlebox
      function after the packet passed the Observation Point.
   Abstract Data Type: macAddress
   Data Type Semantics: identifier
   ElementId: 81
   Status: current
   Reference:
      See IEEE.802-3.2002.

5.6.3.  vlanId

   Description:
      The IEEE 802.1Q VLAN identifier (VID) extracted from the Tag
      Control Information field that was attached to the IP packet.
   Abstract Data Type: unsigned16
   Data Type Semantics: identifier
   ElementId: 58
   Status: current
   Reference:
      See IEEE.802-1Q.2003.

5.6.4.  postVlanId

   Description:
      The definition of this Information Element is identical to the
      definition of Information Element 'vlanId', except that it reports
      a potentially modified value caused by a middlebox function after
      the packet passed the Observation Point.
   Abstract Data Type: unsigned16
   Data Type Semantics: identifier
   ElementId: 59
   Status: current
   Reference:
      See IEEE.802-1Q.2003.

5.6.5.  destinationMacAddress

   Description:
      The IEEE 802 destination MAC address field.
   Abstract Data Type: macAddress
   Data Type Semantics: identifier
   ElementId: 80
   Status: current
   Reference:
      See IEEE.802-3.2002.

5.6.6.  postDestinationMacAddress

   Description:
      The definition of this Information Element is identical to the
      definition of Information Element 'destinationMacAddress', except
      that it reports a potentially modified value caused by a middlebox
      function after the packet passed the Observation Point.
   Abstract Data Type: macAddress
   Data Type Semantics: identifier
   ElementId: 57
   Status: current
   Reference:
      See IEEE.802-3.2002.

5.6.7.  wlanChannelId

   Description:
      The identifier of the 802.11 (Wi-Fi) channel used.
   Abstract Data Type: unsigned8
   Data Type Semantics: identifier
   ElementId: 146
   Status: current
   Reference:
      See IEEE.802-11.1999.

5.6.8.  wlanSSID

   Description:
      The Service Set IDentifier (SSID) identifying an 802.11 (Wi-Fi)
      network used.  According to IEEE.802-11.1999, the SSID is encoded
      into a string of up to 32 characters.
   Abstract Data Type: string
   ElementId: 147
   Status: current
   Reference:
      See IEEE.802-11.1999.

5.6.9.  mplsTopLabelTTL

   Description:
      The TTL field from the top MPLS label stack entry, i.e., the last
      label that was pushed.
   Abstract Data Type: unsigned8
   ElementId: 200
   Status: current
   Reference:
      See RFC 3032 for the specification of the TTL field.

5.6.10.  mplsTopLabelExp

   Description:
      The Exp field from the top MPLS label stack entry, i.e., the last
      label that was pushed.

      Bits 0-4:  Don't Care, value is irrelevant.
      Bits 5-7:  MPLS Exp field.

          0   1   2   3   4   5   6   7
        +---+---+---+---+---+---+---+---+
        |     don't care    |    Exp    |
        +---+---+---+---+---+---+---+---+

   Abstract Data Type: unsigned8
   Data Type Semantics: flags
   ElementId: 203
   Status: current
   Reference:
      See RFC 3032 for the specification of the Exp field.  See RFC 3270
      for usage of the Exp field.

5.6.11.  postMplsTopLabelExp

   Description:
      The definition of this Information Element is identical to the
      definition of Information Element 'mplsTopLabelExp', except that
      it reports a potentially modified value caused by a middlebox
      function after the packet passed the Observation Point.
   Abstract Data Type: unsigned8
   Data Type Semantics: flags
   ElementId: 237
   Status: current
   Reference:
      See RFC 3032 for the specification of the Exp field.  See RFC 3270
      for usage of the Exp field.

5.6.12.  mplsLabelStackDepth

   Description:
      The number of labels in the MPLS label stack.
   Abstract Data Type: unsigned32
   ElementId: 202
   Status: current
   Units: label stack entries
   Reference:
      See RFC 3032 for the specification of the MPLS label stack.

5.6.13.  mplsLabelStackLength

   Description:
      The length of the MPLS label stack in units of octets.
   Abstract Data Type: unsigned32
   ElementId: 201
   Status: current
   Units: octets
   Reference:
      See RFC 3032 for the specification of the MPLS label stack.

5.6.14.  mplsPayloadLength

   Description:
      The size of the MPLS packet without the label stack.
   Abstract Data Type: unsigned32
   ElementId: 194
   Status: current
   Units: octets
   Reference:
      See RFC 3031 for the specification of MPLS packets.  See RFC 3032
      for the specification of the MPLS label stack.

5.6.15.  mplsTopLabelStackSection

   Description:
      The Label, Exp, and S fields from the top MPLS label stack entry,
      i.e., from the last label that was pushed.  The size of this
      Information Element is 3 octets.

       0                   1                   2
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                Label                  | Exp |S|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      Label:  Label Value, 20 bits
      Exp:    Experimental Use, 3 bits
      S:      Bottom of Stack, 1 bit

   Abstract Data Type: octetArray
   Data Type Semantics: identifier
   ElementId: 70
   Status: current
   Reference:
      See RFC 3032.

5.6.16.  mplsLabelStackSection2

   Description:
      The Label, Exp, and S fields from the label stack entry that was
      pushed immediately before the label stack entry that would be
      reported by mplsTopLabelStackSection.  See the definition of
      mplsTopLabelStackSection for further details.  The size of this
      Information Element is 3 octets.
   Abstract Data Type: octetArray
   Data Type Semantics: identifier
   ElementId: 71
   Status: current
   Reference:
      See RFC 3032.

5.6.17.  mplsLabelStackSection3

   Description:
      The Label, Exp, and S fields from the label stack entry that was
      pushed immediately before the label stack entry that would be
      reported by mplsLabelStackSection2.  See the definition of
      mplsTopLabelStackSection for further details.  The size of this
      Information Element is 3 octets.
   Abstract Data Type: octetArray
   Data Type Semantics: identifier
   ElementId: 72
   Status: current
   Reference:
      See RFC 3032.

5.6.18.  mplsLabelStackSection4

   Description:
      The Label, Exp, and S fields from the label stack entry that was
      pushed immediately before the label stack entry that would be
      reported by mplsLabelStackSection3.  See the definition of
      mplsTopLabelStackSection for further details.  The size of this
      Information Element is 3 octets.
   Abstract Data Type: octetArray
   Data Type Semantics: identifier
   ElementId: 73
   Status: current
   Reference:
      See RFC 3032.

5.6.19.  mplsLabelStackSection5

   Description:
      The Label, Exp, and S fields from the label stack entry that was
      pushed immediately before the label stack entry that would be
      reported by mplsLabelStackSection4.  See the definition of
      mplsTopLabelStackSection for further details.  The size of this
      Information Element is 3 octets.
   Abstract Data Type: octetArray
   Data Type Semantics: identifier
   ElementId: 74
   Status: current
   Reference:
      See RFC 3032.

5.6.20.  mplsLabelStackSection6

   Description:
      The Label, Exp, and S fields from the label stack entry that was
      pushed immediately before the label stack entry that would be
      reported by mplsLabelStackSection5.  See the definition of
      mplsTopLabelStackSection for further details.  The size of this
      Information Element is 3 octets.
   Abstract Data Type: octetArray
   Data Type Semantics: identifier
   ElementId: 75
   Status: current
   Reference:
      See RFC 3032.

5.6.21.  mplsLabelStackSection7

   Description:
      The Label, Exp, and S fields from the label stack entry that was
      pushed immediately before the label stack entry that would be
      reported by mplsLabelStackSection6.  See the definition of
      mplsTopLabelStackSection for further details.  The size of this
      Information Element is 3 octets.
   Abstract Data Type: octetArray
   Data Type Semantics: identifier
   ElementId: 76
   Status: current
   Reference:
      See RFC 3032.

5.6.22.  mplsLabelStackSection8

   Description:
      The Label, Exp, and S fields from the label stack entry that was
      pushed immediately before the label stack entry that would be
      reported by mplsLabelStackSection7.  See the definition of
      mplsTopLabelStackSection for further details.  The size of this
      Information Element is 3 octets.
   Abstract Data Type: octetArray
   Data Type Semantics: identifier
   ElementId: 77
   Status: current
   Reference:
      See RFC 3032.

5.6.23.  mplsLabelStackSection9

   Description:
      The Label, Exp, and S fields from the label stack entry that was
      pushed immediately before the label stack entry that would be
      reported by mplsLabelStackSection8.  See the definition of
      mplsTopLabelStackSection for further details.  The size of this
      Information Element is 3 octets.
   Abstract Data Type: octetArray
   Data Type Semantics: identifier
   ElementId: 78
   Status: current
   Reference:
      See RFC 3032.

5.6.24.  mplsLabelStackSection10

   Description:
      The Label, Exp, and S fields from the label stack entry that was
      pushed immediately before the label stack entry that would be
      reported by mplsLabelStackSection9.  See the definition of
      mplsTopLabelStackSection for further details.  The size of this
      Information Element is 3 octets.
   Abstract Data Type: octetArray
   Data Type Semantics: identifier
   ElementId: 79
   Status: current
   Reference:
      See RFC 3032.

5.7.  Derived Packet Properties

   The set of Information Elements derived from packet properties (for
   example, values of header fields) includes the Information Elements
   listed in the table below.

   +-----+---------------------------+-----+---------------------------+
   |  ID | Name                      |  ID | Name                      |
   +-----+---------------------------+-----+---------------------------+
   | 204 | ipPayloadLength           |  18 | bgpNextHopIPv4Address     |
   |  15 | ipNextHopIPv4Address      |  63 | bgpNextHopIPv6Address     |
   |  62 | ipNextHopIPv6Address      |  46 | mplsTopLabelType          |
   |  16 | bgpSourceAsNumber         |  47 | mplsTopLabelIPv4Address   |
   |  17 | bgpDestinationAsNumber    | 140 | mplsTopLabelIPv6Address   |
   | 128 | bgpNextAdjacentAsNumber   |  90 | mplsVpnRouteDistinguisher |
   | 129 | bgpPrevAdjacentAsNumber   |     |                           |
   +-----+---------------------------+-----+---------------------------+

5.7.1.  ipPayloadLength

   Description:
      The effective length of the IP payload.  For IPv4 packets, the
      value of this Information Element is the difference between the
      total length of the IPv4 packet (as reported by Information
      Element totalLengthIPv4) and the length of the IPv4 header (as
      reported by Information Element headerLengthIPv4).  For IPv6, the
      value of the Payload Length field in the IPv6 header is reported
      except in the case that the value of this field is zero and that
      there is a valid jumbo payload option.  In this case, the value of
      the Jumbo Payload Length field in the jumbo payload option is
      reported.
   Abstract Data Type: unsigned32
   ElementId: 204
   Status: current
   Reference:
      See RFC 791 for the specification of IPv4 packets.  See RFC 2460
      for the specification of the IPv6 payload length.  See RFC 2675
      for the specification of the IPv6 jumbo payload length.

5.7.2.  ipNextHopIPv4Address

   Description:
      The IPv4 address of the next IPv4 hop.
   Abstract Data Type: ipv4Address
   Data Type Semantics: identifier
   ElementId: 15
   Status: current

5.7.3.  ipNextHopIPv6Address

   Description:
      The IPv6 address of the next IPv6 hop.
   Abstract Data Type: ipv6Address
   Data Type Semantics: identifier
   ElementId: 62
   Status: current

5.7.4.  bgpSourceAsNumber

   Description:
      The autonomous system (AS) number of the source IP address.  If AS
      path information for this Flow is only available as an unordered
      AS set (and not as an ordered AS sequence), then the value of this
      Information Element is 0.
   Abstract Data Type: unsigned32
   Data Type Semantics: identifier
   ElementId: 16
   Status: current
   Reference:
      See RFC 4271 for a description of BGP-4, and see RFC 1930 for the
      definition of the AS number.

5.7.5.  bgpDestinationAsNumber

   Description:
      The autonomous system (AS) number of the destination IP address.
      If AS path information for this Flow is only available as an
      unordered AS set (and not as an ordered AS sequence), then the
      value of this Information Element is 0.
   Abstract Data Type: unsigned32
   Data Type Semantics: identifier
   ElementId: 17
   Status: current
   Reference:
      See RFC 4271 for a description of BGP-4, and see RFC 1930 for the
      definition of the AS number.

5.7.6.  bgpNextAdjacentAsNumber

   Description:
      The autonomous system (AS) number of the first AS in the AS path
      to the destination IP address.  The path is deduced by looking up
      the destination IP address of the Flow in the BGP routing
      information base.  If AS path information for this Flow is only
      available as an unordered AS set (and not as an ordered AS
      sequence), then the value of this Information Element is 0.

   Abstract Data Type: unsigned32
   Data Type Semantics: identifier
   ElementId: 128
   Status: current
   Reference:
      See RFC 4271 for a description of BGP-4, and see RFC 1930 for the
      definition of the AS number.

5.7.7.  bgpPrevAdjacentAsNumber

   Description:
      The autonomous system (AS) number of the last AS in the AS path
      from the source IP address.  The path is deduced by looking up the
      source IP address of the Flow in the BGP routing information base.
      If AS path information for this Flow is only available as an
      unordered AS set (and not as an ordered AS sequence), then the
      value of this Information Element is 0.  In case of BGP asymmetry,
      the bgpPrevAdjacentAsNumber might not be able to report the
      correct value.
   Abstract Data Type: unsigned32
   Data Type Semantics: identifier
   ElementId: 129
   Status: current
   Reference:
      See RFC 4271 for a description of BGP-4, and see RFC 1930 for the
      definition of the AS number.

5.7.8.  bgpNextHopIPv4Address

   Description:
      The IPv4 address of the next (adjacent) BGP hop.
   Abstract Data Type: ipv4Address
   Data Type Semantics: identifier
   ElementId: 18
   Status: current
   Reference:
      See RFC 4271 for a description of BGP-4.

5.7.9.  bgpNextHopIPv6Address

   Description:
      The IPv6 address of the next (adjacent) BGP hop.
   Abstract Data Type: ipv6Address
   Data Type Semantics: identifier
   ElementId: 63
   Status: current
   Reference:
      See RFC 4271 for a description of BGP-4.

5.7.10.  mplsTopLabelType

   Description:
      This field identifies the control protocol that
      allocated the top-of-stack label.  Initial values for this field
      are listed below.  Further values may be assigned by IANA in the
      MPLS label type registry.

         -  0x01 TE-MIDPT: Any TE tunnel mid-point or tail label
         -  0x02 Pseudowire: Any PWE3 or Cisco AToM based label
         -  0x03 VPN: Any label associated with VPN
         -  0x04 BGP: Any label associated with BGP or BGP routing
         -  0x05 LDP: Any label associated with dynamically assigned
            labels using LDP

   Abstract Data Type: unsigned8
   Data Type Semantics: identifier
   ElementId: 46
   Status: current
   Reference:
      See RFC 3031 for the MPLS label structure.  See RFC 4364 for the
      association of MPLS labels with Virtual Private Networks (VPNs).
      See RFC 4271 for BGP and BGP routing.  See RFC 5036 for Label
      Distribution Protocol (LDP).  See the list of MPLS label types
      assigned by IANA at
      http://www.iana.org/assignments/mpls-label-values.

5.7.11.  mplsTopLabelIPv4Address

   Description:
      The IPv4 address of the system that the MPLS top label will cause
      this Flow to be forwarded to.
   Abstract Data Type: ipv4Address
   Data Type Semantics: identifier
   ElementId: 47
   Status: current
   Reference:
      See RFC 3031 for the association between MPLS labels and IP
      addresses.

5.7.12.  mplsTopLabelIPv6Address

   Description:
      The IPv6 address of the system that the MPLS top label will cause
      this Flow to be forwarded to.
   Abstract Data Type: ipv6Address
   Data Type Semantics: identifier
   ElementId: 140
   Status: current
   Reference:
      See RFC 3031 for the association between MPLS labels and IP
      addresses.

5.7.13.  mplsVpnRouteDistinguisher

   Description:
      The value of the VPN route distinguisher of a corresponding entry
      in a VPN routing and forwarding table.  Route distinguisher
      ensures that the same address can be used in several different
      MPLS VPNs and that it is possible for BGP to carry several
      completely different routes to that address, one for each VPN.
      According to RFC 4364, the size of mplsVpnRouteDistinguisher is 8
      octets.  However, in RFC 4382 an octet string with flexible length
      was chosen for representing a VPN route distinguisher by object
      MplsL3VpnRouteDistinguisher.  This choice was made in order to be
      open to future changes of the size.  This idea was adopted when
      choosing octetArray as abstract data type for this Information
      Element.  The maximum length of this Information Element is 256
      octets.
   Abstract Data Type: octetArray
   Data Type Semantics: identifier
   ElementId: 90
   Status: current
   Reference:
      See RFC 4364 for the specification of the route distinguisher.
      See RFC 4382 for the specification of the MPLS/BGP Layer 3 Virtual
      Private Network (VPN) Management Information Base.

5.8.  Min/Max Flow Properties

   Information Elements in this section are results of minimum or
   maximum operations over all packets of a Flow.

   +-----+---------------------------+-----+---------------------------+
   |  ID | Name                      |  ID | Name                      |
   +-----+---------------------------+-----+---------------------------+
   |  25 | minimumIpTotalLength      | 208 | ipv4Options               |
   |  26 | maximumIpTotalLength      |  64 | ipv6ExtensionHeaders      |
   |  52 | minimumTTL                |   6 | tcpControlBits            |
   |  53 | maximumTTL                | 209 | tcpOptions                |
   +-----+---------------------------+-----+---------------------------+

5.8.1.  minimumIpTotalLength

   Description:
      Length of the smallest packet observed for this Flow.  The packet
      length includes the IP header(s) length and the IP payload length.
   Abstract Data Type: unsigned64
   ElementId: 25
   Status: current
   Units: octets
   Reference:
      See RFC 791 for the specification of the IPv4 total length.  See
      RFC 2460 for the specification of the IPv6 payload length.  See
      RFC 2675 for the specification of the IPv6 jumbo payload length.

5.8.2.  maximumIpTotalLength

   Description:
      Length of the largest packet observed for this Flow.  The packet
      length includes the IP header(s) length and the IP payload length.
   Abstract Data Type: unsigned64
   ElementId: 26
   Status: current
   Units: octets
   Reference:
      See RFC 791 for the specification of the IPv4 total length.  See
      RFC 2460 for the specification of the IPv6 payload length.  See
      RFC 2675 for the specification of the IPv6 jumbo payload length.

5.8.3.  minimumTTL

   Description:
      Minimum TTL value observed for any packet in this Flow.

   Abstract Data Type: unsigned8
   ElementId: 52
   Status: current

5.8.4.  maximumTTL

   Description:
      Maximum TTL value observed for any packet in this Flow.
   Abstract Data Type: unsigned8
   ElementId: 53
   Status: current

5.8.5.  ipv4Options

   Description:
      IPv4 options in packets of this Flow.  The information is encoded
      in a set of bit fields.  For each valid IPv4 option type, there is
      a bit in this set.  The bit is set to 1 if any observed packet of
      this Flow contains the corresponding IPv4 option type.  Otherwise,
      if no observed packet of this Flow contained the respective IPv4
      option type, the value of the corresponding bit is 0.  The list of
      valid IPv4 options is maintained by IANA.  Note that for
      identifying an option not just the 5-bit Option Number, but all 8
      bits of the Option Type need to match one of the IPv4 options
      specified at http://www.iana.org/assignments/ip-parameters.
      Options are mapped to bits according to their option numbers.
      Option number X is mapped to bit X.  The mapping is illustrated by
      the figure below.

           0      1      2      3      4      5      6      7
       +------+------+------+------+------+------+------+------+
       | EOOL | NOP  | SEC  | LSR  |  TS  |E-SEC |CIPSO |  RR  | ...
       +------+------+------+------+------+------+------+------+

           8      9     10     11     12     13     14     15
       +------+------+------+------+------+------+------+------+
   ... | SID  | SSR  | ZSU  | MTUP | MTUR | FINN | VISA |ENCODE| ...
       +------+------+------+------+------+------+------+------+

          16     17     18     19     20     21     22     23
       +------+------+------+------+------+------+------+------+
   ... |IMITD | EIP  |  TR  |ADDEXT|RTRALT| SDB  |NSAPA | DPS  | ...
       +------+------+------+------+------+------+------+------+

          24     25     26     27     28     29     30     31
       +------+------+------+------+------+------+------+------+
   ... | UMP  |             to be assigned by IANA             |
       +------+------+------+------+------+------+------+------+
          Type   Option
      Bit Value  Name    Reference
      ---+-----+-------+------------------------------------
       0     0   EOOL    End of Options List, RFC 791
       1     1   NOP     No Operation, RFC 791
       2   130   SEC     Security, RFC 1108
       3   131   LSR     Loose Source Route, RFC 791
       4    68   TS      Timestamp,      Time Stamp, RFC 791
       5   133   E-SEC   Extended Security, RFC 1108
       6   134   CIPSO   Commercial Security
       7     7   RR      Record Route, RFC 791
       8   136   SID     Stream ID, RFC 791
       9   137   SSR     Strict Source Route, RFC 791
      10    10   ZSU     Experimental Measurement
      11    11   MTUP    (obsoleted) MTU Probe, RFC 1191
      12    12   MTUR    (obsoleted) MTU Reply, RFC 1191
      13   205   FINN    Experimental Flow Control
      14   142   VISA    Experimental Access Control
      15    15   ENCODE
      16   144   IMITD   IMI Traffic Descriptor
      17   145   EIP     Extended Internet Protocol, RFC 1385
      18    82   TR      Traceroute, RFC 3193
      19   147   ADDEXT  Address Extension
      20   148   RTRALT  Router Alert, RFC 2113
      21   149   SDB     Selective Directed Broadcast
      22   150   NSAPA   NSAP Address
      23   151   DPS     Dynamic Packet State
      24   152   UMP     Upstream Multicast Pkt.
      ...  ...   ...     Further options numbers
                         may be assigned by IANA

   Abstract Data Type: unsigned32
   Data Type Semantics: flags
   ElementId: 208
   Status: current
   Reference:
      See RFC 791 for the definition of IPv4 options.  See the list of
      IPv4 option numbers assigned by IANA at
      http://www.iana.org/assignments/ip-parameters.

5.8.6.  ipv6ExtensionHeaders

   Description:
      IPv6 extension headers observed in packets of this Flow.  The
      information is encoded in a set of bit fields.  For each IPv6
      option header, there is a bit in this set.  The bit is set to 1 if
      any observed packet of this Flow contains the corresponding IPv6
      extension header.  Otherwise, if no observed packet of this Flow
      contained the respective IPv6 extension header, the value of the
      corresponding bit is 0.

              0     1     2     3     4     5     6     7
          +-----+-----+-----+-----+-----+-----+-----+-----+
          | Res | FRA1| RH  | FRA0| UNK | Res | HOP | DST |  ...
          +-----+-----+-----+-----+-----+-----+-----+-----+

              8     9    10    11    12    13    14    15
          +-----+-----+-----+-----+-----+-----+-----+-----+
      ... | PAY | AH  | ESP |         Reserved            | ...
          +-----+-----+-----+-----+-----+-----+-----+-----+

             16    17    18    19    20    21    22    23
          +-----+-----+-----+-----+-----+-----+-----+-----+
      ... |                  Reserved                     | ...
          +-----+-----+-----+-----+-----+-----+-----+-----+

             24    25    26    27    28    29    30    31
          +-----+-----+-----+-----+-----+-----+-----+-----+
      ... |                  Reserved                     |
          +-----+-----+-----+-----+-----+-----+-----+-----+

        Bit    IPv6 Option   Description

       0, Res               Reserved
       1, FRA1     44       Fragmentation header - not first fragment
       2, RH       43       Routing header
       3, FRA0     44       Fragment header - first fragment
       4, UNK               Unknown Layer 4 header
                            (compressed, encrypted, not supported)
       5, Res               Reserved
       6, HOP       0       Hop-by-hop option header
       7, DST      60       Destination option header
       8, PAY     108       Payload compression header
       9, AH       51       Authentication Header
      10, ESP      50       Encrypted security payload
      11 to 31              Reserved
   Abstract Data Type: unsigned32
   Data Type Semantics: flags
   ElementId: 64
   Status: current
   Reference:
      See RFC 2460 for the general definition of IPv6 extension headers
      and for the specification of the hop-by-hop options header, the
      routing header, the fragment header, and the destination options
      header.  See RFC 4302 for the specification of the authentication
      header.  See RFC 4303 for the specification of the encapsulating
      security payload.

5.8.7.  tcpControlBits

   Description:
      TCP control bits observed for packets of this Flow.  The
      information is encoded in a set of bit fields.  For each TCP
      control bit, there is a bit in this set.  A bit is set to 1 if any
      observed packet of this Flow has the corresponding TCP control bit
      set to 1.  A value of 0 for a bit indicates that the corresponding
      bit was not set in any of the observed packets of this Flow.

          0     1     2     3     4     5     6     7
      +-----+-----+-----+-----+-----+-----+-----+-----+
      |  Reserved | URG | ACK | PSH | RST | SYN | FIN |
      +-----+-----+-----+-----+-----+-----+-----+-----+

      Reserved:  Reserved for future use by TCP.  Must be zero.
           URG:  Urgent Pointer field significant
           ACK:  Acknowledgment field significant
           PSH:  Push Function
           RST:  Reset the connection
           SYN:  Synchronize sequence numbers
           FIN:  No more data from sender

   Abstract Data Type: unsigned8
   Data Type Semantics: flags
   ElementId: 6
   Status: current
   Reference:
      See RFC 793 for the definition of the TCP control bits in the TCP
      header.

5.8.8.  tcpOptions

   Description:
      TCP options in packets of this Flow.  The information is encoded
      in a set of bit fields.  For each TCP option, there is a bit in
      this set.  The bit is set to 1 if any observed packet of this Flow
      contains the corresponding TCP option.  Otherwise, if no observed
      packet of this Flow contained the respective TCP option, the value
      of the corresponding bit is 0.
      Options are mapped to bits according to their option numbers.
      Option number X is mapped to bit X. TCP option numbers are
      maintained by IANA.

              0     1     2     3     4     5     6     7
          +-----+-----+-----+-----+-----+-----+-----+-----+
          |   0 |   1 |   2 |   3 |   4 |   5 |   6 |   7 |  ...
          +-----+-----+-----+-----+-----+-----+-----+-----+

              8     9    10    11    12    13    14    15
          +-----+-----+-----+-----+-----+-----+-----+-----+
      ... |   8 |   9 |  10 |  11 |  12 |  13 |  14 |  15 |...
          +-----+-----+-----+-----+-----+-----+-----+-----+

             16    17    18    19    20    21    22    23
          +-----+-----+-----+-----+-----+-----+-----+-----+
      ... |  16 |  17 |  18 |  19 |  20 |  21 |  22 |  23 |...
          +-----+-----+-----+-----+-----+-----+-----+-----+

                                . . .

             56    57    58    59    60    61    62    63
          +-----+-----+-----+-----+-----+-----+-----+-----+
      ... |  56 |  57 |  58 |  59 |  60 |  61 |  62 |  63 |
          +-----+-----+-----+-----+-----+-----+-----+-----+

   Abstract Data Type: unsigned64
   Data Type Semantics: flags
   ElementId: 209
   Status: current
   Reference:
      See RFC 793 for the definition of TCP options.  See the list of
      TCP option numbers assigned by IANA at
      http://www.iana.org/assignments/tcp-parameters.

5.9.  Flow Timestamps

   Information Elements in this section are timestamps of events.

   Timestamps flowStartSeconds, flowEndSeconds, flowStartMilliseconds,
   flowEndMilliseconds, flowStartMicroseconds, flowEndMicroseconds,
   flowStartNanoseconds, flowEndNanoseconds, and
   systemInitTimeMilliseconds are absolute and have a well-defined fixed
   time base, such as, for example, the number of seconds since 0000 UTC
   Jan 1st 1970.

   Timestamps flowStartDeltaMicroseconds and flowEndDeltaMicroseconds
   are relative timestamps only valid within the scope of a single IPFIX
   Message.  They contain the negative time offsets relative to the
   export time specified in the IPFIX Message Header.  The maximum time
   offset that can be encoded by these delta counters is 1 hour, 11
   minutes, and 34.967295 seconds.

   Timestamps flowStartSysUpTime and flowEndSysUpTime are relative
   timestamps indicating the time relative to the last (re-
   )initialization of the IPFIX Device.  For reporting the time of the
   last (re-)initialization, systemInitTimeMilliseconds can be reported,
   for example, in Data Records defined by Option Templates.

   +-----+---------------------------+-----+---------------------------+
   |  ID | Name                      |  ID | Name                      |
   +-----+---------------------------+-----+---------------------------+
   | 150 | flowStartSeconds          | 156 | flowStartNanoseconds      |
   | 151 | flowEndSeconds            | 157 | flowEndNanoseconds        |
   | 152 | flowStartMilliseconds     | 158 | flowStartDeltaMicroseconds|
   | 153 | flowEndMilliseconds       | 159 | flowEndDeltaMicroseconds  |
   | 154 | flowStartMicroseconds     | 160 | systemInitTimeMilliseconds|
   | 155 | flowEndMicroseconds       |  22 | flowStartSysUpTime        |
   |     |                           |  21 | flowEndSysUpTime          |
   +-----+---------------------------+-----+---------------------------+

5.9.1.  flowStartSeconds

   Description:
      The absolute timestamp of the first packet of this Flow.
   Abstract Data Type: dateTimeSeconds
   ElementId: 150
   Status: current
   Units: seconds

5.9.2.  flowEndSeconds

   Description:
      The absolute timestamp of the last packet of this Flow.
   Abstract Data Type: dateTimeSeconds
   ElementId: 151
   Status: current
   Units: seconds

5.9.3.  flowStartMilliseconds

   Description:
      The absolute timestamp of the first packet of this Flow.
   Abstract Data Type: dateTimeMilliseconds
   ElementId: 152
   Status: current
   Units: milliseconds

5.9.4.  flowEndMilliseconds

   Description:
      The absolute timestamp of the last packet of this Flow.
   Abstract Data Type: dateTimeMilliseconds
   ElementId: 153
   Status: current
   Units: milliseconds

5.9.5.  flowStartMicroseconds

   Description:
      The absolute timestamp of the first packet of this Flow.
   Abstract Data Type: dateTimeMicroseconds
   ElementId: 154
   Status: current
   Units: microseconds

5.9.6.  flowEndMicroseconds

   Description:
      The absolute timestamp of the last packet of this Flow.
   Abstract Data Type: dateTimeMicroseconds
   ElementId: 155
   Status: current
   Units: microseconds

5.9.7.  flowStartNanoseconds

   Description:
      The absolute timestamp of the first packet of this Flow.
   Abstract Data Type: dateTimeNanoseconds
   ElementId: 156
   Status: current
   Units: nanoseconds

5.9.8.  flowEndNanoseconds

   Description:
      The absolute timestamp of the last packet of this Flow.
   Abstract Data Type: dateTimeNanoseconds
   ElementId: 157
   Status: current
   Units: nanoseconds

5.9.9.  flowStartDeltaMicroseconds

   Description:
      This is a relative timestamp only valid within the scope of a
      single IPFIX Message.  It contains the negative time offset of the
      first observed packet of this Flow relative to the export time
      specified in the IPFIX Message Header.
   Abstract Data Type: unsigned32
   ElementId: 158
   Status: current
   Units: microseconds
   Reference:
      See the IPFIX protocol specification [RFC5101] for the definition
      of the IPFIX Message Header.

5.9.10.  flowEndDeltaMicroseconds

   Description:
      This is a relative timestamp only valid within the scope of a
      single IPFIX Message.  It contains the negative time offset of the
      last observed packet of this Flow relative to the export time
      specified in the IPFIX Message Header.
   Abstract Data Type: unsigned32
   ElementId: 159
   Status: current
   Units: microseconds
   Reference:
      See the IPFIX protocol specification [RFC5101] for the
      definition of the IPFIX Message Header.

5.9.11.  systemInitTimeMilliseconds

   Description:
      The absolute timestamp of the last (re-)initialization of the
      IPFIX Device.
   Abstract Data Type: dateTimeMilliseconds
   ElementId: 160
   Status: current
   Units: milliseconds

5.9.12.  flowStartSysUpTime

   Description:
      The relative timestamp of the first packet of this Flow.  It
      indicates the number of milliseconds since the last
      (re-)initialization of the IPFIX Device (sysUpTime).
   Abstract Data Type: unsigned32
   ElementId: 22
   Status: current
   Units: milliseconds

5.9.13.  flowEndSysUpTime

   Description:
      The relative timestamp of the last packet of this Flow.  It
      indicates the number of milliseconds since the last
      (re-)initialization of the IPFIX Device (sysUpTime).
   Abstract Data Type: unsigned32
   ElementId: 21
   Status: current
   Units: milliseconds

5.10.  Per-Flow Counters

   Information Elements in this section are counters all having integer
   values.  Their values may change for every report they are used in.
   They cannot serve as part of a Flow Key used for mapping packets to
   Flows.  However, potentially they can be used for selecting exported
   Flows, for example, by only exporting Flows with more than a
   threshold number of observed octets.

   There are running counters and delta counters.  Delta counters are
   reset to zero each time their values are exported.  Running counters
   continue counting independently of the Exporting Process.

   There are per-Flow counters and counters related to the Metering
   Process and/or the Exporting Process.  Per-Flow counters are Flow
   properties that potentially change each time a packet belonging to
   the Flow is observed.  The set of per-Flow counters includes the
   Information Elements listed in the table below.  Counters related to
   the Metering Process and/or the Exporting Process are described in
   Section 5.3.

   +-----+---------------------------+-----+---------------------------+
   |  ID | Name                      |  ID | Name                      |
   +-----+---------------------------+-----+---------------------------+
   |   1 | octetDeltaCount           | 134 | droppedOctetTotalCount    |
   |  23 | postOctetDeltaCount       | 135 | droppedPacketTotalCount   |
   | 198 | octetDeltaSumOfSquares    |  19 | postMCastPacketDeltaCount |
   |  85 | octetTotalCount           |  20 | postMCastOctetDeltaCount  |
   | 171 | postOctetTotalCount       | 174 | postMCastPacketTotalCount |
   | 199 | octetTotalSumOfSquares    | 175 | postMCastOctetTotalCount  |
   |   2 | packetDeltaCount          | 218 | tcpSynTotalCount          |
   |  24 | postPacketDeltaCount      | 219 | tcpFinTotalCount          |
   |  86 | packetTotalCount          | 220 | tcpRstTotalCount          |
   | 172 | postPacketTotalCount      | 221 | tcpPshTotalCount          |
   | 132 | droppedOctetDeltaCount    | 222 | tcpAckTotalCount          |
   | 133 | droppedPacketDeltaCount   | 223 | tcpUrgTotalCount          |
   +-----+---------------------------+-----+---------------------------+

5.10.1.  octetDeltaCount

   Description:
      The number of octets since the previous report (if any) in
      incoming packets for this Flow at the Observation Point.  The
      number of octets includes IP header(s) and IP payload.
   Abstract Data Type: unsigned64
   Data Type Semantics: deltaCounter
   ElementId: 1
   Status: current
   Units: octets

5.10.2.  postOctetDeltaCount

   Description:
      The definition of this Information Element is identical to the
      definition of Information Element 'octetDeltaCount', except that
      it reports a potentially modified value caused by a middlebox
      function after the packet passed the Observation Point.
   Abstract Data Type: unsigned64
   Data Type Semantics: deltaCounter
   ElementId: 23
   Status: current
   Units: octets

5.10.3.  octetDeltaSumOfSquares

   Description:
      The sum of the squared numbers of octets per incoming packet since
      the previous report (if any) for this Flow at the Observation
      Point.  The number of octets includes IP header(s) and IP payload.
   Abstract Data Type: unsigned64
   ElementId: 198
   Status: current

5.10.4.  octetTotalCount

   Description:
      The total number of octets in incoming packets for this Flow at
      the Observation Point since the Metering Process
      (re-)initialization for this Observation Point.  The number
      of octets includes IP header(s) and IP payload.
   Abstract Data Type: unsigned64
   Data Type Semantics: totalCounter
   ElementId: 85
   Status: current
   Units: octets

5.10.5.  postOctetTotalCount

   Description:
      The definition of this Information Element is identical to the
      definition of Information Element 'octetTotalCount', except that
      it reports a potentially modified value caused by a middlebox
      function after the packet passed the Observation Point.
   Abstract Data Type: unsigned64
   Data Type Semantics: totalCounter
   ElementId: 171
   Status: current
   Units: octets

5.10.6.  octetTotalSumOfSquares

   Description:
      The total sum of the squared numbers of octets in incoming packets
      for this Flow at the Observation Point since the Metering Process
      (re-)initialization for this Observation Point.  The number of
      octets includes IP header(s) and IP payload.
   Abstract Data Type: unsigned64
   ElementId: 199
   Status: current
   Units: octets

5.10.7.  packetDeltaCount

   Description:
      The number of incoming packets since the previous report (if any)
      for this Flow at the Observation Point.

   Abstract Data Type: unsigned64
   Data Type Semantics: deltaCounter
   ElementId: 2
   Status: current
   Units: packets

5.10.8.  postPacketDeltaCount

   Description:
      The definition of this Information Element is identical to the
      definition of Information Element 'packetDeltaCount', except that
      it reports a potentially modified value caused by a middlebox
      function after the packet passed the Observation Point.
   Abstract Data Type: unsigned64
   Data Type Semantics: deltaCounter
   ElementId: 24
   Status: current
   Units: packets

5.10.9.  packetTotalCount

   Description:
      The total number of incoming packets for this Flow at the
      Observation Point since the Metering Process (re-)initialization
      for this Observation Point.
   Abstract Data Type: unsigned64
   Data Type Semantics: totalCounter
   ElementId: 86
   Status: current
   Units: packets

5.10.10.  postPacketTotalCount

   Description:
      The definition of this Information Element is identical to the
      definition of Information Element 'packetTotalCount', except that
      it reports a potentially modified value caused by a middlebox
      function after the packet passed the Observation Point.
   Abstract Data Type: unsigned64
   Data Type Semantics: totalCounter
   ElementId: 172
   Status: current
   Units: packets

5.10.11.  droppedOctetDeltaCount

   Description:
      The number of octets since the previous report (if any) in packets
      of this Flow dropped by packet treatment.  The number of octets
      includes IP header(s) and IP payload.
   Abstract Data Type: unsigned64
   Data Type Semantics: deltaCounter
   ElementId: 132
   Status: current
   Units: octets

5.10.12.  droppedPacketDeltaCount

   Description:
      The number of packets since the previous report (if any) of this
      Flow dropped by packet treatment.
   Abstract Data Type: unsigned64
   Data Type Semantics: deltaCounter
   ElementId: 133
   Status: current
   Units: packets

5.10.13.  droppedOctetTotalCount

   Description:
      The total number of octets in packets of this Flow dropped by
      packet treatment since the Metering Process (re-)initialization
      for this Observation Point.  The number of octets includes IP
      header(s) and IP payload.
   Abstract Data Type: unsigned64
   Data Type Semantics: totalCounter
   ElementId: 134
   Status: current
   Units: octets

5.10.14.  droppedPacketTotalCount

   Description:
      The number of packets of this Flow dropped by packet treatment
      since the Metering Process (re-)initialization for this
      Observation Point.
   Abstract Data Type: unsigned64
   Data Type Semantics: totalCounter
   ElementId: 135
   Status: current
   Units: packets

5.10.15.  postMCastPacketDeltaCount

   Description:
      The number of outgoing multicast packets since the previous report
      (if any) sent for packets of this Flow by a multicast daemon
      within the Observation Domain.  This property cannot necessarily
      be observed at the Observation Point, but may be retrieved by
      other means.
   Abstract Data Type: unsigned64
   Data Type Semantics: deltaCounter
   ElementId: 19
   Status: current
   Units: packets

5.10.16.  postMCastOctetDeltaCount

   Description:
      The number of octets since the previous report (if any) in
      outgoing multicast packets sent for packets of this Flow by a
      multicast daemon within the Observation Domain.  This property
      cannot necessarily be observed at the Observation Point, but may
      be retrieved by other means.  The number of octets includes IP
      header(s) and IP payload.
   Abstract Data Type: unsigned64
   Data Type Semantics: deltaCounter
   ElementId: 20
   Status: current
   Units: octets

5.10.17.  postMCastPacketTotalCount

   Description:
      The total number of outgoing multicast packets sent for packets of
      this Flow by a multicast daemon within the Observation Domain
      since the Metering Process (re-)initialization.  This property
      cannot necessarily be observed at the Observation Point, but may
      be retrieved by other means.
   Abstract Data Type: unsigned64
   Data Type Semantics: totalCounter
   ElementId: 174
   Status: current
   Units: packets

5.10.18.  postMCastOctetTotalCount

   Description:
      The total number of octets in outgoing multicast packets sent for
      packets of this Flow by a multicast daemon in the Observation
      Domain since the Metering Process (re-)initialization.  This
      property cannot necessarily be observed at the Observation Point,
      but may be retrieved by other means.  The number of octets
      includes IP header(s) and IP payload.
   Abstract Data Type: unsigned64
   Data Type Semantics: totalCounter
   ElementId: 175
   Status: current
   Units: octets

5.10.19.  tcpSynTotalCount

   Description:
      The total number of packets of this Flow with TCP "Synchronize
      sequence numbers" (SYN) flag set.
   Abstract Data Type: unsigned64
   Data Type Semantics: totalCounter
   ElementId: 218
   Status: current
   Units: packets
   Reference:
      See RFC 793 for the definition of the TCP SYN flag.

5.10.20.  tcpFinTotalCount

   Description:
      The total number of packets of this Flow with TCP "No more data
      from sender" (FIN) flag set.
   Abstract Data Type: unsigned64
   Data Type Semantics: totalCounter
   ElementId: 219
   Status: current
   Units: packets
   Reference:
      See RFC 793 for the definition of the TCP FIN flag.

5.10.21.  tcpRstTotalCount

   Description:
      The total number of packets of this Flow with TCP "Reset the
      connection" (RST) flag set.
   Abstract Data Type: unsigned64
   Data Type Semantics: totalCounter
   ElementId: 220
   Status: current
   Units: packets
   Reference:
      See RFC 793 for the definition of the TCP RST flag.

5.10.22.  tcpPshTotalCount

   Description:
      The total number of packets of this Flow with TCP "Push Function"
      (PSH) flag set.
   Abstract Data Type: unsigned64
   Data Type Semantics: totalCounter
   ElementId: 221
   Status: current
   Units: packets
   Reference:
      See RFC 793 for the definition of the TCP PSH flag.

5.10.23.  tcpAckTotalCount

   Description:
      The total number of packets of this Flow with TCP "Acknowledgment
      field significant" (ACK) flag set.
   Abstract Data Type: unsigned64
   Data Type Semantics: totalCounter
   ElementId: 222
   Status: current
   Units: packets
   Reference:
      See RFC 793 for the definition of the TCP ACK flag.

5.10.24.  tcpUrgTotalCount

   Description:
      The total number of packets of this Flow with TCP "Urgent Pointer
      field significant" (URG) flag set.
   Abstract Data Type: unsigned64
   Data Type Semantics: totalCounter
   ElementId: 223
   Status: current
   Units: packets
   Reference:
      See RFC 793 for the definition of the TCP URG flag.

5.11.  Miscellaneous Flow Properties

   Information Elements in this section describe properties of Flows
   that are related to Flow start, Flow duration, and Flow termination,
   but they are not timestamps as Information Elements in Section 5.9.

   +-----+---------------------------+-----+---------------------------+
   |  ID | Name                      |  ID | Name                      |
   +-----+---------------------------+-----+---------------------------+
   |  36 | flowActiveTimeout         | 161 | flowDurationMilliseconds  |
   |  37 | flowIdleTimeout           | 162 | flowDurationMicroseconds  |
   | 136 | flowEndReason             |  61 | flowDirection             |
   +-----+---------------------------+-----+---------------------------+

5.11.1.  flowActiveTimeout

   Description:
      The number of seconds after which an active Flow is timed out
      anyway, even if there is still a continuous flow of packets.
   Abstract Data Type: unsigned16
   ElementId: 36
   Status: current
   Units: seconds

5.11.2.  flowIdleTimeout

   Description:
      A Flow is considered to be timed out if no packets belonging to
      the Flow have been observed for the number of seconds specified by
      this field.
   Abstract Data Type: unsigned16
   ElementId: 37
   Status: current
   Units: seconds

5.11.3.  flowEndReason

   Description:
      The reason for Flow termination.  The range of values includes the
      following:

      0x01: idle timeout
            The Flow was terminated because it was considered to be
            idle.

      0x02: active timeout
            The Flow was terminated for reporting purposes while it was
            still active, for example, after the maximum lifetime of
            unreported Flows was reached.

      0x03: end of Flow detected
            The Flow was terminated because the Metering Process
            detected signals indicating the end of the Flow, for
            example, the TCP FIN flag.

      0x04: forced end
            The Flow was terminated because of some external event, for
            example, a shutdown of the Metering Process initiated by a
            network management application.

      0x05: lack of resources
            The Flow was terminated because of lack of resources
            available to the Metering Process and/or the Exporting
            Process.

   Abstract Data Type: unsigned8
   Data Type Semantics: identifier
   ElementId: 136
   Status: current

5.11.4.  flowDurationMilliseconds

   Description:
      The difference in time between the first observed packet of this
      Flow and the last observed packet of this Flow.
   Abstract Data Type: unsigned32
   ElementId: 161
   Status: current
   Units: milliseconds

5.11.5.  flowDurationMicroseconds

   Description:
      The difference in time between the first observed packet of this
      Flow and the last observed packet of this Flow.
   Abstract Data Type: unsigned32
   ElementId: 162
   Status: current
   Units: microseconds

5.11.6.  flowDirection

   Description:
      The direction of the Flow observed at the Observation Point.
      There are only two values defined.

      0x00: ingress flow
      0x01: egress flow

   Abstract Data Type: unsigned8
   Data Type Semantics: identifier
   ElementId: 61
   Status: current

5.12.  Padding

   This section contains a single Information Element that can be used
   for padding of Flow Records.

   IPFIX implementations may wish to align Information Elements within
   Data Records or to align entire Data Records to 4-octet or 8-octet
   boundaries.  This can be achieved by including one or more
   paddingOctets Information Elements in a Data Record.

   +-----+---------------------------+-----+---------------------------+
   |  ID | Name                      |  ID | Name                      |
   +-----+---------------------------+-----+---------------------------+
   | 210 | paddingOctets             |     |                           |
   +-----+---------------------------+-----+---------------------------+

5.12.1.  paddingOctets

   Description:
      The value of this Information Element is always a sequence of 0x00
      values.
   Abstract Data Type: octetArray
   ElementId: 210
   Status: current

6.  Extending the Information Model

   A key requirement for IPFIX is to allow for extending the set of
   Information Elements that are reported.  This section defines the
   mechanism for extending this set.

   Extension can be done by defining new Information Elements.  Each new
   Information Element MUST be assigned a unique Information Element
   identifier as part of its definition.  These unique Information
   Element identifiers are the connection between the record structure
   communicated by the protocol using Templates and a consuming
   application.  For generally applicable Information Elements, using
   IETF and IANA mechanisms to extend the information model is
   RECOMMENDED.

   Names of new Information Elements SHOULD be chosen according to the
   naming conventions given in Section 2.3.

   For extensions, the type space defined in Section 3 can be used.  If
   required, new abstract data types can be added.  New abstract data
   types MUST be defined in IETF Standards Track documents.

   Enterprises may wish to define Information Elements without
   registering them with IANA.  IPFIX explicitly supports
   enterprise-specific Information Elements.  Enterprise-specific
   Information Elements are described in Sections 2.1 and 4.

   However, before creating enterprise-specific Information Elements,
   the general applicability of such Information Elements should be
   considered.  IPFIX does not support enterprise-specific abstract data
   types.

7.  IANA Considerations

7.1.  IPFIX Information Elements

   This document specifies an initial set of IPFIX Information Elements.
   The list of these Information Elements with their identifiers is
   given in Section 4.  The Internet Assigned Numbers Authority (IANA)
   has created a new registry for IPFIX Information Element identifiers
   and filled it with the initial list in Section 4.

   New assignments for IPFIX Information Elements will be administered
   by IANA through Expert Review [RFC2434], i.e., review by one of a
   group of experts designated by an IETF Area Director.  The group of
   experts MUST check the requested Information Element for completeness
   and accuracy of the description and for correct naming according to
   the naming conventions in Section 2.3.  Requests for Information
   Elements that duplicate the functionality of existing Information
   Elements SHOULD be declined.  The smallest available identifier
   SHOULD be assigned to a new Information Element.

   The specification of new IPFIX Information Elements MUST use the
   template specified in Section 2.1 and MUST be published using a
   well-established and persistent publication medium.  The experts will
   initially be drawn from the Working Group Chairs and document editors
   of the IPFIX and PSAMP Working Groups.

7.2.  MPLS Label Type Identifier

   Information Element #46, named mplsTopLabelType, carries MPLS label
   types.  Values for 5 different types have initially been defined.
   For ensuring extensibility of this information, IANA has created a
   new registry for MPLS label types and filled it with the initial list
   from the description Information Element #46, mplsTopLabelType.

   New assignments for MPLS label types will be administered by IANA
   through Expert Review [RFC2434], i.e., review by one of a group of
   experts designated by an IETF Area Director.  The group of experts
   must double check the label type definitions with already defined
   label types for completeness, accuracy, and redundancy.  The
   specification of new MPLS label types MUST be published using a
   well-established and persistent publication medium.

7.3.  XML Namespace and Schema

   Appendix B defines an XML schema for IPFIX Information Element
   definitions.  All Information Elements specified in this document are
   defined by the XML specification in Appendix A that is a valid XML
   record according to the schema in Appendix B.  This schema may also
   be used for specifying further Information Elements in future
   extensions of the IPFIX information model in a machine-readable way.

   Appendix B uses URNs to describe an XML namespace and an XML schema
   for IPFIX Information Elements conforming to a registry mechanism
   described in [RFC3688].  Two URI assignments have been made.

   1.  Registration for the IPFIX information model namespace
       *  URI: urn:ietf:params:xml:ns:ipfix-info-15
       *  Registrant Contact: IETF IPFIX Working Group <ipfix@ietf.org>,
          as designated by the IESG <iesg@ietf.org>.
       *  XML: None.  Namespace URIs do not represent an XML.

   2.  Registration for the IPFIX information model schema
       *  URI: urn:ietf:params:xml:schema:ipfix-info-15
       *  Registrant Contact: IETF IPFIX Working Group <ipfix@ietf.org>,
          as designated by the IESG <iesg@ietf.org>.
       *  XML: See Appendix B of this document.

8.  Security Considerations

   The IPFIX information model itself does not directly introduce
   security issues.  Rather, it defines a set of attributes that may for
   privacy or business issues be considered sensitive information.

   For example, exporting values of header fields may make attacks
   possible for the receiver of this information, which would otherwise
   only be possible for direct observers of the reported Flows along the
   data path.

   The underlying protocol used to exchange the information described
   here must therefore apply appropriate procedures to guarantee the
   integrity and confidentiality of the exported information.  Such
   protocols are defined in separate documents, specifically the IPFIX
   protocol document [RFC5101].

   This document does not specify any Information Element carrying
   keying material.  If future extensions will do so, then appropriate
   precautions need to be taken for properly protecting such sensitive
   information.

9.  Acknowledgements

   The editors thank Paul Callato for creating the initial version of
   this document, and Thomas Dietz for developing the XSLT scripts that
   generate large portions of the text part of this document from the
   XML appendices.

10.  References

10.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC5101]  Claise, B., "Specification of the IPFIX Protocol for the
              Exchange", RFC 5101, November 2007.

10.2.  Informative References

   [IEEE.754.1985]
              Institute of Electrical and Electronics Engineers,
              "Standard for Binary Floating-Point Arithmetic", IEEE
              Standard 754, August 1985.

   [IEEE.802-11.1999]
              "Information technology - Telecommunications and
              information exchange between systems - Local and
              metropolitan area networks - Specific requirements - Part
              11: Wireless LAN Medium Access Control (MAC) and Physical
              Layer (PHY) specifications", IEEE Standard 802.11, 1999,
              <http://standards.ieee.org/getieee802/download/802.11-
              1999.pdF>.

   [IEEE.802-1Q.2003]
              Institute of Electrical and Electronics Engineers, "Local
              and Metropolitan Area Networks: Virtual Bridged Local Area
              Networks", IEEE Standard 802.1Q, March 2003.

   [IEEE.802-3.2002]
              "Information technology - Telecommunications and
              information exchange between systems - Local and
              metropolitan area networks - Specific requirements - Part
              3: Carrier sense multiple access with collision detection
              (CSMA/CD) access method and physical layer
              specifications", IEEE Standard 802.3, September 2002.

   [ISO.10646-1.1993]
              International Organization for Standardization,
              "Information Technology - Universal Multiple-octet coded
              Character Set (UCS) - Part 1: Architecture and Basic
              Multilingual Plane", ISO Standard 10646-1, May 1993.

   [ISO.646.1991]
              International Organization for Standardization,
              "Information technology - ISO 7-bit coded character set
              for information interchange", ISO Standard 646, 1991.

   [RFC0768]  Postel, J., "User Datagram Protocol", STD 6, RFC 768,
              August 1980.

   [RFC0791]  Postel, J., "Internet Protocol", STD 5, RFC 791, September
              1981.

   [RFC0792]  Postel, J., "Internet Control Message Protocol", STD 5,
              RFC 792, September 1981.

   [RFC0793]  Postel, J., "Transmission Control Protocol", STD 7, RFC
              793, September 1981.

   [RFC1108]  Kent, S., "U.S. Department of Defense Security Options for
              the Internet Protocol", RFC 1108, November 1991.

   [RFC1112]  Deering, S., "Host extensions for IP multicasting", STD 5,
              RFC 1112, August 1989.

   [RFC1191]  Mogul, J. and S. Deering, "Path MTU discovery", RFC 1191,
              November 1990.

   [RFC1323]  Jacobson, V., Braden, R., and D. Borman, "TCP Extensions
              for High Performance", RFC 1323, May 1992.

   [RFC1385]  Wang, Z., "EIP: The Extended Internet Protocol", RFC 1385,
              November 1992.

   [RFC1812]  Baker, F., Ed., "Requirements for IP Version 4 Routers",
              RFC 1812, June 1995.

   [RFC1930]  Hawkinson, J. and T. Bates, "Guidelines for creation,
              selection, and registration of an Autonomous System (AS)",
              BCP 6, RFC 1930, March 1996.

   [RFC2113]  Katz, D., "IP Router Alert Option", RFC 2113, February
              1997.

   [RFC2434]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 2434,
              October 1998.

   [RFC2460]  Deering, S. and R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", RFC 2460, December 1998.

   [RFC2578]  McCloghrie, K., Perkins, D., and J. Schoenwaelder,
              "Structure of Management Information Version 2 (SMIv2)",
              STD 58, RFC 2578, April 1999.

   [RFC2629]  Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629,
              June 1999.

   [RFC2675]  Borman, D., Deering, S., and R. Hinden, "IPv6 Jumbograms",
              RFC 2675, August 1999.

   [RFC2863]  McCloghrie, K. and F. Kastenholz, "The Interfaces Group
              MIB", RFC 2863, June 2000.

   [RFC3031]  Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
              Label Switching Architecture", RFC 3031, January 2001.

   [RFC3032]  Rosen, E., Tappan, D., Fedorkow, G., Rekhter, Y.,
              Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack
              Encoding", RFC 3032, January 2001.

   [RFC3193]  Patel, B., Aboba, B., Dixon, W., Zorn, G., and S. Booth,
              "Securing L2TP using IPsec", RFC 3193, November 2001.

   [RFC3234]  Carpenter, B. and S. Brim, "Middleboxes: Taxonomy and
              Issues", RFC 3234, February 2002.

   [RFC3260]  Grossman, D., "New Terminology and Clarifications for
              Diffserv", RFC 3260, April 2002.

   [RFC3270]  Le Faucheur, F., Wu, L., Davie, B., Davari, S., Vaananen,
              P., Krishnan, R., Cheval, P., and J. Heinanen, "Multi-
              Protocol Label Switching (MPLS) Support of Differentiated
              Services", RFC 3270, May 2002.

   [RFC3376]  Cain, B., Deering, S., Kouvelas, I., Fenner, B., and A.
              Thyagarajan, "Internet Group Management Protocol, Version
              3", RFC 3376, October 2002.

   [RFC3444]  Pras, A. and J. Schoenwaelder, "On the Difference between
              Information Models and Data Models", RFC 3444, January
              2003.

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              January 2004.

   [RFC3954]  Claise, B., Ed., "Cisco Systems NetFlow Services Export
              Version 9", RFC 3954, October 2004.

   [RFC4271]  Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
              Border Gateway Protocol 4 (BGP-4)", RFC 4271, January
              2006.

   [RFC4291]  Hinden, R. and S. Deering, "IP Version 6 Addressing
              Architecture", RFC 4291, February 2006.

   [RFC4302]  Kent, S., "IP Authentication Header", RFC 4302, December
              2005.

   [RFC4303]  Kent, S., "IP Encapsulating Security Payload (ESP)", RFC
              4303, December 2005.

   [RFC4364]  Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
              Networks (VPNs)", RFC 4364, February 2006.

   [RFC4382]  Nadeau, T., Ed., and H. van der Linde, Ed., "MPLS/BGP
              Layer 3 Virtual Private Network (VPN) Management
              Information Base", RFC 4382, February 2006.

   [RFC4443]  Conta, A., Deering, S., and M. Gupta, Ed., "Internet
              Control Message Protocol (ICMPv6) for the Internet
              Protocol Version 6 (IPv6) Specification", RFC 4443, March
              2006.

   [RFC4960]  Stewart, R., Ed., "Stream Control Transmission Protocol",
              RFC 4960, September 2007.

   [RFC5036]  Andersson, L., Ed., Minei, I., Ed., and B. Thomas, Ed.,
              "LDP Specification", RFC 5036, October 2007.

Appendix A.  XML Specification of IPFIX Information Elements

   This appendix contains a machine-readable description of the IPFIX
   information model coded in XML.  Note that this appendix is of
   informational nature, while the text in Section 4 (generated from
   this appendix) is normative.

   Using a machine-readable syntax for the information model enables the
   creation of IPFIX-aware tools that can automatically adapt to
   extensions to the information model, by simply reading updated
   information model specifications.

   The wide availability of XML-aware tools and libraries for client
   devices is a primary consideration for this choice.  In particular,
   libraries for parsing XML documents are readily available.  Also,
   mechanisms such as the Extensible Stylesheet Language (XSL) allow for
   transforming a source XML document into other documents.  This
   document was authored in XML and transformed according to [RFC2629].

   It should be noted that the use of XML in Exporters, Collectors, or
   other tools is not mandatory for the deployment of IPFIX.  In
   particular, Exporting Processes do not produce or consume XML as part
   of their operation.  It is expected that IPFIX Collectors MAY take
   advantage of the machine readability of the information model vs.
   hard coding their behavior or inventing proprietary means for
   accommodating extensions.

   <?xml version="1.0" encoding="UTF-8"?>

   <fieldDefinitions xmlns="urn:ietf:params:xml:ns:ipfix-info"
                xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                xsi:schemaLocation="urn:ietf:params:xml:ns:ipfix-info
                ipfix-info.xsd">

     <field name="lineCardId" dataType="unsigned32"
            group="scope"
            dataTypeSemantics="identifier"
            elementId="141" applicability="option" status="current">
       <description>
         <paragraph>
           An identifier of a line card that is unique per IPFIX
           Device hosting an Observation Point.  Typically, this
           Information Element is used for limiting the scope
           of other Information Elements.
         </paragraph>
       </description>
     </field>
     <field name="portId" dataType="unsigned32"
            group="scope"
            dataTypeSemantics="identifier"
            elementId="142" applicability="option" status="current">
       <description>
         <paragraph>
           An identifier of a line port that is unique per IPFIX
           Device hosting an Observation Point.  Typically, this
           Information Element is used for limiting the scope
           of other Information Elements.
         </paragraph>
       </description>
     </field>

     <field name="ingressInterface" dataType="unsigned32"
            group="scope"
            dataTypeSemantics="identifier"
            elementId="10" applicability="all" status="current">
       <description>
         <paragraph>
           The index of the IP interface where packets of this Flow
           are being received.  The value matches the value of managed
           object 'ifIndex' as defined in RFC 2863.
           Note that ifIndex values are not assigned statically to an
           interface and that the interfaces may be renumbered every
           time the device's management system is re-initialized, as
           specified in RFC 2863.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 2863 for the definition of the ifIndex object.
         </paragraph>
       </reference>
     </field>

     <field name="egressInterface" dataType="unsigned32"
            group="scope"
            dataTypeSemantics="identifier"
            elementId="14" applicability="all" status="current">
       <description>
         <paragraph>
           The index of the IP interface where packets of
           this Flow are being sent.  The value matches the value of
           managed object 'ifIndex' as defined in RFC 2863.
           Note that ifIndex values are not assigned statically to an
           interface and that the interfaces may be renumbered every
           time the device's management system is re-initialized, as
           specified in RFC 2863.

         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 2863 for the definition of the ifIndex object.
         </paragraph>
       </reference>
     </field>

     <field name="meteringProcessId" dataType="unsigned32"
            group="scope"
            dataTypeSemantics="identifier"
            elementId="143" applicability="option" status="current">
       <description>
         <paragraph>
           An identifier of a Metering Process that is unique per
           IPFIX Device.  Typically, this Information Element is used
           for limiting the scope of other Information Elements.
           Note that process identifiers are typically assigned
           dynamically.
           The Metering Process may be re-started with a different ID.
         </paragraph>
       </description>
     </field>

     <field name="exportingProcessId" dataType="unsigned32"
            group="scope"
            dataTypeSemantics="identifier"
            elementId="144" applicability="option" status="current">
       <description>
         <paragraph>
           An identifier of an Exporting Process that is unique per
           IPFIX Device.  Typically, this Information Element is used
           for limiting the scope of other Information Elements.
           Note that process identifiers are typically assigned
           dynamically.  The Exporting Process may be re-started
           with a different ID.
         </paragraph>
       </description>
     </field>

     <field name="flowId" dataType="unsigned64"
            group="scope"
            dataTypeSemantics="identifier"
            elementId="148" applicability="option" status="current">
       <description>
         <paragraph>
           An identifier of a Flow that is unique within an Observation
           Domain.  This Information Element can be used to distinguish
           between different Flows if Flow Keys such as IP addresses and
           port numbers are not reported or are reported in separate
           records.
         </paragraph>
       </description>
     </field>

     <field name="templateId" dataType="unsigned16"
            group="scope"
            dataTypeSemantics="identifier"
            elementId="145" applicability="option" status="current">
       <description>
         <paragraph>
           An identifier of a Template that is locally unique within a
           combination of a Transport session and an Observation Domain.
         </paragraph>
         <paragraph>
           Template IDs 0-255 are reserved for Template Sets, Options
           Template Sets, and other reserved Sets yet to be created.
           Template IDs of Data Sets are numbered from 256 to 65535.
         </paragraph>
         <paragraph>
           Typically, this Information Element is used for limiting
           the scope of other Information Elements.
           Note that after a re-start of the Exporting Process Template
           identifiers may be re-assigned.
         </paragraph>
       </description>
     </field>

     <field name="observationDomainId" dataType="unsigned32"
            group="scope"
            dataTypeSemantics="identifier"
            elementId="149" applicability="option" status="current">
       <description>
         <paragraph>
           An identifier of an Observation Domain that is locally
           unique to an Exporting Process.  The Exporting Process uses
           the Observation Domain ID to uniquely identify to the
           Collecting Process the Observation Domain where Flows
           were metered.  It is RECOMMENDED that this identifier is
           also unique per IPFIX Device.
         </paragraph>
         <paragraph>
           A value of 0 indicates that no specific Observation Domain
           is identified by this Information Element.
         </paragraph>
         <paragraph>
           Typically, this Information Element is used for limiting
           the scope of other Information Elements.
         </paragraph>
       </description>
     </field>

     <field name="observationPointId" dataType="unsigned32"
            group="scope"
            dataTypeSemantics="identifier"
            elementId="138" applicability="option" status="current">
       <description>
         <paragraph>
         An identifier of an Observation Point that is unique per
         Observation Domain.  It is RECOMMENDED that this identifier is
         also unique per IPFIX Device.  Typically, this Information
         Element is used for limiting the scope of other Information
         Elements.
         </paragraph>
       </description>
     </field>
     <field name="commonPropertiesId" dataType="unsigned64"
            group="scope"
            dataTypeSemantics="identifier"
            elementId="137" applicability="option" status="current">
       <description>
         <paragraph>
           An identifier of a set of common properties that is
           unique per Observation Domain and Transport Session.
           Typically, this Information Element is used to link to
           information reported in separate Data Records.
         </paragraph>
       </description>
     </field>

     <field name="exporterIPv4Address" dataType="ipv4Address"
            dataTypeSemantics="identifier"
            group="config"
            elementId="130" applicability="all" status="current">
       <description>
         <paragraph>
         The IPv4 address used by the Exporting Process.  This is used
         by the Collector to identify the Exporter in cases where the
         identity of the Exporter may have been obscured by the use of
         a proxy.
         </paragraph>
       </description>
     </field>
     <field name="exporterIPv6Address" dataType="ipv6Address"
            dataTypeSemantics="identifier"
            group="config"
            elementId="131" applicability="all" status="current">
       <description>
         <paragraph>
         The IPv6 address used by the Exporting Process.  This is used
         by the Collector to identify the Exporter in cases where the
         identity of the Exporter may have been obscured by the use of
         a proxy.
         </paragraph>
       </description>
     </field>

     <field name="exporterTransportPort" dataType="unsigned16"
            group="config"
            dataTypeSemantics="identifier"
            elementId="217" applicability="all" status="current">
       <description>
         <paragraph>
         The source port identifier from which the Exporting
         Process sends Flow information.  For the transport protocols
         UDP, TCP, and SCTP, this is the source port number.
         This field MAY also be used for future transport protocols
         that have 16-bit source port identifiers.  This field may
         be useful for distinguishing multiple Exporting Processes
         that use the same IP address.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 768 for the definition of the UDP
         source port field.
         See RFC 793 for the definition of the TCP
         source port field.
         See RFC 4960 for the definition of SCTP.
         </paragraph>
         <paragraph>
         Additional information on defined UDP and TCP port numbers can
         be found at http://www.iana.org/assignments/port-numbers.
         </paragraph>
       </reference>
     </field>

     <field name="collectorIPv4Address" dataType="ipv4Address"
            dataTypeSemantics="identifier"
            group="config"
            elementId="211" applicability="all" status="current">
       <description>
         <paragraph>
         An IPv4 address to which the Exporting Process sends Flow
         information.
         </paragraph>
       </description>
     </field>

     <field name="collectorIPv6Address" dataType="ipv6Address"
            dataTypeSemantics="identifier"
            group="config"
            elementId="212" applicability="all" status="current">
       <description>
         <paragraph>
         An IPv6 address to which the Exporting Process sends Flow
         information.
         </paragraph>
       </description>
     </field>

     <field name="collectorInterface" dataType="unsigned32"
            group="config"
            dataTypeSemantics="identifier"
            elementId="213" applicability="all" status="current">
       <description>
         <paragraph>
           The index of the interface from which IPFIX Messages sent
           by the Exporting Process to a Collector leave the IPFIX
           Device.  The value matches the value of
           managed object 'ifIndex' as defined in RFC 2863.
           Note that ifIndex values are not assigned statically to an
           interface and that the interfaces may be renumbered every
           time the device's management system is re-initialized, as
           specified in RFC 2863.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 2863 for the definition of the ifIndex object.
         </paragraph>
       </reference>
     </field>

     <field name="collectorProtocolVersion" dataType="unsigned8"
            dataTypeSemantics="identifier"
            group="config"
            elementId="214" applicability="all" status="current">
       <description>
         <paragraph>
           The protocol version used by the Exporting Process for
           sending Flow information.  The protocol version is given
           by the value of the Version Number field in the Message
           Header.
         </paragraph>
         <paragraph>
           The protocol version is 10 for IPFIX and 9 for NetFlow
           version 9.
           A value of 0 indicates that no export protocol is in use.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See the IPFIX protocol specification [RFC5101] for the
         definition of the IPFIX Message Header.
         </paragraph>
         <paragraph>
         See RFC 3954 for the definition of the NetFlow
         version 9 message header.
         </paragraph>
       </reference>
     </field>

     <field name="collectorTransportProtocol" dataType="unsigned8"
            group="config"
            dataTypeSemantics="identifier"
            elementId="215" applicability="all" status="current">
       <description>
         <paragraph>
         The value of the protocol number used by the Exporting Process
         for sending Flow information.
         The protocol number identifies the IP packet payload type.
         Protocol numbers are defined in the IANA Protocol Numbers
         registry.
         </paragraph>

         <paragraph>
         In Internet Protocol version 4 (IPv4), this is carried in the
         Protocol field.  In Internet Protocol version 6 (IPv6), this
         is carried in the Next Header field in the last extension
         header of the packet.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 791 for the specification of the IPv4
         protocol field.

         See RFC 2460 for the specification of the IPv6
         protocol field.
         See the list of protocol numbers assigned by IANA at
         http://www.iana.org/assignments/protocol-numbers.
         </paragraph>
       </reference>
     </field>

     <field name="collectorTransportPort" dataType="unsigned16"
            group="config"
            dataTypeSemantics="identifier"
            elementId="216" applicability="all" status="current">
       <description>
         <paragraph>
         The destination port identifier to which the Exporting
         Process sends Flow information.  For the transport protocols
         UDP, TCP, and SCTP, this is the destination port number.
         This field MAY also be used for future transport protocols
         that have 16-bit source port identifiers.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 768 for the definition of the UDP
         destination port field.
         See RFC 793 for the definition of the TCP
         destination port field.
         See RFC 4960 for the definition of SCTP.
         </paragraph>
         <paragraph>
         Additional information on defined UDP and TCP port numbers can
         be found at http://www.iana.org/assignments/port-numbers.
         </paragraph>
       </reference>
     </field>

     <field name="flowKeyIndicator" dataType="unsigned64"
            dataTypeSemantics="flags"
            group="config"
            elementId="173" applicability="all" status="current">
       <description>
         <paragraph>
         This set of bit fields is used for marking the Information
         Elements of a Data Record that serve as Flow Key.  Each bit
         represents an Information Element in the Data Record with
         the n-th bit representing the n-th Information Element.
         A bit set to value 1 indicates that the corresponding
         Information Element is a Flow Key of the reported Flow.

         A bit set to value 0 indicates that this is not the case.
         </paragraph>
         <paragraph>
         If the Data Record contains more than 64 Information Elements,
         the corresponding Template SHOULD be designed such that all
         Flow Keys are among the first 64 Information Elements, because
         the flowKeyIndicator only contains 64 bits.  If the Data Record
         contains less than 64 Information Elements, then the bits in
         the flowKeyIndicator for which no corresponding Information
         Element exists MUST have the value 0.
         </paragraph>
       </description>
     </field>

     <field name="exportedMessageTotalCount" dataType="unsigned64"
            dataTypeSemantics="totalCounter"
            group="processCounter"
            elementId="41" applicability="data" status="current">
       <description>
         <paragraph>
           The total number of IPFIX Messages that the Exporting Process
           sent since the Exporting Process (re-)initialization to the
           Collecting Process receiving a report that contains this
           Information Element.
           The reported number excludes the IPFIX Message that carries
           the counter value.
         </paragraph>
       </description>
       <units>messages</units>
     </field>

     <field name="exportedOctetTotalCount" dataType="unsigned64"
            dataTypeSemantics="totalCounter"
            group="processCounter"
            elementId="40" applicability="data" status="current">
       <description>
         <paragraph>
           The total number of octets that the Exporting Process
           successfully sent since the Exporting Process
           (re-)initialization to the Collecting Process receiving a
           report that contains this Information Element.  The value
           of this Information Element is calculated by summing up
           the IPFIX Message Header length values of all IPFIX Messages
           that were successfully sent to the Collecting Process
           receiving a report that contains this Information Element.
           The reported number excludes octets in the IPFIX Message
           that carries the counter value.
         </paragraph>
       </description>
       <units>octets</units>
     </field>

     <field name="exportedFlowRecordTotalCount" dataType="unsigned64"
            group="processCounter"
            dataTypeSemantics="totalCounter"
            elementId="42" applicability="data" status="current">
       <description>
         <paragraph>
           The total number of Flow Records that the Exporting
           Process successfully sent as Data Records since the Exporting
           Process (re-)initialization to the Collecting Process
           receiving a report that contains this Information Element.
           The reported number excludes Flow Records in the IPFIX
           Message that carries the counter value.
         </paragraph>
       </description>
       <units>flows</units>
     </field>

     <field name="observedFlowTotalCount" dataType="unsigned64"
            dataTypeSemantics="totalCounter"
            group="processCounter"
            elementId="163" applicability="data" status="current">
       <description>
         <paragraph>
         The total number of Flows observed in the Observation Domain
         since the Metering Process (re-)initialization for this
         Observation Point.
         </paragraph>
       </description>
       <units>flows</units>
     </field>

     <field name="ignoredPacketTotalCount" dataType="unsigned64"
            dataTypeSemantics="totalCounter"
            group="processCounter"
            elementId="164" applicability="data" status="current">
       <description>
         <paragraph>
            The total number of observed IP packets that the
            Metering Process did not process since the
            (re-)initialization of the Metering Process.
         </paragraph>
       </description>
       <units>packets</units>
     </field>
     <field name="ignoredOctetTotalCount" dataType="unsigned64"
            dataTypeSemantics="totalCounter"
            group="processCounter"
            elementId="165" applicability="data" status="current">
       <description>
         <paragraph>
            The total number of octets in observed IP packets
            (including the IP header) that the Metering Process
            did not process since the (re-)initialization of the
            Metering Process.
         </paragraph>
       </description>
       <units>octets</units>
     </field>

     <field name="notSentFlowTotalCount" dataType="unsigned64"
            dataTypeSemantics="totalCounter"
            group="processCounter"
            elementId="166" applicability="data" status="current">
       <description>
         <paragraph>
            The total number of Flow Records that were generated by the
            Metering Process and dropped by the Metering Process or
            by the Exporting Process instead of being sent to the
            Collecting Process.  There are several potential reasons for
            this including resource shortage and special Flow export
            policies.
         </paragraph>
       </description>
       <units>flows</units>
     </field>

     <field name="notSentPacketTotalCount" dataType="unsigned64"
            dataTypeSemantics="totalCounter"
            group="processCounter"
            elementId="167" applicability="data" status="current">
       <description>
         <paragraph>
            The total number of packets in Flow Records that were
            generated by the Metering Process and dropped
            by the Metering Process or by the Exporting Process
            instead of being sent to the Collecting Process.
            There are several potential reasons for this including
            resource shortage and special Flow export policies.
         </paragraph>
       </description>
       <units>packets</units>
     </field>
     <field name="notSentOctetTotalCount" dataType="unsigned64"
            dataTypeSemantics="totalCounter"
            group="processCounter"
            elementId="168" applicability="data" status="current">
       <description>
         <paragraph>
            The total number of octets in packets in Flow Records
            that were generated by the Metering Process and
            dropped by the Metering Process or by the Exporting
            Process instead of being sent to the Collecting Process.
            There are several potential reasons for this including
            resource shortage and special Flow export policies.
         </paragraph>
       </description>
       <units>octets</units>
     </field>

     <field name="ipVersion" dataType="unsigned8"
            group="ipHeader"
            dataTypeSemantics="identifier"
            elementId="60" applicability="all" status="current">
       <description>
         <paragraph>
         The IP version field in the IP packet header.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 791 for the definition of the version field
         in the IPv4 packet header.
         See RFC 2460 for the definition of the version field
         in the IPv6 packet header.
         Additional information on defined version numbers
         can be found at
         http://www.iana.org/assignments/version-numbers.
         </paragraph>
       </reference>
     </field>

     <field name="sourceIPv4Address" dataType="ipv4Address"
            group="ipHeader"
            dataTypeSemantics="identifier"
            elementId="8" applicability="all" status="current">
       <description>
         <paragraph>
         The IPv4 source address in the IP packet header.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 791 for the definition of the IPv4 source
         address field.
         </paragraph>
       </reference>
     </field>

     <field name="sourceIPv6Address" dataType="ipv6Address"
            group="ipHeader"
            dataTypeSemantics="identifier"
            elementId="27" applicability="all" status="current">
       <description>
         <paragraph>
         The IPv6 source address in the IP packet header.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 2460 for the definition of the
         Source Address field in the IPv6 header.
         </paragraph>
       </reference>
     </field>

     <field name="sourceIPv4PrefixLength" dataType="unsigned8"
            group="ipHeader"
            elementId="9" applicability="option" status="current">
       <description>
         <paragraph>
         The number of contiguous bits that are relevant in the
         sourceIPv4Prefix Information Element.
         </paragraph>
       </description>
       <units>bits</units>
       <range>0-32</range>
     </field>

     <field name="sourceIPv6PrefixLength" dataType="unsigned8"
            group="ipHeader"
            elementId="29" applicability="option" status="current">
       <description>
         <paragraph>
         The number of contiguous bits that are relevant in the
         sourceIPv6Prefix Information Element.
         </paragraph>
       </description>
       <units>bits</units>
       <range>0-128</range>
     </field>

     <field name="sourceIPv4Prefix" dataType="ipv4Address"
            group="ipHeader"
            elementId="44" applicability="data" status="current">
       <description>
         <paragraph>
         IPv4 source address prefix.
         </paragraph>
       </description>
     </field>

     <field name="sourceIPv6Prefix" dataType="ipv6Address"
            group="ipHeader"
            elementId="170" applicability="data" status="current">
       <description>
         <paragraph>
         IPv6 source address prefix.
         </paragraph>
       </description>
     </field>

     <field name="destinationIPv4Address" dataType="ipv4Address"
            group="ipHeader"
            dataTypeSemantics="identifier"
            elementId="12" applicability="all" status="current">
       <description>
         <paragraph>
         The IPv4 destination address in the IP packet header.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 791 for the definition of the IPv4
         destination address field.
         </paragraph>
       </reference>
     </field>

     <field name="destinationIPv6Address" dataType="ipv6Address"
            group="ipHeader"
            dataTypeSemantics="identifier"
            elementId="28" applicability="all" status="current">
       <description>
         <paragraph>
         The IPv6 destination address in the IP packet header.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 2460 for the definition of the
         Destination Address field in the IPv6 header.
         </paragraph>
       </reference>
     </field>

     <field name="destinationIPv4PrefixLength" dataType="unsigned8"
            group="ipHeader"
            elementId="13" applicability="option" status="current">
       <description>
         <paragraph>
         The number of contiguous bits that are relevant in the
         destinationIPv4Prefix Information Element.
         </paragraph>
       </description>
       <units>bits</units>
       <range>0-32</range>
     </field>

     <field name="destinationIPv6PrefixLength" dataType="unsigned8"
            group="ipHeader"
            elementId="30" applicability="option" status="current">
       <description>
         <paragraph>
         The number of contiguous bits that are relevant in the
         destinationIPv6Prefix Information Element.
         </paragraph>
       </description>
       <units>bits</units>
       <range>0-128</range>
     </field>

     <field name="destinationIPv4Prefix" dataType="ipv4Address"
            group="ipHeader"
            elementId="45" applicability="data" status="current">
       <description>
         <paragraph> IPv4 destination address prefix. </paragraph>
       </description>
     </field>

     <field name="destinationIPv6Prefix" dataType="ipv6Address"
            group="ipHeader"
            elementId="169" applicability="data" status="current">
       <description>
         <paragraph> IPv6 destination address prefix. </paragraph>
       </description>
     </field>

     <field name="ipTTL" dataType="unsigned8"
            group="ipHeader"
            elementId="192" applicability="all" status="current">
       <description>
         <paragraph>
         For IPv4, the value of the Information Element matches
         the value of the Time to Live (TTL) field in the IPv4 packet
         header.  For IPv6, the value of the Information Element
         matches the value of the Hop Limit field in the IPv6
         packet header.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 791 for the definition of the IPv4
         Time to Live field.
         See RFC 2460 for the definition of the IPv6
         Hop Limit field.
         </paragraph>
       </reference>
       <units>hops</units>
     </field>

     <field name="protocolIdentifier" dataType="unsigned8"
            group="ipHeader"
            dataTypeSemantics="identifier"
            elementId="4" applicability="all" status="current">
       <description>
         <paragraph>
         The value of the protocol number in the IP packet header.
         The protocol number identifies the IP packet payload type.
         Protocol numbers are defined in the IANA Protocol Numbers
         registry.
            </paragraph>

         <paragraph>
         In Internet Protocol version 4 (IPv4), this is carried in the
         Protocol field.  In Internet Protocol version 6 (IPv6), this
         is carried in the Next Header field in the last extension
         header of the packet.
            </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 791 for the specification of the IPv4
         protocol field.
         See RFC 2460 for the specification of the IPv6
         protocol field.
         See the list of protocol numbers assigned by IANA at
         http://www.iana.org/assignments/protocol-numbers.
         </paragraph>
       </reference>
     </field>

     <field name="nextHeaderIPv6" dataType="unsigned8"
            group="ipHeader"
            elementId="193" applicability="all" status="current">
       <description>
         <paragraph>
         The value of the Next Header field of the IPv6 header.
         The value identifies the type of the following IPv6
         extension header or of the following IP payload.
         Valid values are defined in the IANA
         Protocol Numbers registry.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 2460 for the definition of the IPv6
         Next Header field.
         See the list of protocol numbers assigned by IANA at
         http://www.iana.org/assignments/protocol-numbers.
         </paragraph>
       </reference>
     </field>

     <field name="ipDiffServCodePoint" dataType="unsigned8"
            group="ipHeader"
            dataTypeSemantics="identifier"
            elementId="195" applicability="all" status="current">
       <description>
         <paragraph>
         The value of a Differentiated Services Code Point (DSCP)
         encoded in the Differentiated Services field.  The
         Differentiated Services field spans the most significant
         6 bits of the IPv4 TOS field or the IPv6 Traffic Class
         field, respectively.
         </paragraph>
         <paragraph>
         This Information Element encodes only the 6 bits of the
         Differentiated Services field.  Therefore, its value may
         range from 0 to 63.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 3260 for the definition of the
         Differentiated Services field.
         See RFC 1812 (Section 5.3.2) and RFC 791 for the definition
         of the IPv4 TOS field.  See RFC 2460 for the definition of
         the IPv6 Traffic Class field.
         </paragraph>
       </reference>
       <range>0-63</range>
     </field>

     <field name="ipPrecedence" dataType="unsigned8"
            group="ipHeader"
            dataTypeSemantics="identifier"
            elementId="196" applicability="all" status="current">
       <description>
         <paragraph>
         The value of the IP Precedence.  The IP Precedence value
         is encoded in the first 3 bits of the IPv4 TOS field
         or the IPv6 Traffic Class field, respectively.
         </paragraph>
         <paragraph>
         This Information Element encodes only these 3 bits.
         Therefore, its value may range from 0 to 7.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 1812 (Section 5.3.3) and RFC 791
         for the definition of the IP Precedence.
         See RFC 1812 (Section 5.3.2) and RFC 791
         for the definition of the IPv4 TOS field.
         See RFC 2460 for the definition of the IPv6
         Traffic Class field.
         </paragraph>
       </reference>
       <range>0-7</range>
     </field>

     <field name="ipClassOfService" dataType="unsigned8"
            group="ipHeader"
            dataTypeSemantics="identifier"
            elementId="5" applicability="all" status="current">
       <description>
         <paragraph>
         For IPv4 packets, this is the value of the TOS field in
         the IPv4 packet header.  For IPv6 packets, this is the
         value of the Traffic Class field in the IPv6 packet header.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 1812 (Section 5.3.2) and RFC 791
         for the definition of the IPv4 TOS field.
         See RFC 2460 for the definition of the IPv6
         Traffic Class field.
         </paragraph>
       </reference>
     </field>

     <field name="postIpClassOfService" dataType="unsigned8"
            group="ipHeader"
            dataTypeSemantics="identifier"
            elementId="55" applicability="all" status="current">
       <description>
         <paragraph>
         The definition of this Information Element is identical
         to the definition of Information Element
         'ipClassOfService', except that it reports a
         potentially modified value caused by a middlebox
         function after the packet passed the Observation Point.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 791 for the definition of the IPv4
         TOS field.
         See RFC 2460 for the definition of the IPv6
         Traffic Class field.
         See RFC 3234 for the definition of middleboxes.
         </paragraph>
       </reference>
     </field>

     <field name="flowLabelIPv6" dataType="unsigned32"
            group="ipHeader"
            dataTypeSemantics="identifier"
            elementId="31" applicability="all" status="current">
       <description>
         <paragraph>
         The value of the IPv6 Flow Label field in the IP packet header.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 2460 for the definition of the
         Flow Label field in the IPv6 packet header.
         </paragraph>
       </reference>
     </field>

     <field name="isMulticast" dataType="unsigned8"
            group="ipHeader"
            dataTypeSemantics="flags"
            elementId="206" applicability="data" status="current">
       <description>
         <paragraph>
           If the IP destination address is not a reserved multicast
           address, then the value of all bits of the octet (including
           the reserved ones) is zero.
         </paragraph>
         <paragraph>
           The first bit of this octet is set to 1 if the Version
           field of the IP header has the value 4 and if the
           Destination Address field contains a reserved multicast
           address in the range from 224.0.0.0 to 239.255.255.255.
           Otherwise, this bit is set to 0.
         </paragraph>
         <paragraph>
           The second and third bits of this octet are reserved for
           future use.
         </paragraph>
         <paragraph>
           The remaining bits of the octet are only set to values
           other than zero if the IP Destination Address is a
           reserved IPv6 multicast address.  Then the fourth bit
           of the octet is set to the value of the T flag in the
           IPv6 multicast address and the remaining four bits are
           set to the value of the scope field in the IPv6
           multicast address.
         </paragraph>
         <artwork>
             0      1      2      3      4      5      6      7
          +------+------+------+------+------+------+------+------+
          | MCv4 | RES. | RES. |  T   |   IPv6 multicast scope    |
          +------+------+------+------+------+------+------+------+

          Bit  0:    set to 1 if IPv4 multicast
          Bits 1-2:  reserved for future use
          Bit  4:    set to value of T flag, if IPv6 multicast
          Bits 4-7:  set to value of multicast scope if IPv6 multicast
         </artwork>
       </description>
       <reference>
         <paragraph>
         See RFC 1112 for the specification of reserved
         IPv4 multicast addresses.
         See RFC 4291 for the specification of reserved
         IPv6 multicast addresses and the definition of the T flag
         and the IPv6 multicast scope.
         </paragraph>
       </reference>
     </field>

     <field name="fragmentIdentification" dataType="unsigned32"
            group="ipHeader"
            dataTypeSemantics="identifier"
            elementId="54" applicability="data" status="current">
       <description>
         <paragraph>
         The value of the Identification field
         in the IPv4 packet header or the IPv6 Fragment header,
         respectively.  The value is 0 for IPv6 if there is
         no fragment header.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 791 for the definition of the IPv4
         Identification field.
         See RFC 2460 for the definition of the
         Identification field in the IPv6 Fragment header.
         </paragraph>
       </reference>
     </field>

     <field name="fragmentOffset" dataType="unsigned16"
            group="ipHeader"
            dataTypeSemantics="identifier"
            elementId="88" applicability="all" status="current">
       <description>
         <paragraph>
         The value of the IP fragment offset field in the
         IPv4 packet header or the IPv6 Fragment header,
         respectively.  The value is 0 for IPv6 if there is
         no fragment header.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 791 for the specification of the
         fragment offset in the IPv4 header.
         See RFC 2460 for the specification of the
         fragment offset in the IPv6 Fragment header.
         </paragraph>
       </reference>
     </field>

     <field name="fragmentFlags" dataType="unsigned8"
            group="ipHeader"
            dataTypeSemantics="flags"
            elementId="197" applicability="all" status="current">
       <description>
         <paragraph>
           Fragmentation properties indicated by flags in the IPv4
           packet header or the IPv6 Fragment header, respectively.
         </paragraph>
         <artwork>

         Bit 0:    (RS) Reserved.
                   The value of this bit MUST be 0 until specified
                   otherwise.
         Bit 1:    (DF) 0 = May Fragment,  1 = Don't Fragment.
                   Corresponds to the value of the DF flag in the
                   IPv4 header.  Will always be 0 for IPv6 unless
                   a "don't fragment" feature is introduced to IPv6.
         Bit 2:    (MF) 0 = Last Fragment, 1 = More Fragments.
                   Corresponds to the MF flag in the IPv4 header
                   or to the M flag in the IPv6 Fragment header,
                   respectively.  The value is 0 for IPv6 if there
                   is no fragment header.
         Bits 3-7: (DC) Don't Care.
                   The values of these bits are irrelevant.

             0   1   2   3   4   5   6   7
           +---+---+---+---+---+---+---+---+
           | R | D | M | D | D | D | D | D |
           | S | F | F | C | C | C | C | C |
           +---+---+---+---+---+---+---+---+
         </artwork>
       </description>
       <reference>
         <paragraph>
         See RFC 791 for the specification of the IPv4
         fragment flags.
         See RFC 2460 for the specification of the IPv6
         Fragment header.
         </paragraph>
       </reference>
     </field>

     <field name="ipHeaderLength" dataType="unsigned8"
            group="ipHeader"
            elementId="189" applicability="all" status="current">
       <description>
         <paragraph>
         The length of the IP header.  For IPv6, the value of this
         Information Element is 40.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 791 for the specification of the
         IPv4 header.
         See RFC 2460 for the specification of the
         IPv6 header.
         </paragraph>
       </reference>
       <units>octets</units>
     </field>

     <field name="ipv4IHL" dataType="unsigned8"
            group="ipHeader"
            elementId="207" applicability="all" status="current">
       <description>
         <paragraph>
         The value of the Internet Header Length (IHL) field in
         the IPv4 header.  It specifies the length of the header
         in units of 4 octets.  Please note that its unit is
         different from most of the other Information Elements
         reporting length values.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 791 for the specification of the
         IPv4 header.
         </paragraph>
       </reference>
       <units>4 octets</units>
     </field>

     <field name="totalLengthIPv4" dataType="unsigned16"
            group="ipHeader"
            elementId="190" applicability="all" status="current">
       <description>
         <paragraph>
         The total length of the IPv4 packet.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 791 for the specification of the
         IPv4 total length.
         </paragraph>
       </reference>
       <units>octets</units>
     </field>

     <field name="ipTotalLength" dataType="unsigned64"
            group="ipHeader"
            elementId="224" applicability="all" status="current">
       <description>
         <paragraph>
         The total length of the IP packet.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 791 for the specification of the
         IPv4 total length.
         See RFC 2460 for the specification of the
         IPv6 payload length.
         See RFC 2675 for the specification of the
         IPv6 jumbo payload length.
         </paragraph>
       </reference>
       <units>octets</units>
     </field>

     <field name="payloadLengthIPv6" dataType="unsigned16"
            group="ipHeader"
            elementId="191" applicability="all" status="current">
       <description>
         <paragraph>
         This Information Element reports the value of the Payload
         Length field in the IPv6 header.  Note that IPv6 extension
         headers belong to the payload.  Also note that in case of a
         jumbo payload option the value of the Payload Length field in
         the IPv6 header is zero and so will be the value reported
         by this Information Element.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 2460 for the specification of the
         IPv6 payload length.
         See RFC 2675 for the specification of the
         IPv6 jumbo payload option.
         </paragraph>
       </reference>
     </field>

     <field name="sourceTransportPort" dataType="unsigned16"
            group="transportHeader"
            dataTypeSemantics="identifier"
            elementId="7" applicability="all" status="current">
       <description>
         <paragraph>
         The source port identifier in the transport header.
         For the transport protocols UDP, TCP, and SCTP, this is the
         source port number given in the respective header.  This
         field MAY also be used for future transport protocols that
         have 16-bit source port identifiers.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 768 for the definition of the UDP
         source port field.
         See RFC 793 for the definition of the TCP
         source port field.
         See RFC 4960 for the definition of SCTP.
         </paragraph>
         <paragraph>
         Additional information on defined UDP and TCP port numbers can
         be found at http://www.iana.org/assignments/port-numbers.
         </paragraph>
       </reference>
     </field>

     <field name="destinationTransportPort" dataType="unsigned16"
            group="transportHeader"
            dataTypeSemantics="identifier"
            elementId="11" applicability="all" status="current">
       <description>
         <paragraph>
         The destination port identifier in the transport header.
         For the transport protocols UDP, TCP, and SCTP, this is the
         destination port number given in the respective header.
         This field MAY also be used for future transport protocols
         that have 16-bit destination port identifiers.

         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 768 for the definition of the UDP
         destination port field.
         See RFC 793 for the definition of the TCP
         destination port field.
         See RFC 4960 for the definition of SCTP.
         </paragraph>
         <paragraph>
         Additional information on defined UDP and TCP port numbers can
         be found at http://www.iana.org/assignments/port-numbers.
         </paragraph>
       </reference>
     </field>

     <field name="udpSourcePort" dataType="unsigned16"
            group="transportHeader"
            dataTypeSemantics="identifier"
            elementId="180" applicability="all" status="current">
       <description>
         <paragraph>
         The source port identifier in the UDP header.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 768 for the definition of the
         UDP source port field.
         Additional information on defined UDP port numbers can
         be found at http://www.iana.org/assignments/port-numbers.
         </paragraph>
       </reference>
     </field>

     <field name="udpDestinationPort" dataType="unsigned16"
            group="transportHeader"
            dataTypeSemantics="identifier"
            elementId="181" applicability="all" status="current">
       <description>
         <paragraph>
         The destination port identifier in the UDP header.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 768 for the definition of the
         UDP destination port field.
         Additional information on defined UDP port numbers can
         be found at http://www.iana.org/assignments/port-numbers.
         </paragraph>
       </reference>
     </field>

     <field name="udpMessageLength" dataType="unsigned16"
            group="transportHeader"
            elementId="205" applicability="all" status="current">
       <description>
         <paragraph>
         The value of the Length field in the UDP header.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 768 for the specification of the
         UDP header.
         </paragraph>
       </reference>
       <units>octets</units>
     </field>

     <field name="tcpSourcePort" dataType="unsigned16"
            group="transportHeader"
            dataTypeSemantics="identifier"
            elementId="182" applicability="all" status="current">
       <description>
         <paragraph>
         The source port identifier in the TCP header.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 793 for the definition of the TCP
         source port field.
         Additional information on defined TCP port numbers can
         be found at http://www.iana.org/assignments/port-numbers.
         </paragraph>
       </reference>
     </field>

     <field name="tcpDestinationPort" dataType="unsigned16"
            group="transportHeader"
            dataTypeSemantics="identifier"
            elementId="183" applicability="all" status="current">
       <description>
         <paragraph>
         The destination port identifier in the TCP header.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 793 for the definition of the TCP
         source port field.
         Additional information on defined TCP port numbers can
         be found at http://www.iana.org/assignments/port-numbers.
         </paragraph>
       </reference>
     </field>

     <field name="tcpSequenceNumber" dataType="unsigned32"
            group="transportHeader"
            elementId="184" applicability="all" status="current">
       <description>
         <paragraph>
         The sequence number in the TCP header.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 793 for the definition of the TCP
         sequence number.
         </paragraph>
       </reference>
     </field>

     <field name="tcpAcknowledgementNumber" dataType="unsigned32"
            group="transportHeader"
            elementId="185" applicability="all" status="current">
       <description>
         <paragraph>
         The acknowledgement number in the TCP header.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 793 for the definition of the TCP
         acknowledgement number.
         </paragraph>
       </reference>
     </field>

     <field name="tcpWindowSize" dataType="unsigned16"
            group="transportHeader"
            elementId="186" applicability="all" status="current">
       <description>
         <paragraph>
         The window field in the TCP header.
         If the TCP window scale is supported,
         then TCP window scale must be known
         to fully interpret the value of this information.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 793 for the definition of the TCP window field.
         See RFC 1323 for the definition of the TCP window scale.
         </paragraph>
       </reference>
     </field>

     <field name="tcpWindowScale" dataType="unsigned16"
            group="transportHeader"
            elementId="238" applicability="all" status="current">
       <description>
         <paragraph>
         The scale of the window field in the TCP header.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 1323 for the definition of the TCP window scale.
         </paragraph>
       </reference>
     </field>

     <field name="tcpUrgentPointer" dataType="unsigned16"
            group="transportHeader"
            elementId="187" applicability="all" status="current">
       <description>
         <paragraph>
         The urgent pointer in the TCP header.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 793 for the definition of the TCP
         urgent pointer.
         </paragraph>
       </reference>
     </field>
     <field name="tcpHeaderLength" dataType="unsigned8"
            group="transportHeader"
            elementId="188" applicability="all" status="current">
       <description>
         <paragraph>
         The length of the TCP header.  Note that the value of this
         Information Element is different from the value of the Data
         Offset field in the TCP header.  The Data Offset field
         indicates the length of the TCP header in units of 4 octets.
         This Information Elements specifies the length of the TCP
         header in units of octets.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 793 for the definition of the
         TCP header.
         </paragraph>
       </reference>
       <units>octets</units>
     </field>

     <field name="icmpTypeCodeIPv4" dataType="unsigned16"
            group="transportHeader"
            dataTypeSemantics="identifier"
            elementId="32" applicability="all" status="current">
       <description>
         <paragraph>
         Type and Code of the IPv4 ICMP message.  The combination of
         both values is reported as (ICMP type * 256) + ICMP code.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 792 for the definition of the IPv4 ICMP
            type and code fields.
         </paragraph>
       </reference>
     </field>

     <field name="icmpTypeIPv4" dataType="unsigned8"
            group="transportHeader"
            dataTypeSemantics="identifier"
            elementId="176" applicability="all" status="current">
       <description>
         <paragraph>
         Type of the IPv4 ICMP message.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 792 for the definition of the IPv4 ICMP
         type field.
         </paragraph>
       </reference>
     </field>

     <field name="icmpCodeIPv4" dataType="unsigned8"
            group="transportHeader"
            dataTypeSemantics="identifier"
            elementId="177" applicability="all" status="current">
       <description>
         <paragraph>
         Code of the IPv4 ICMP message.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 792 for the definition of the IPv4
         ICMP code field.
         </paragraph>
       </reference>
     </field>

     <field name="icmpTypeCodeIPv6" dataType="unsigned16"
            group="transportHeader"
            dataTypeSemantics="identifier"
            elementId="139" applicability="all" status="current">
       <description>
         <paragraph>
         Type and Code of the IPv6 ICMP message.  The combination of
         both values is reported as (ICMP type * 256) + ICMP code.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 4443 for the definition of the IPv6
         ICMP type and code fields.
         </paragraph>
       </reference>
     </field>

     <field name="icmpTypeIPv6" dataType="unsigned8"
            group="transportHeader"
            dataTypeSemantics="identifier"
            elementId="178" applicability="all" status="current">
       <description>
         <paragraph>
         Type of the IPv6 ICMP message.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 4443 for the definition of the IPv6
         ICMP type field.
         </paragraph>
       </reference>
     </field>

     <field name="icmpCodeIPv6" dataType="unsigned8"
            group="transportHeader"
            dataTypeSemantics="identifier"
            elementId="179" applicability="all" status="current">
       <description>
         <paragraph>
         Code of the IPv6 ICMP message.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 4443 for the definition of the IPv6
         ICMP code field.
         </paragraph>
       </reference>
     </field>

     <field name="igmpType" dataType="unsigned8"
            group="transportHeader"
            dataTypeSemantics="identifier"
            elementId="33" applicability="all" status="current">
       <description>
         <paragraph>
         The type field of the IGMP message.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 3376 for the definition of the IGMP
         type field.
         </paragraph>
       </reference>
     </field>

     <field name="sourceMacAddress" dataType="macAddress"
            group="subIpHeader"
            dataTypeSemantics="identifier"
            elementId="56" applicability="data" status="current">
       <description>
         <paragraph>
           The IEEE 802 source MAC address field.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See IEEE.802-3.2002.
         </paragraph>
       </reference>
     </field>

     <field name="postSourceMacAddress" dataType="macAddress"
            group="subIpHeader"
            dataTypeSemantics="identifier"
            elementId="81" applicability="data" status="current">
       <description>
         <paragraph>
         The definition of this Information Element is identical
         to the definition of Information Element
         'sourceMacAddress', except that it reports a
         potentially modified value caused by a middlebox
         function after the packet passed the Observation Point.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See IEEE.802-3.2002.
         </paragraph>
       </reference>
     </field>

     <field name="vlanId" dataType="unsigned16"
            group="subIpHeader"
            dataTypeSemantics="identifier"
            elementId="58" applicability="data" status="current">
       <description>
         <paragraph>
           The IEEE 802.1Q VLAN identifier (VID) extracted from the Tag
           Control Information field that was attached to the IP packet.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See IEEE.802-1Q.2003.

         </paragraph>
       </reference>
     </field>

     <field name="postVlanId" dataType="unsigned16"
            group="subIpHeader"
            dataTypeSemantics="identifier"
            elementId="59" applicability="data" status="current">
       <description>
         <paragraph>
         The definition of this Information Element is identical
         to the definition of Information Element
         'vlanId', except that it reports a
         potentially modified value caused by a middlebox
         function after the packet passed the Observation Point.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See IEEE.802-1Q.2003.
         </paragraph>
       </reference>
     </field>

     <field name="destinationMacAddress" dataType="macAddress"
            group="subIpHeader"
            dataTypeSemantics="identifier"
            elementId="80" applicability="data" status="current">
       <description>
         <paragraph>
           The IEEE 802 destination MAC address field.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See IEEE.802-3.2002.
         </paragraph>
       </reference>
     </field>

     <field name="postDestinationMacAddress" dataType="macAddress"
            group="subIpHeader"
            dataTypeSemantics="identifier"
            elementId="57" applicability="data" status="current">
       <description>
         <paragraph>
         The definition of this Information Element is identical
         to the definition of Information Element
         'destinationMacAddress', except that it reports a
         potentially modified value caused by a middlebox
         function after the packet passed the Observation Point.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See IEEE.802-3.2002.
         </paragraph>
       </reference>
     </field>

     <field name="wlanChannelId" dataType="unsigned8"
            group="subIpHeader"
            dataTypeSemantics="identifier"
            elementId="146" applicability="data" status="current">
       <description>
         <paragraph>
           The identifier of the 802.11 (Wi-Fi) channel used.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See IEEE.802-11.1999.
         </paragraph>
       </reference>
     </field>

     <field name="wlanSSID" dataType="string"
            group="subIpHeader"
            elementId="147" applicability="data" status="current">
       <description>
         <paragraph>
           The Service Set IDentifier (SSID) identifying an 802.11
           (Wi-Fi) network used.  According to IEEE.802-11.1999, the
           SSID is encoded into a string of up to 32 characters.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See IEEE.802-11.1999.
         </paragraph>
       </reference>
     </field>

     <field name="mplsTopLabelTTL" dataType="unsigned8"
            group="subIpHeader"
            elementId="200" applicability="all" status="current">
       <description>
         <paragraph>
         The TTL field from the top MPLS label stack entry,
         i.e., the last label that was pushed.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 3032 for the specification of the
         TTL field.
         </paragraph>
       </reference>
     </field>

     <field name="mplsTopLabelExp" dataType="unsigned8"
            group="subIpHeader"
            dataTypeSemantics="flags"
            elementId="203" applicability="all" status="current">
       <description>
         <paragraph>
         The Exp field from the top MPLS label stack entry,
         i.e., the last label that was pushed.
         </paragraph>
         <artwork>
         Bits 0-4:  Don't Care, value is irrelevant.
         Bits 5-7:  MPLS Exp field.

             0   1   2   3   4   5   6   7
           +---+---+---+---+---+---+---+---+
           |     don't care    |    Exp    |
           +---+---+---+---+---+---+---+---+
         </artwork>
       </description>
       <reference>
         <paragraph>
         See RFC 3032 for the specification of the Exp field.
         See RFC 3270 for usage of the Exp field.
         </paragraph>
       </reference>
     </field>

     <field name="postMplsTopLabelExp" dataType="unsigned8"
            group="subIpHeader"
            dataTypeSemantics="flags"
            elementId="237" applicability="all" status="current">
       <description>
         <paragraph>
         The definition of this Information Element is identical to the
         definition of Information Element 'mplsTopLabelExp', except
         that it reports a potentially modified value caused by a
         middlebox function after the packet passed the Observation
         Point.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 3032 for the specification of the Exp field.
         See RFC 3270 for usage of the Exp field.
         </paragraph>
       </reference>
     </field>

     <field name="mplsLabelStackDepth" dataType="unsigned32"
            group="subIpHeader"
            elementId="202" applicability="all" status="current">
       <description>
         <paragraph>
         The number of labels in the MPLS label stack.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 3032 for the specification of
         the MPLS label stack.
         </paragraph>
       </reference>
       <units>label stack entries</units>
     </field>

     <field name="mplsLabelStackLength" dataType="unsigned32"
            group="subIpHeader"
            elementId="201" applicability="all" status="current">
       <description>
         <paragraph>
         The length of the MPLS label stack in units of octets.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 3032 for the specification of
         the MPLS label stack.
         </paragraph>
       </reference>
       <units>octets</units>
     </field>
     <field name="mplsPayloadLength" dataType="unsigned32"
            group="subIpHeader"
            elementId="194" applicability="all" status="current">
       <description>
         <paragraph>
         The size of the MPLS packet without the label stack.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 3031 for the specification of
         MPLS packets.
         See RFC 3032 for the specification of
         the MPLS label stack.
         </paragraph>
       </reference>
       <units>octets</units>
     </field>

     <field name="mplsTopLabelStackSection" dataType="octetArray"
            group="subIpHeader"
            dataTypeSemantics="identifier"
            elementId="70" applicability="all" status="current">
       <description>
         <paragraph>
         The Label, Exp, and S fields from the top MPLS label
         stack entry, i.e., from the last label that was pushed.
         </paragraph>
         <paragraph>
         The size of this Information Element is 3 octets.
         </paragraph>
         <artwork>
       0                   1                   2
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                Label                  | Exp |S|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      Label:  Label Value, 20 bits
      Exp:    Experimental Use, 3 bits
      S:      Bottom of Stack, 1 bit
         </artwork>
       </description>
       <reference>
         <paragraph>
         See RFC 3032.
         </paragraph>
       </reference>
     </field>

     <field name="mplsLabelStackSection2" dataType="octetArray"
            group="subIpHeader"
            dataTypeSemantics="identifier"
            elementId="71" applicability="all" status="current">
       <description>
         <paragraph>
         The Label, Exp, and S fields from the label stack entry that
         was pushed immediately before the label stack entry that would
         be reported by mplsTopLabelStackSection.  See the definition of
         mplsTopLabelStackSection for further details.
         </paragraph>
         <paragraph>
         The size of this Information Element is 3 octets.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 3032.
         </paragraph>
       </reference>
     </field>

     <field name="mplsLabelStackSection3" dataType="octetArray"
            group="subIpHeader"
            dataTypeSemantics="identifier"
            elementId="72" applicability="all" status="current">
       <description>
         <paragraph>
         The Label, Exp, and S fields from the label stack entry that
         was pushed immediately before the label stack entry that would
         be reported by mplsLabelStackSection2.  See the definition of
         mplsTopLabelStackSection for further details.
         </paragraph>
         <paragraph>
         The size of this Information Element is 3 octets.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 3032.
         </paragraph>
       </reference>
     </field>

     <field name="mplsLabelStackSection4" dataType="octetArray"
            group="subIpHeader"
            dataTypeSemantics="identifier"
            elementId="73" applicability="all" status="current">
       <description>
         <paragraph>
         The Label, Exp, and S fields from the label stack entry that
         was pushed immediately before the label stack entry that would
         be reported by mplsLabelStackSection3.  See the definition of
         mplsTopLabelStackSection for further details.
         </paragraph>
         <paragraph>
         The size of this Information Element is 3 octets.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 3032.
         </paragraph>
       </reference>
     </field>

     <field name="mplsLabelStackSection5" dataType="octetArray"
            group="subIpHeader"
            dataTypeSemantics="identifier"
            elementId="74" applicability="all" status="current">
       <description>
         <paragraph>
         The Label, Exp, and S fields from the label stack entry that
         was pushed immediately before the label stack entry that would
         be reported by mplsLabelStackSection4.  See the definition of
         mplsTopLabelStackSection for further details.
         </paragraph>
         <paragraph>
         The size of this Information Element is 3 octets.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 3032.
         </paragraph>
       </reference>
     </field>

     <field name="mplsLabelStackSection6" dataType="octetArray"
            group="subIpHeader"
            dataTypeSemantics="identifier"
            elementId="75" applicability="all" status="current">
       <description>
         <paragraph>
         The Label, Exp, and S fields from the label stack entry that
         was pushed immediately before the label stack entry that would
         be reported by mplsLabelStackSection5.  See the definition of
         mplsTopLabelStackSection for further details.
         </paragraph>
         <paragraph>
         The size of this Information Element is 3 octets.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 3032.
         </paragraph>
       </reference>
     </field>

     <field name="mplsLabelStackSection7" dataType="octetArray"
            group="subIpHeader"
            dataTypeSemantics="identifier"
            elementId="76" applicability="all" status="current">
       <description>
         <paragraph>
         The Label, Exp, and S fields from the label stack entry that
         was pushed immediately before the label stack entry that would
         be reported by mplsLabelStackSection6.  See the definition of
         mplsTopLabelStackSection for further details.
         </paragraph>
         <paragraph>
         The size of this Information Element is 3 octets.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 3032.
         </paragraph>
       </reference>
     </field>

     <field name="mplsLabelStackSection8" dataType="octetArray"
            group="subIpHeader"
            dataTypeSemantics="identifier"
            elementId="77" applicability="all" status="current">
       <description>
         <paragraph>
         The Label, Exp, and S fields from the label stack entry that
         was pushed immediately before the label stack entry that would
         be reported by mplsLabelStackSection7.  See the definition of
         mplsTopLabelStackSection for further details.

         </paragraph>
         <paragraph>
         The size of this Information Element is 3 octets.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 3032.
         </paragraph>
       </reference>
     </field>

     <field name="mplsLabelStackSection9" dataType="octetArray"
            group="subIpHeader"
            dataTypeSemantics="identifier"
            elementId="78" applicability="all" status="current">
       <description>
         <paragraph>
         The Label, Exp, and S fields from the label stack entry that
         was pushed immediately before the label stack entry that would
         be reported by mplsLabelStackSection8.  See the definition of
         mplsTopLabelStackSection for further details.
         </paragraph>
         <paragraph>
         The size of this Information Element is 3 octets.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 3032.
         </paragraph>
       </reference>
     </field>

     <field name="mplsLabelStackSection10" dataType="octetArray"
            group="subIpHeader"
            dataTypeSemantics="identifier"
            elementId="79" applicability="all" status="current">
       <description>
         <paragraph>
         The Label, Exp, and S fields from the label stack entry that
         was pushed immediately before the label stack entry that would
         be reported by mplsLabelStackSection9.  See the definition of
         mplsTopLabelStackSection for further details.
         </paragraph>
         <paragraph>
         The size of this Information Element is 3 octets.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 3032.
         </paragraph>
       </reference>
     </field>

     <field name="ipPayloadLength" dataType="unsigned32"
            group="derived"
            elementId="204" applicability="all" status="current">
       <description>
         <paragraph>
         The effective length of the IP payload.
         </paragraph>
         <paragraph>
         For IPv4 packets, the value of this Information Element is
         the difference between the total length of the IPv4 packet
         (as reported by Information Element totalLengthIPv4) and the
         length of the IPv4 header (as reported by Information Element
         headerLengthIPv4).
         </paragraph>
         <paragraph>
         For IPv6, the value of the Payload Length field
         in the IPv6 header is reported except in the case that
         the value of this field is zero and that there is a valid
         jumbo payload option.  In this case, the value of the
         Jumbo Payload Length field in the jumbo payload option
         is reported.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 791 for the specification of
         IPv4 packets.
         See RFC 2460 for the specification of the
         IPv6 payload length.
         See RFC 2675 for the specification of the
         IPv6 jumbo payload length.
         </paragraph>
       </reference>
     </field>

     <field name="ipNextHopIPv4Address" dataType="ipv4Address"
            group="derived"
            dataTypeSemantics="identifier"
            elementId="15" applicability="data" status="current">
       <description>
         <paragraph>
         The IPv4 address of the next IPv4 hop.
         </paragraph>
       </description>
     </field>

     <field name="ipNextHopIPv6Address" dataType="ipv6Address"
            group="derived"
            dataTypeSemantics="identifier"
            elementId="62" applicability="data" status="current">
       <description>
         <paragraph>
         The IPv6 address of the next IPv6 hop.
         </paragraph>
       </description>
     </field>

     <field name="bgpSourceAsNumber" dataType="unsigned32"
            group="derived"
            dataTypeSemantics="identifier"
            elementId="16" applicability="all" status="current">
       <description>
         <paragraph>
         The autonomous system (AS) number of the source IP address.
         If AS path information for this Flow is only available as
         an unordered AS set (and not as an ordered AS sequence),
         then the value of this Information Element is 0.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 4271 for a description of BGP-4, and see RFC 1930
         for the definition of the AS number.
         </paragraph>
       </reference>
     </field>

     <field name="bgpDestinationAsNumber" dataType="unsigned32"
            group="derived"
            dataTypeSemantics="identifier"
            elementId="17" applicability="all" status="current">
       <description>
         <paragraph>
         The autonomous system (AS) number of the destination IP
         address.  If AS path information for this Flow is only
         available as an unordered AS set (and not as an ordered AS
         sequence), then the value of this Information Element is 0.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 4271 for a description of BGP-4, and see RFC 1930 for
            the definition of the AS number.
         </paragraph>
       </reference>
     </field>

     <field name="bgpNextAdjacentAsNumber" dataType="unsigned32"
            group="derived"
            dataTypeSemantics="identifier"
            elementId="128" applicability="all" status="current">
       <description>
         <paragraph>
         The autonomous system (AS) number of the first AS in the AS
         path to the destination IP address.  The path is deduced
         by looking up the destination IP address of the Flow in the
         BGP routing information base.  If AS path information for
         this Flow is only available as an unordered AS set (and not
         as an ordered AS sequence), then the value of this Information
         Element is 0.
       </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 4271 for a description of BGP-4, and
         see RFC 1930 for the definition of the AS number.
         </paragraph>
       </reference>
     </field>

     <field name="bgpPrevAdjacentAsNumber" dataType="unsigned32"
            group="derived"
            dataTypeSemantics="identifier"
            elementId="129" applicability="all" status="current">
       <description>
         <paragraph>
         The autonomous system (AS) number of the last AS in the AS
         path from the source IP address.  The path is deduced
         by looking up the source IP address of the Flow in the BGP
         routing information base.  If AS path information for this
         Flow is only available as an unordered AS set (and not as
         an ordered AS sequence), then the value of this Information
         Element is 0.  In case of BGP asymmetry, the
         bgpPrevAdjacentAsNumber might not be able to report the correct
         value.
       </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 4271 for a description of BGP-4, and
         see RFC 1930 for the definition of the AS number.
         </paragraph>
       </reference>
     </field>

     <field name="bgpNextHopIPv4Address" dataType="ipv4Address"
            group="derived"
            dataTypeSemantics="identifier"
            elementId="18" applicability="all" status="current">
       <description>
         <paragraph>
         The IPv4 address of the next (adjacent) BGP hop.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 4271 for a description of BGP-4.
         </paragraph>
       </reference>
     </field>

     <field name="bgpNextHopIPv6Address" dataType="ipv6Address"
            group="derived"
            dataTypeSemantics="identifier"
            elementId="63" applicability="all" status="current">
       <description>
         <paragraph>
         The IPv6 address of the next (adjacent) BGP hop.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 4271 for a description of BGP-4.
         </paragraph>
       </reference>
     </field>

     <field name="mplsTopLabelType" dataType="unsigned8"
            group="derived"
            dataTypeSemantics="identifier"
            elementId="46" applicability="data" status="current">
       <description>
         <paragraph>
         This field identifies the control protocol that allocated the
         top-of-stack label.  Initial values for this field are
         listed below.  Further values may be assigned by IANA in
         the MPLS label type registry.
         </paragraph>
         <artwork>
        - 0x01 TE-MIDPT: Any TE tunnel mid-point or tail label
        - 0x02 Pseudowire: Any PWE3 or Cisco AToM based label
        - 0x03 VPN: Any label associated with VPN
        - 0x04 BGP: Any label associated with BGP or BGP routing
        - 0x05 LDP: Any label associated with dynamically assigned
                    labels using LDP
         </artwork>
       </description>
       <reference>
         <paragraph>
         See RFC 3031 for the MPLS label structure.
         See RFC 4364 for the association of MPLS labels
         with Virtual Private Networks (VPNs).
         See RFC 4271 for BGP and BGP routing.
         See RFC 5036 for Label Distribution Protocol (LDP).
         See the list of MPLS label types assigned by IANA at
         http://www.iana.org/assignments/mpls-label-values.
         </paragraph>
       </reference>
     </field>

     <field name="mplsTopLabelIPv4Address" dataType="ipv4Address"
            group="derived"
            dataTypeSemantics="identifier"
            elementId="47" applicability="data" status="current">
       <description>
         <paragraph>
           The IPv4 address of the system that the MPLS top label will
           cause this Flow to be forwarded to.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 3031 for the association between
         MPLS labels and IP addresses.
         </paragraph>
       </reference>
     </field>

     <field name="mplsTopLabelIPv6Address" dataType="ipv6Address"
            group="derived"
            dataTypeSemantics="identifier"
            elementId="140" applicability="data" status="current">
       <description>
         <paragraph>
           The IPv6 address of the system that the MPLS top label will
           cause this Flow to be forwarded to.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 3031 for the association between
         MPLS labels and IP addresses.
         </paragraph>
       </reference>
     </field>

     <field name="mplsVpnRouteDistinguisher" dataType="octetArray"
            group="derived"
            dataTypeSemantics="identifier"
            elementId="90" applicability="all" status="current">
       <description>
         <paragraph>
         The value of the VPN route distinguisher of a corresponding
         entry in a VPN routing and forwarding table.  Route
         distinguisher ensures that the same address can be used in
         several different MPLS VPNs and that it is possible for BGP to
         carry several completely different routes to that address, one
         for each VPN.  According to RFC 4364, the size of
         mplsVpnRouteDistinguisher is 8 octets.  However, in RFC 4382 an
         octet string with flexible length was chosen for representing a
         VPN route distinguisher by object MplsL3VpnRouteDistinguisher.
         This choice was made in order to be open to future changes of
         the size.  This idea was adopted when choosing octetArray as
         abstract data type for this Information Element.  The maximum
         length of this Information Element is 256 octets.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 4364 for the specification of the route
         distinguisher.  See RFC 4382 for the specification
         of the MPLS/BGP Layer 3 Virtual Private Network (VPN)
         Management Information Base.
         </paragraph>
       </reference>
     </field>

     <field name="minimumIpTotalLength" dataType="unsigned64"
            group="minMax"
            elementId="25" applicability="all" status="current">
       <description>
         <paragraph>
         Length of the smallest packet observed for this Flow.
         The packet length includes the IP header(s) length and
         the IP payload length.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 791 for the specification of the
         IPv4 total length.
         See RFC 2460 for the specification of the
         IPv6 payload length.
         See RFC 2675 for the specification of the
         IPv6 jumbo payload length.
         </paragraph>
       </reference>
       <units>octets</units>
     </field>

     <field name="maximumIpTotalLength" dataType="unsigned64"
            group="minMax"
            elementId="26" applicability="all" status="current">
       <description>
         <paragraph>
         Length of the largest packet observed for this Flow.
         The packet length includes the IP header(s) length and
         the IP payload length.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 791 for the specification of the
         IPv4 total length.
         See RFC 2460 for the specification of the
         IPv6 payload length.
         See RFC 2675 for the specification of the
         IPv6 jumbo payload length.
         </paragraph>
       </reference>
       <units>octets</units>
     </field>

     <field name="minimumTTL" dataType="unsigned8"
            group="minMax"
            elementId="52" applicability="data" status="current">
       <description>
         <paragraph>
           Minimum TTL value observed for any packet in this Flow.
         </paragraph>
       </description>
     </field>

     <field name="maximumTTL" dataType="unsigned8"
            group="minMax"
            elementId="53" applicability="data" status="current">
       <description>
         <paragraph>
           Maximum TTL value observed for any packet in this Flow.
         </paragraph>
       </description>
     </field>

     <field name="ipv4Options" dataType="unsigned32"
            dataTypeSemantics="flags"
            group="minMax"
            elementId="208" applicability="all" status="current">
       <description>
         <paragraph>
         IPv4 options in packets of this Flow.
         The information is encoded in a set of bit fields.  For
         each valid IPv4 option type, there is a bit in this set.
         The bit is set to 1 if any observed packet of this Flow
         contains the corresponding IPv4 option type.  Otherwise,
         if no observed packet of this Flow contained the
         respective IPv4 option type, the value of the
         corresponding bit is 0.
         </paragraph>
         <paragraph>
         The list of valid IPv4 options is maintained by IANA.
         Note that for identifying an option not just the 5-bit
         Option Number, but all 8 bits of the Option Type need to
         match one of the IPv4 options specified at
         http://www.iana.org/assignments/ip-parameters.
         </paragraph>
         <paragraph>
         Options are mapped to bits according to their option numbers.
         Option number X is mapped to bit X.
         The mapping is illustrated by the figure below.
         </paragraph>
         <artwork>
           0      1      2      3      4      5      6      7
       +------+------+------+------+------+------+------+------+
       | EOOL | NOP  | SEC  | LSR  |  TS  |E-SEC |CIPSO |  RR  | ...
       +------+------+------+------+------+------+------+------+

           8      9     10     11     12     13     14     15
       +------+------+------+------+------+------+------+------+
   ... | SID  | SSR  | ZSU  | MTUP | MTUR | FINN | VISA |ENCODE| ...
       +------+------+------+------+------+------+------+------+

          16     17     18     19     20     21     22     23
       +------+------+------+------+------+------+------+------+
   ... |IMITD | EIP  |  TR  |ADDEXT|RTRALT| SDB  |NSAPA | DPS  | ...
       +------+------+------+------+------+------+------+------+

          24     25     26     27     28     29     30     31
       +------+------+------+------+------+------+------+------+
   ... | UMP  |             to be assigned by IANA             |
       +------+------+------+------+------+------+------+------+

           Type   Option
       Bit Value  Name    Reference
       ---+-----+-------+------------------------------------
        0     0   EOOL    End of Options List, RFC 791
        1     1   NOP     No Operation, RFC 791
        2   130   SEC     Security, RFC 1108
        3   131   LSR     Loose Source Route, RFC 791
        4    68   TS      Timestamp,      Time Stamp, RFC 791
        5   133   E-SEC   Extended Security, RFC 1108
        6   134   CIPSO   Commercial Security
        7     7   RR      Record Route, RFC 791
        8   136   SID     Stream ID, RFC 791
        9   137   SSR     Strict Source Route, RFC 791
       10    10   ZSU     Experimental Measurement
       11    11   MTUP    (obsoleted) MTU Probe, RFC 1191
       12    12   MTUR    (obsoleted) MTU Reply, RFC 1191
       13   205   FINN    Experimental Flow Control
       14   142   VISA    Experimental Access Control
       15    15   ENCODE
       16   144   IMITD   IMI Traffic Descriptor
       17   145   EIP     Extended Internet Protocol, RFC 1385
       18    82   TR      Traceroute, RFC 3193
       19   147   ADDEXT  Address Extension
       20   148   RTRALT  Router Alert, RFC 2113
       21   149   SDB     Selective Directed Broadcast
       22   150   NSAPA   NSAP Address
       23   151   DPS     Dynamic Packet State
       24   152   UMP     Upstream Multicast Pkt.

       ...  ...   ...     Further options numbers
                          may be assigned by IANA

         </artwork>
       </description>
       <reference>
         <paragraph>
         See RFC 791 for the definition of IPv4 options.
         See the list of IPv4 option numbers assigned by IANA
         at http://www.iana.org/assignments/ip-parameters.
         </paragraph>
       </reference>
     </field>

     <field name="ipv6ExtensionHeaders" dataType="unsigned32"
            dataTypeSemantics="flags"
            group="minMax"
            elementId="64" applicability="all" status="current">
       <description>
         <paragraph>
         IPv6 extension headers observed in packets of this Flow.
         The information is encoded in a set of bit fields.  For
         each IPv6 option header, there is a bit in this set.
         The bit is set to 1 if any observed packet of this Flow
         contains the corresponding IPv6 extension header.
         Otherwise, if no observed packet of this Flow contained
         the respective IPv6 extension header, the value of the
         corresponding bit is 0.
         </paragraph>
         <artwork>
              0     1     2     3     4     5     6     7
          +-----+-----+-----+-----+-----+-----+-----+-----+
          | Res | FRA1| RH  | FRA0| UNK | Res | HOP | DST |  ...
          +-----+-----+-----+-----+-----+-----+-----+-----+

              8     9    10    11    12    13    14    15
          +-----+-----+-----+-----+-----+-----+-----+-----+
      ... | PAY | AH  | ESP |         Reserved            | ...
          +-----+-----+-----+-----+-----+-----+-----+-----+

             16    17    18    19    20    21    22    23
          +-----+-----+-----+-----+-----+-----+-----+-----+
      ... |                  Reserved                     | ...
          +-----+-----+-----+-----+-----+-----+-----+-----+
             24    25    26    27    28    29    30    31
          +-----+-----+-----+-----+-----+-----+-----+-----+
      ... |                  Reserved                     |
          +-----+-----+-----+-----+-----+-----+-----+-----+

        Bit    IPv6 Option   Description
       0, Res               Reserved
       1, FRA1     44       Fragmentation header - not first fragment
       2, RH       43       Routing header
       3, FRA0     44       Fragment header - first fragment
       4, UNK               Unknown Layer 4 header
                            (compressed, encrypted, not supported)
       5, Res               Reserved
       6, HOP       0       Hop-by-hop option header
       7, DST      60       Destination option header
       8, PAY     108       Payload compression header
       9, AH       51       Authentication Header
      10, ESP      50       Encrypted security payload
      11 to 31              Reserved
         </artwork>
       </description>
       <reference>
         <paragraph>
         See RFC 2460 for the general definition of
         IPv6 extension headers and for the specification of
         the hop-by-hop options header, the routing header,
         the fragment header, and the destination options header.
         See RFC 4302 for the specification of the
         authentication header.
         See RFC 4303 for the specification of the
         encapsulating security payload.
         </paragraph>
       </reference>
     </field>

     <field name="tcpControlBits" dataType="unsigned8"
            dataTypeSemantics="flags"
            group="minMax"
            elementId="6" applicability="all" status="current">
       <description>
         <paragraph>
         TCP control bits observed for packets of this Flow.
         The information is encoded in a set of bit fields.
         For each TCP control bit, there is a bit in this
         set.  A bit is set to 1 if any observed packet of this
         Flow has the corresponding TCP control bit set to 1.
         A value of 0 for a bit indicates that the corresponding
         bit was not set in any of the observed packets
         of this Flow.
         </paragraph>
         <artwork>
          0     1     2     3     4     5     6     7
      +-----+-----+-----+-----+-----+-----+-----+-----+
      |  Reserved | URG | ACK | PSH | RST | SYN | FIN |
      +-----+-----+-----+-----+-----+-----+-----+-----+

      Reserved:  Reserved for future use by TCP.  Must be zero.
           URG:  Urgent Pointer field significant
           ACK:  Acknowledgment field significant
           PSH:  Push Function
           RST:  Reset the connection
           SYN:  Synchronize sequence numbers
           FIN:  No more data from sender
         </artwork>
       </description>
       <reference>
         <paragraph>
         See RFC 793 for the definition of
         the TCP control bits in the TCP header.
         </paragraph>
       </reference>
     </field>

     <field name="tcpOptions" dataType="unsigned64"
            dataTypeSemantics="flags"
            group="minMax"
            elementId="209" applicability="all" status="current">
       <description>
         <paragraph>
        TCP options in packets of this Flow.
        The information is encoded in a set of bit fields.  For
        each TCP option, there is a bit in this set.
        The bit is set to 1 if any observed packet of this Flow
        contains the corresponding TCP option.
        Otherwise, if no observed packet of this Flow contained
        the respective TCP option, the value of the
        corresponding bit is 0.
         </paragraph>
         <paragraph>
         Options are mapped to bits according to their option
         numbers.  Option number X is mapped to bit X.
         TCP option numbers are maintained by IANA.
         </paragraph>
         <artwork>
              0     1     2     3     4     5     6     7
          +-----+-----+-----+-----+-----+-----+-----+-----+
          |   0 |   1 |   2 |   3 |   4 |   5 |   6 |   7 |  ...
          +-----+-----+-----+-----+-----+-----+-----+-----+

              8     9    10    11    12    13    14    15
          +-----+-----+-----+-----+-----+-----+-----+-----+
      ... |   8 |   9 |  10 |  11 |  12 |  13 |  14 |  15 |...
          +-----+-----+-----+-----+-----+-----+-----+-----+

             16    17    18    19    20    21    22    23
          +-----+-----+-----+-----+-----+-----+-----+-----+
      ... |  16 |  17 |  18 |  19 |  20 |  21 |  22 |  23 |...
          +-----+-----+-----+-----+-----+-----+-----+-----+

                                . . .

             56    57    58    59    60    61    62    63
          +-----+-----+-----+-----+-----+-----+-----+-----+
      ... |  56 |  57 |  58 |  59 |  60 |  61 |  62 |  63 |
          +-----+-----+-----+-----+-----+-----+-----+-----+
         </artwork>
       </description>
       <reference>
         <paragraph>
         See RFC 793 for the definition of TCP options.
         See the list of TCP option numbers assigned by IANA
         at http://www.iana.org/assignments/tcp-parameters.
         </paragraph>
       </reference>
     </field>

     <field name="flowStartSeconds" dataType="dateTimeSeconds"
            group="timestamp"
            elementId="150" applicability="data" status="current">
       <description>
         <paragraph>
         The absolute timestamp of the first packet of this Flow.
         </paragraph>
       </description>
       <units>seconds</units>
     </field>

     <field name="flowEndSeconds" dataType="dateTimeSeconds"
            group="timestamp"
            elementId="151" applicability="data" status="current">
       <description>
         <paragraph>
         The absolute timestamp of the last packet of this Flow.
         </paragraph>
       </description>
       <units>seconds</units>
     </field>

     <field name="flowStartMilliseconds" dataType="dateTimeMilliseconds"
            group="timestamp"
            elementId="152" applicability="data" status="current">
       <description>
         <paragraph>
         The absolute timestamp of the first packet of this Flow.
         </paragraph>
       </description>
       <units>milliseconds</units>
     </field>

     <field name="flowEndMilliseconds" dataType="dateTimeMilliseconds"
            group="timestamp"
            elementId="153" applicability="data" status="current">
       <description>
         <paragraph>
         The absolute timestamp of the last packet of this Flow.
         </paragraph>
       </description>
       <units>milliseconds</units>
     </field>

     <field name="flowStartMicroseconds" dataType="dateTimeMicroseconds"
            group="timestamp"
            elementId="154" applicability="data" status="current">
       <description>
         <paragraph>
         The absolute timestamp of the first packet of this Flow.
         </paragraph>
       </description>
       <units>microseconds</units>
     </field>

     <field name="flowEndMicroseconds" dataType="dateTimeMicroseconds"
            group="timestamp"
            elementId="155" applicability="data" status="current">
       <description>
         <paragraph>
         The absolute timestamp of the last packet of this Flow.
         </paragraph>
       </description>
       <units>microseconds</units>
     </field>

     <field name="flowStartNanoseconds" dataType="dateTimeNanoseconds"
            group="timestamp"
            elementId="156" applicability="data" status="current">
       <description>
         <paragraph>
         The absolute timestamp of the first packet of this Flow.
         </paragraph>
       </description>
       <units>nanoseconds</units>
     </field>

     <field name="flowEndNanoseconds" dataType="dateTimeNanoseconds"
            group="timestamp"
            elementId="157" applicability="data" status="current">
       <description>
         <paragraph>
         The absolute timestamp of the last packet of this Flow.
         </paragraph>
       </description>
       <units>nanoseconds</units>
     </field>

     <field name="flowStartDeltaMicroseconds" dataType="unsigned32"
            group="timestamp"
            elementId="158" applicability="data" status="current">
       <description>
         <paragraph>
         This is a relative timestamp only valid within the scope
         of a single IPFIX Message.  It contains the negative time
         offset of the first observed packet of this Flow relative
         to the export time specified in the IPFIX Message Header.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See the IPFIX protocol specification [RFC5101] for the
         definition of the IPFIX Message Header.
         </paragraph>
       </reference>
       <units>microseconds</units>
     </field>

     <field name="flowEndDeltaMicroseconds" dataType="unsigned32"
            group="timestamp"
            elementId="159" applicability="data" status="current">
       <description>
         <paragraph>
         This is a relative timestamp only valid within the scope
         of a single IPFIX Message.  It contains the negative time
         offset of the last observed packet of this Flow relative
         to the export time specified in the IPFIX Message Header.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See the IPFIX protocol specification [RFC5101] for the
         definition of the IPFIX Message Header.
         </paragraph>
       </reference>
       <units>microseconds</units>
     </field>

     <field name="systemInitTimeMilliseconds"
            dataType="dateTimeMilliseconds"
            group="timestamp"
            elementId="160" applicability="data" status="current">
       <description>
         <paragraph>
         The absolute timestamp of the last (re-)initialization of the
         IPFIX Device.
         </paragraph>
       </description>
       <units>milliseconds</units>
     </field>

     <field name="flowStartSysUpTime" dataType="unsigned32"
            group="timestamp"
            elementId="22" applicability="data" status="current">
       <description>
         <paragraph>
         The relative timestamp of the first packet of this Flow.
         It indicates the number of milliseconds since the
         last (re-)initialization of the IPFIX Device (sysUpTime).
         </paragraph>
       </description>
       <units>milliseconds</units>
     </field>

     <field name="flowEndSysUpTime" dataType="unsigned32"
            group="timestamp"
            elementId="21" applicability="data" status="current">
       <description>
         <paragraph>
         The relative timestamp of the last packet of this Flow.

         It indicates the number of milliseconds since the
         last (re-)initialization of the IPFIX Device (sysUpTime).
         </paragraph>
       </description>
       <units>milliseconds</units>
     </field>

     <field name="octetDeltaCount" dataType="unsigned64"
            dataTypeSemantics="deltaCounter"
            group="flowCounter"
            elementId="1" applicability="data" status="current">
       <description>
         <paragraph>
         The number of octets since the previous report (if any)
         in incoming packets for this Flow at the Observation Point.
         The number of octets includes IP header(s) and IP payload.
         </paragraph>
       </description>
       <units>octets</units>
     </field>

     <field name="postOctetDeltaCount" dataType="unsigned64"
            dataTypeSemantics="deltaCounter"
            group="flowCounter"
            elementId="23" applicability="data" status="current">
       <description>
         <paragraph>
         The definition of this Information Element is identical
         to the definition of Information Element
         'octetDeltaCount', except that it reports a
         potentially modified value caused by a middlebox
         function after the packet passed the Observation Point.
         </paragraph>
       </description>
       <units>octets</units>
     </field>

     <field name="octetDeltaSumOfSquares" dataType="unsigned64"
            group="flowCounter"
            elementId="198" applicability="data" status="current">
       <description>
         <paragraph>
         The sum of the squared numbers of octets per incoming
         packet since the previous report (if any) for this
         Flow at the Observation Point.
         The number of octets includes IP header(s) and IP payload.
         </paragraph>
       </description>
     </field>

     <field name="octetTotalCount" dataType="unsigned64"
            dataTypeSemantics="totalCounter"
            group="flowCounter"
            elementId="85" applicability="all" status="current">
       <description>
         <paragraph>
         The total number of octets in incoming packets
         for this Flow at the Observation Point since the Metering
         Process (re-)initialization for this Observation Point.  The
         number of octets includes IP header(s) and IP payload.
         </paragraph>
       </description>
       <units>octets</units>
     </field>

     <field name="postOctetTotalCount" dataType="unsigned64"
            dataTypeSemantics="totalCounter"
            group="flowCounter"
            elementId="171" applicability="all" status="current">
       <description>
         <paragraph>
         The definition of this Information Element is identical
         to the definition of Information Element
         'octetTotalCount', except that it reports a
         potentially modified value caused by a middlebox
         function after the packet passed the Observation Point.
         </paragraph>
       </description>
       <units>octets</units>
     </field>

     <field name="octetTotalSumOfSquares" dataType="unsigned64"
            group="flowCounter"
            elementId="199" applicability="all" status="current">
       <description>
         <paragraph>
         The total sum of the squared numbers of octets in incoming
         packets for this Flow at the Observation Point since the
         Metering Process (re-)initialization for this Observation
         Point.  The number of octets includes IP header(s) and IP
         payload.
         </paragraph>
       </description>
       <units>octets</units>
     </field>
     <field name="packetDeltaCount" dataType="unsigned64"
            dataTypeSemantics="deltaCounter"
            group="flowCounter"
            elementId="2" applicability="data" status="current">
       <description>
         <paragraph>
         The number of incoming packets since the previous report
         (if any) for this Flow at the Observation Point.
         </paragraph>
       </description>
       <units>packets</units>
     </field>

     <field name="postPacketDeltaCount" dataType="unsigned64"
            dataTypeSemantics="deltaCounter"
            group="flowCounter"
            elementId="24" applicability="data" status="current">
       <description>
         <paragraph>
         The definition of this Information Element is identical
         to the definition of Information Element
         'packetDeltaCount', except that it reports a
         potentially modified value caused by a middlebox
         function after the packet passed the Observation Point.
         </paragraph>
       </description>
       <units>packets</units>
     </field>

     <field name="packetTotalCount" dataType="unsigned64"
            dataTypeSemantics="totalCounter"
            group="flowCounter"
            elementId="86" applicability="all" status="current">
       <description>
         <paragraph>
         The total number of incoming packets for this Flow
         at the Observation Point since the Metering Process
         (re-)initialization for this Observation Point.
         </paragraph>
       </description>
       <units>packets</units>
     </field>

     <field name="postPacketTotalCount" dataType="unsigned64"
            dataTypeSemantics="totalCounter"
            group="flowCounter"
            elementId="172" applicability="all" status="current">
       <description>
         <paragraph>
         The definition of this Information Element is identical
         to the definition of Information Element
         'packetTotalCount', except that it reports a
         potentially modified value caused by a middlebox
         function after the packet passed the Observation Point.
         </paragraph>
       </description>
       <units>packets</units>
     </field>

     <field name="droppedOctetDeltaCount" dataType="unsigned64"
            dataTypeSemantics="deltaCounter"
            group="flowCounter"
            elementId="132" applicability="data" status="current">
       <description>
         <paragraph>
         The number of octets since the previous report (if any)
         in packets of this Flow dropped by packet treatment.
         The number of octets includes IP header(s) and IP payload.
         </paragraph>
       </description>
       <units>octets</units>
     </field>

     <field name="droppedPacketDeltaCount" dataType="unsigned64"
            dataTypeSemantics="deltaCounter"
            group="flowCounter"
            elementId="133" applicability="data" status="current">
       <description>
         <paragraph>
         The number of packets since the previous report (if any)
         of this Flow dropped by packet treatment.
         </paragraph>
       </description>
       <units>packets</units>
     </field>

     <field name="droppedOctetTotalCount" dataType="unsigned64"
            dataTypeSemantics="totalCounter"
            group="flowCounter"
            elementId="134" applicability="data" status="current">
       <description>
         <paragraph>
         The total number of octets in packets of this Flow dropped
         by packet treatment since the Metering Process
         (re-)initialization for this Observation Point.
         The number of octets includes IP header(s) and IP payload.

         </paragraph>
       </description>
       <units>octets</units>
     </field>

     <field name="droppedPacketTotalCount" dataType="unsigned64"
            dataTypeSemantics="totalCounter"
            group="flowCounter"
            elementId="135" applicability="data" status="current">
       <description>
         <paragraph>
         The number of packets of this Flow dropped by packet
         treatment since the Metering Process
         (re-)initialization for this Observation Point.
         </paragraph>
       </description>
       <units>packets</units>
     </field>

     <field name="postMCastPacketDeltaCount" dataType="unsigned64"
            dataTypeSemantics="deltaCounter"
            group="flowCounter"
            elementId="19" applicability="data" status="current">
       <description>
         <paragraph>
         The number of outgoing multicast packets since the
         previous report (if any) sent for packets of this Flow
         by a multicast daemon within the Observation Domain.
         This property cannot necessarily be observed at the
         Observation Point, but may be retrieved by other means.
         </paragraph>
       </description>
       <units>packets</units>
     </field>

     <field name="postMCastOctetDeltaCount" dataType="unsigned64"
            dataTypeSemantics="deltaCounter"
            group="flowCounter"
            elementId="20" applicability="data" status="current">
       <description>
         <paragraph>
         The number of octets since the previous report (if any)
         in outgoing multicast packets sent for packets of this
         Flow by a multicast daemon within the Observation Domain.
         This property cannot necessarily be observed at the
         Observation Point, but may be retrieved by other means.
         The number of octets includes IP header(s) and IP payload.
         </paragraph>
       </description>
       <units>octets</units>
     </field>

     <field name="postMCastPacketTotalCount" dataType="unsigned64"
            dataTypeSemantics="totalCounter"
            group="flowCounter"
            elementId="174" applicability="data" status="current">
       <description>
         <paragraph>
         The total number of outgoing multicast packets sent for
         packets of this Flow by a multicast daemon within the
         Observation Domain since the Metering Process
         (re-)initialization.  This property cannot necessarily
         be observed at the Observation Point, but may be retrieved
         by other means.
         </paragraph>
       </description>
       <units>packets</units>
     </field>

     <field name="postMCastOctetTotalCount" dataType="unsigned64"
            dataTypeSemantics="totalCounter"
            group="flowCounter"
            elementId="175" applicability="data" status="current">
       <description>
         <paragraph>
         The total number of octets in outgoing multicast packets
         sent for packets of this Flow by a multicast daemon in the
         Observation Domain since the Metering Process
         (re-)initialization.  This property cannot necessarily be
         observed at the Observation Point, but may be retrieved by
         other means.
         The number of octets includes IP header(s) and IP payload.
         </paragraph>
       </description>
       <units>octets</units>
     </field>

     <field name="tcpSynTotalCount" dataType="unsigned64"
            dataTypeSemantics="totalCounter"
            group="flowCounter"
            elementId="218" applicability="data" status="current">
       <description>
         <paragraph>
          The total number of packets of this Flow with
          TCP "Synchronize sequence numbers" (SYN) flag set.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 793 for the definition of the TCP SYN flag.
         </paragraph>
       </reference>
       <units>packets</units>
     </field>

     <field name="tcpFinTotalCount" dataType="unsigned64"
            dataTypeSemantics="totalCounter"
            group="flowCounter"
            elementId="219" applicability="data" status="current">
       <description>
         <paragraph>
          The total number of packets of this Flow with
          TCP "No more data from sender" (FIN) flag set.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 793 for the definition of the TCP FIN flag.
         </paragraph>
       </reference>
       <units>packets</units>
     </field>

     <field name="tcpRstTotalCount" dataType="unsigned64"
            dataTypeSemantics="totalCounter"
            group="flowCounter"
            elementId="220" applicability="data" status="current">
       <description>
         <paragraph>
          The total number of packets of this Flow with
          TCP "Reset the connection" (RST) flag set.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 793 for the definition of the TCP RST flag.
         </paragraph>
       </reference>
       <units>packets</units>
     </field>

     <field name="tcpPshTotalCount" dataType="unsigned64"
            dataTypeSemantics="totalCounter"
            group="flowCounter"
            elementId="221" applicability="data" status="current">
       <description>
         <paragraph>
          The total number of packets of this Flow with
          TCP "Push Function" (PSH) flag set.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 793 for the definition of the TCP PSH flag.
         </paragraph>
       </reference>
       <units>packets</units>
     </field>

     <field name="tcpAckTotalCount" dataType="unsigned64"
            dataTypeSemantics="totalCounter"
            group="flowCounter"
            elementId="222" applicability="data" status="current">
       <description>
         <paragraph>
          The total number of packets of this Flow with
          TCP "Acknowledgment field significant" (ACK) flag set.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 793 for the definition of the TCP ACK flag.
         </paragraph>
       </reference>
       <units>packets</units>
     </field>

     <field name="tcpUrgTotalCount" dataType="unsigned64"
            dataTypeSemantics="totalCounter"
            group="flowCounter"
            elementId="223" applicability="data" status="current">
       <description>
         <paragraph>
          The total number of packets of this Flow with
          TCP "Urgent Pointer field significant" (URG) flag set.
         </paragraph>
       </description>
       <reference>
         <paragraph>
         See RFC 793 for the definition of the TCP URG flag.
         </paragraph>
       </reference>
       <units>packets</units>
     </field>

     <field name="flowActiveTimeout" dataType="unsigned16"
            group="misc"
            elementId="36" applicability="all" status="current">
       <description>
         <paragraph>
         The number of seconds after which an active Flow is timed out
         anyway, even if there is still a continuous flow of packets.
         </paragraph>
       </description>
       <units>seconds</units>
     </field>

     <field name="flowIdleTimeout" dataType="unsigned16"
            group="misc"
            elementId="37" applicability="all" status="current">
       <description>
         <paragraph>
          A Flow is considered to be timed out if no packets belonging
          to the Flow have been observed for the number of seconds
          specified by this field.
         </paragraph>
       </description>
       <units>seconds</units>
     </field>

     <field name="flowEndReason" dataType="unsigned8"
            group="misc"
            dataTypeSemantics="identifier"
            elementId="136" applicability="data" status="current">
       <description>
         <paragraph>
         The reason for Flow termination.  The range of values includes
         the following:
         </paragraph>
         <artwork>
      0x01: idle timeout
            The Flow was terminated because it was considered to be
            idle.
      0x02: active timeout
            The Flow was terminated for reporting purposes while it was
            still active, for example, after the maximum lifetime of
            unreported Flows was reached.
      0x03: end of Flow detected
            The Flow was terminated because the Metering Process
            detected signals indicating the end of the Flow,
            for example, the TCP FIN flag.
      0x04: forced end
            The Flow was terminated because of some external event,
            for example, a shutdown of the Metering Process initiated
            by a network management application.
      0x05: lack of resources
            The Flow was terminated because of lack of resources
            available to the Metering Process and/or the Exporting
            Process.
         </artwork>
       </description>
     </field>

     <field name="flowDurationMilliseconds" dataType="unsigned32"
            group="misc"
            elementId="161" applicability="data" status="current">
       <description>
         <paragraph>
         The difference in time between the first observed packet
         of this Flow and the last observed packet of this Flow.
         </paragraph>
       </description>
       <units>milliseconds</units>
     </field>

     <field name="flowDurationMicroseconds" dataType="unsigned32"
            group="misc"
            elementId="162" applicability="data" status="current">
       <description>
         <paragraph>
         The difference in time between the first observed packet
         of this Flow and the last observed packet of this Flow.
         </paragraph>
       </description>
       <units>microseconds</units>
     </field>

     <field name="flowDirection" dataType="unsigned8"
            dataTypeSemantics="identifier"
            group="misc"
            elementId="61" applicability="data" status="current">
       <description>
         <paragraph>
         The direction of the Flow observed at the Observation
         Point.  There are only two values defined.
         </paragraph>
         <artwork>
         0x00: ingress flow
         0x01: egress flow
         </artwork>
       </description>
     </field>

     <field name="paddingOctets" dataType="octetArray"
            group="padding"
            elementId="210" applicability="option" status="current">
       <description>
         <paragraph>
           The value of this Information Element is always a sequence of
           0x00 values.
         </paragraph>
       </description>
     </field>

   </fieldDefinitions>

Appendix B.  XML Specification of Abstract Data Types

   This appendix contains a machine-readable description of the abstract
   data types to be used for IPFIX Information Elements and a machine-
   readable description of the template used for defining IPFIX
   Information Elements.  Note that this appendix is of informational
   nature, while the text in Sections 2 and 3 (generated from this
   appendix) is normative.

   At the same time, this appendix is also an XML schema that was used
   for creating the XML specification of Information Elements in
   Appendix A.  It may also be used for specifying further Information
   Elements in extensions of the IPFIX information model.  This schema
   and its namespace are registered by IANA at
   http://www.iana.org/assignments/xml-registry/schema/ipfix.xsd.

   <?xml version="1.0" encoding="UTF-8"?>

   <schema targetNamespace="urn:ietf:params:xml:ns:ipfix-info-10"
           xmlns:ipfix="urn:ietf:params:xml:ns:ipfix-info-10"
           xmlns="http://www.w3.org/2001/XMLSchema"
           elementFormDefault="qualified">

     <simpleType name="dataType">
       <restriction base="string">
         <enumeration value="unsigned8">
           <annotation>
             <documentation>The type "unsigned8" represents a
               non-negative integer value in the range of 0 to 255.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="unsigned16">
           <annotation>
             <documentation>The type "unsigned16" represents a
               non-negative integer value in the range of 0 to 65535.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="unsigned32">
           <annotation>
             <documentation>The type "unsigned32" represents a
                non-negative integer value in the range of 0 to
                4294967295.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="unsigned64">
           <annotation>
             <documentation>The type "unsigned64" represents a
               non-negative integer value in the range of 0 to
               18446744073709551615.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="signed8">
           <annotation>
             <documentation>The type "signed8" represents
               an integer value in the range of -128 to 127.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="signed16">
           <annotation>
             <documentation>The type "signed16" represents an
               integer value in the range of -32768 to 32767.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="signed32">
           <annotation>
             <documentation>The type "signed32" represents an
                integer value in the range of -2147483648 to
                2147483647.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="signed64">
           <annotation>
             <documentation>The type "signed64" represents an
                integer value in the range of -9223372036854775808
                to 9223372036854775807.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="float32">
           <annotation>
             <documentation>The type "float32" corresponds to an IEEE
               single-precision 32-bit floating point type as defined
               in [IEEE.754.1985].
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="float64">
           <annotation>
             <documentation>The type "float64" corresponds to an IEEE
               double-precision 64-bit floating point type as defined
               in [IEEE.754.1985].
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="boolean">
           <annotation>
             <documentation>The type "boolean" represents a binary
               value.  The only allowed values are "true" and "false".
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="macAddress">
           <annotation>
             <documentation>The type "macAddress" represents a
               string of 6 octets.
             </documentation>
           </annotation>
         </enumeration>
         <enumeration value="octetArray">
           <annotation>
             <documentation>The type "octetArray" represents a
            finite-length string of octets.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="string">
           <annotation>
             <documentation>
               The type "string" represents a finite-length string
               of valid characters from the Unicode character encoding
               set [ISO.10646-1.1993].  Unicode allows for ASCII
               [ISO.646.1991] and many other international character
               sets to be used.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="dateTimeSeconds">
           <annotation>
             <documentation>
               The type "dateTimeSeconds" represents a time value
               in units of seconds normalized based on coordinated universal time
               (UTC).  The choice of an epoch, for example, 00:00 UTC,
               January 1, 1970, is left to corresponding encoding
               specifications for this type, for example, the
               GMT time zone. IPFIX
               protocol specification.  Leap seconds are excluded.
               Note that transformation of values might be required
               between different encoding if different epoch values
               are used.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="dateTimeMilliseconds">
           <annotation>
             <documentation>The type "dateTimeMilliseconds" represents
               a time value in units of milliseconds
               normalized
               based on coordinated universal time (UTC).
               The choice of an epoch, for example,  00:00 UTC,
               January 1, 1970, is left to corresponding encoding
               specifications for this type, for example, the GMT time zone. IPFIX
               protocol specification.  Leap seconds are excluded.
               Note that transformation of values might be required
               between different encoding if different epoch values
               are used.

             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="dateTimeMicroseconds">
           <annotation>
             <documentation>The type "dateTimeMicroseconds" represents
               a time value in units of microseconds
               normalized
               based on coordinated universal time (UTC).
               The choice of an epoch, for example,  00:00 UTC,
               January 1, 1970, is left to corresponding encoding
               specifications for this type, for example, the GMT time zone. IPFIX
               protocol specification.  Leap seconds are excluded.
               Note that transformation of values might be required
               between different encoding if different epoch values
               are used.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="dateTimeNanoseconds">
           <annotation>
             <documentation>The type "dateTimeNanoseconds" represents
               a time value in units of nanoseconds
               normalized
               based on coordinated universal time (UTC).
               The choice of an epoch, for example,  00:00 UTC,
               January 1, 1970, is left to corresponding encoding
               specifications for this type, for example, the GMT time zone. IPFIX
               protocol specification.  Leap seconds are excluded.
               Note that transformation of values might be required
               between different encoding if different epoch values
               are used.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="ipv4Address">
           <annotation>
             <documentation>The type "ipv4Address" represents a value
               of an IPv4 address.
             </documentation>
           </annotation>
         </enumeration>
         <enumeration value="ipv6Address">
           <annotation>
             <documentation>The type "ipv6Address" represents a value
               of an IPv6 address.
             </documentation>
           </annotation>
         </enumeration>
       </restriction>
     </simpleType>

     <simpleType name="dataTypeSemantics">
       <restriction base="string">
         <enumeration value="quantity">
           <annotation>
             <documentation>
               A quantity value represents a discrete
               measured value pertaining to the record.  This is
               distinguished from counters that represent an ongoing
               measured value whose "odometer" reading is captured as
               part of a given record.  If no semantic qualifier is
               given, the Information Elements that have an integral
               data type should behave as a quantity.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="totalCounter">
           <annotation>
             <documentation>
               An integral value reporting the value of a counter.
               Counters are unsigned and wrap back to zero after
               reaching the limit of the type.  For example, an
               unsigned64 with counter semantics will continue to
               increment until reaching the value of 2**64 - 1.  At
               this point, the next increment will wrap its value to
               zero and continue counting from zero.  The semantics
               of a total counter is similar to the semantics of
               counters used in SNMP, such as Counter32 defined in
               RFC 2578 [RFC2578].  The only difference between total
               counters and counters used in SNMP is that the total
               counters have an initial value of 0.  A total counter
               counts independently of the export of its value.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="deltaCounter">
           <annotation>
             <documentation>
               An integral value reporting the value of a counter.
               Counters are unsigned and wrap back to zero after
               reaching the limit of the type.  For example, an
               unsigned64 with counter semantics will continue to
               increment until reaching the value of 2**64 - 1.  At
               this point, the next increment will wrap its value to
               zero and continue counting from zero.  The semantics
               of a delta counter is similar to the semantics of
               counters used in SNMP, such as Counter32 defined in
               RFC 2578 [RFC2578].  The only difference between delta
               counters and counters used in SNMP is that the delta
               counters have an initial value of 0.  A delta counter
               is reset to 0 each time its value is exported.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="identifier">
           <annotation>
             <documentation>
               An integral value that serves as an identifier.
               Specifically
               Specifically, mathematical operations on two
               identifiers (aside from the equality operation) are
               meaningless.  For example, Autonomous System ID 1 *
               Autonomous System ID 2 is meaningless.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="flags">
           <annotation>
             <documentation>
               An integral value that actually represents a set of
               bit fields.  Logical operations are appropriate on
               such values, but not other mathematical operations.
               Flags should always be of an unsigned type.
             </documentation>
           </annotation>
         </enumeration>
       </restriction>
     </simpleType>

     <simpleType name="applicability">
       <restriction base="string">
         <enumeration value="data">
           <annotation>
             <documentation>
               Used for Information Elements that are applicable to
               Flow Records only.
             </documentation>
           </annotation>
         </enumeration>
         <enumeration value="option">
           <annotation>
             <documentation>
               Used for Information Elements that are applicable to
               option records only.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="all">
           <annotation>
             <documentation>
               Used for Information Elements that are applicable to
               Flow Records as well as to option records.
             </documentation>
           </annotation>
         </enumeration>
       </restriction>
     </simpleType>

     <simpleType name="status">
       <restriction base="string">
         <enumeration value="current">
           <annotation>
             <documentation>
               Indicates that the Information Element definition
               is current and valid.
             </documentation>
           </annotation>
         </enumeration>

         <enumeration value="deprecated">
           <annotation>
             <documentation>
               Indicates that the Information Element definition is
               obsolete, but it permits new/continued implementation
               in order to foster interoperability with older/existing
               implementations.
             </documentation>
           </annotation>
         </enumeration>
         <enumeration value="obsolete">
           <annotation>
             <documentation>
               Indicates that the Information Element definition is
               obsolete and should not be implemented and/or can be
               removed if previously implemented.
             </documentation>
           </annotation>
         </enumeration>
       </restriction>
     </simpleType>

     <complexType name="text">
       <choice maxOccurs="unbounded" minOccurs="0">
         <element name="paragraph">
           <complexType mixed="true">
             <sequence>
                <element maxOccurs="unbounded" minOccurs="0"
                  name="xref">
                  <complexType>
                    <attribute name="target" type="string"
                      use="required"/>
                  </complexType>
                </element>
             </sequence>
           </complexType>
         </element>
         <element name="artwork">
           <simpleType>
             <restriction base="string"/>
           </simpleType>
         </element>
       </choice>
     </complexType>

     <simpleType name="range">
       <restriction base="string"/>
     </simpleType>
     <element name="fieldDefinitions">
       <complexType>
         <sequence>
           <element maxOccurs="unbounded" minOccurs="1" name="field">
             <complexType>
               <sequence>
                 <element maxOccurs="1" minOccurs="1" name="description"
                          type="ipfix:text">
                   <annotation>
                     <documentation>
                       The semantics of this Information Element.
                       Describes how this Information Element is
                       derived from the Flow or other information
                       available to the observer.
                     </documentation>
                   </annotation>
                 </element>
                 <element maxOccurs="1" minOccurs="0" name="reference"
                          type="ipfix:text">
                   <annotation>
                     <documentation>
                       Identifies additional specifications that more
                       precisely define this item or provide additional
                       context for its use.
                     </documentation>
                   </annotation>
                 </element>

                 <element maxOccurs="1" minOccurs="0" name="units"
                          type="string">
                   <annotation>
                     <documentation>
                       If the Information Element is a measure of some
                       kind, the units identify what the measure is.
                     </documentation>
                   </annotation>
                 </element>

                 <element maxOccurs="1" minOccurs="0" name="range"
                          type="ipfix:range">
                   <annotation>
                     <documentation>
                       Some Information Elements may only be able to
                       take on a restricted set of values that can be
                       expressed as a range (e.g., 0 through 511
                       inclusive).  If this is the case, the valid
                       inclusive range should be specified.
                     </documentation>
                   </annotation>
                 </element>
               </sequence>

               <attribute name="name" type="string" use="required">
                 <annotation>
                   <documentation>
                     A unique and meaningful name for the Information
                     Element.
                   </documentation>
                 </annotation>
               </attribute>

               <attribute name="dataType" type="ipfix:dataType"
                          use="required">
                 <annotation>
                   <documentation>
                     One of the types listed in Section 3.1 of this
                     document or in a future extension of the
                     information model.  The type space for attributes
                     is constrained to facilitate implementation.  The
                     existing type space does however encompass most
                     basic types used in modern programming languages,
                     as well as some derived types (such as ipv4Address)
                     that are common to this domain and useful
                     to distinguish.
                   </documentation>
                 </annotation>
               </attribute>

               <attribute name="dataTypeSemantics"
                          type="ipfix:dataTypeSemantics" use="optional">
                 <annotation>
                   <documentation>
                     The integral types may be qualified by additional
                     semantic details.  Valid values for the data type
                     semantics are specified in Section 3.2 of this
                     document or in a future extension of the
                     information model.
                   </documentation>
                 </annotation>
               </attribute>

               <attribute name="elementId" type="nonNegativeInteger"
                          use="required">
                 <annotation>
                   <documentation>
                     A numeric identifier of the Information Element.
                     If this identifier is used without an enterprise
                     identifier (see [RFC5101] and
                     enterpriseId below), then it is globally unique
                     and the list of allowed values is administered by
                     IANA.  It is used for compact identification of an
                     Information Element when encoding Templates in the
                     protocol.
                   </documentation>
                 </annotation>
               </attribute>

               <attribute name="enterpriseId" type="nonNegativeInteger"
                          use="optional">
                 <annotation>
                   <documentation>
                     Enterprises may wish to define Information Elements
                     without registering them with IANA, for example,
                     for enterprise-internal purposes.  For such
                     Information Elements, the Information Element
                     identifier described above is not sufficient when
                     the Information Element is used outside the
                     enterprise.  If specifications of
                     enterprise-specific Information Elements are made
                     public and/or if enterprise-specific identifiers
                     are used by the IPFIX protocol outside the
                     enterprise, then the enterprise-specific
                     identifier MUST be made globally unique by
                     combining it with an enterprise identifier.
                     Valid values for the enterpriseId are
                     defined by IANA as Structure of Management
                     Information (SMI) network management private
                     enterprise codes.  They are defined at
                     http://www.iana.org/assignments/enterprise-numbers.
                   </documentation>
                 </annotation>
               </attribute>

               <attribute name="applicability"
                          type="ipfix:applicability" use="optional">
                 <annotation>
                   <documentation>
                     This property of an Information
                     Element indicates in which kind of records the
                     Information Element can be used.
                     Allowed values for this property are 'data',
                     'option', and 'all'.
                   </documentation>
                 </annotation>
               </attribute>

               <attribute name="status" type="ipfix:status"
                          use="required">
                 <annotation>
                   <documentation>
                     The status of the specification of this
                     Information Element.  Allowed values are 'current',
                     'deprecated', and 'obsolete'.
                   </documentation>
                 </annotation>
               </attribute>
               <attribute name="group" type="string"
                          use="required">
                 <annotation>
                   <documentation>to be done ...</documentation>
                 </annotation>
               </attribute>

             </complexType>
           </element>
         </sequence>
       </complexType>

       <unique name="infoElementIdUnique">
         <selector xpath="field"/>

         <field xpath="elementId"/>
       </unique>
     </element>
   </schema>

Authors' Addresses

   Juergen Quittek
   NEC
   Kurfuersten-Anlage 36
   Heidelberg 69115
   Germany

   Phone: +49 6221 90511-15
   EMail: quittek@nw.neclab.eu
   URI:   http://www.neclab.eu/

   Stewart Bryant
   Cisco Systems, Inc.
   250, Longwater Ave., Green Park
   Reading RG2 6GB
   United Kingdom

   EMail: stbryant@cisco.com

   Benoit Claise
   Cisco Systems, Inc.
   De Kleetlaan 6a b1
   Diegem 1831
   Belgium

   Phone: +32 2 704 5622
   EMail: bclaise@cisco.com

   Paul Aitken
   Cisco Systems, Inc.
   96 Commercial Quay
   Edinburgh EH6 6LX
   Scotland

   Phone: +44 131 561 3616
   EMail: paitken@cisco.com

   Jeff Meyer
   PayPal
   2211 N. First St.
   San Jose, CA 95131-2021
   US

   Phone: +1 408 976-9149
   EMail: jemeyer@paypal.com
   URI:   http://www.paypal.com

Full Copyright Statement

   Copyright (C) The IETF Trust (2007).

   This document is subject to the rights, licenses and restrictions
   contained in BCP 78, and except as set forth therein, the authors
   retain all their rights.

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   specification can be obtained from the IETF on-line IPR repository at
   http://www.ietf.org/ipr.

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