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Versions: (draft-claise-ipfix-information-model-rfc5102bis) 00 01 02 03 04 05 06 07 08 09 10 RFC 7012

Network Working Group                                     B. Claise, Ed.
Internet Draft                                       Cisco Systems, Inc.
Obsoletes: 5102                                         B. Trammell, Ed.
Category: Standards Track                                     ETH Zurich
Expires: May 24, 2013                                  November 20, 2012


        Information Model for IP Flow Information eXport (IPFIX)
          draft-ietf-ipfix-information-model-rfc5102bis-07.txt


Abstract

This document provides an overview of the information model for the IP
Flow Information eXport (IPFIX) protocol, as defined in the IANA IPFIX
Information Element Registry. 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. This document obsoletes RFC
5102.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF). Note that other groups may also distribute working
   documents as Internet-Drafts. The list of current Internet-Drafts is
   at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time. It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on March 23, 2012.

Copyright Notice

   Copyright (c) 2012 IETF Trust and the persons identified as the
   document authors. All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of



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   publication of this document. Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document. Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1. Changes since RFC 5102  . . . . . . . . . . . . . . . . . .  4
     1.2. IPFIX Documents Overview  . . . . . . . . . . . . . . . . .  4
   2.  Properties of IPFIX Protocol Information Elements  . . . . . .  5
     2.1.  Information Element Specification Template . . . . . . . .  5
     2.2.  Scope of Information Elements  . . . . . . . . . . . . . .  7
     2.3.  Naming Conventions for Information Elements  . . . . . . .  7
   3.  Type Space . . . . . . . . . . . . . . . . . . . . . . . . . .  8
     3.1.  Abstract Data Types  . . . . . . . . . . . . . . . . . . .  8
       3.1.1.  unsigned8  . . . . . . . . . . . . . . . . . . . . . .  8
       3.1.2.  unsigned16 . . . . . . . . . . . . . . . . . . . . . .  9
       3.1.3.  unsigned32 . . . . . . . . . . . . . . . . . . . . . .  9
       3.1.4.  unsigned64 . . . . . . . . . . . . . . . . . . . . . .  9
       3.1.5.  signed8  . . . . . . . . . . . . . . . . . . . . . . .  9
       3.1.6.  signed16 . . . . . . . . . . . . . . . . . . . . . . .  9
       3.1.7.  signed32 . . . . . . . . . . . . . . . . . . . . . . .  9
       3.1.8.  signed64 . . . . . . . . . . . . . . . . . . . . . . .  9
       3.1.9.  float32  . . . . . . . . . . . . . . . . . . . . . . .  9
       3.1.10.  float64 . . . . . . . . . . . . . . . . . . . . . . .  9
       3.1.11.  boolean . . . . . . . . . . . . . . . . . . . . . . . 10
       3.1.12.  macAddress  . . . . . . . . . . . . . . . . . . . . . 10
       3.1.13.  octetArray  . . . . . . . . . . . . . . . . . . . . . 10
       3.1.14.  string  . . . . . . . . . . . . . . . . . . . . . . . 10
       3.1.15.  dateTimeSeconds . . . . . . . . . . . . . . . . . . . 10
       3.1.16.  dateTimeMilliseconds  . . . . . . . . . . . . . . . . 10
       3.1.17.  dateTimeMicroseconds  . . . . . . . . . . . . . . . . 10
       3.1.18.  dateTimeNanoseconds . . . . . . . . . . . . . . . . . 10
       3.1.19.  ipv4Address . . . . . . . . . . . . . . . . . . . . . 10
       3.1.20.  ipv6Address . . . . . . . . . . . . . . . . . . . . . 11
     3.2.  Data Type Semantics  . . . . . . . . . . . . . . . . . . . 11
       3.2.1.  quantity . . . . . . . . . . . . . . . . . . . . . . . 11
       3.2.2.  totalCounter . . . . . . . . . . . . . . . . . . . . . 11
       3.2.3.  deltaCounter . . . . . . . . . . . . . . . . . . . . . 11
       3.2.4.  identifier . . . . . . . . . . . . . . . . . . . . . . 12
       3.2.5.  flags  . . . . . . . . . . . . . . . . . . . . . . . . 12
   4.  Information Element Identifiers  . . . . . . . . . . . . . . . 12
   5.  Information Elements . . . . . . . . . . . . . . . . . . . . . 13
   6.  Extending the Information Model  . . . . . . . . . . . . . . . 14



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   7.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 15
     7.1.  IPFIX Information Elements . . . . . . . . . . . . . . . . 15
     7.2.  MPLS Label Type Identifier . . . . . . . . . . . . . . . . 15
     7.3.  XML Namespace and Schema . . . . . . . . . . . . . . . . . 16
     7.4.  Addition, Revision, and Deprecation  . . . . . . . . . . . 17
   8.  Security Considerations  . . . . . . . . . . . . . . . . . . . 17
   9.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 18
   10.  References  . . . . . . . . . . . . . . . . . . . . . . . . . 18
     10.1.  Normative References  . . . . . . . . . . . . . . . . . . 18
     10.2.  Informative References  . . . . . . . . . . . . . . . . . 18
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 22





1.  Introduction

   The IP Flow Information eXport (IPFIX) protocol serves for
   transmitting information related to network traffic measurement. The
   protocol specification in [RFC5101bis] 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 [RFC5101bis].

   The canonical reference for IPFIX Information Elements the IANA IPFIX
   Information Element registry [IPFIX-IANA]; the initial values for
   this registry were provided by [RFC5102].

   This document complements the IPFIX protocol specification
   [RFC5101bis] by providing an overview of the IPFIX information model
   and specifying data types for it. IPFIX-specific terminology used in
   this document is defined in Section 2 of [RFC5101bis]. As in
   [RFC5101bis], 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. It also
   does not specify a concrete encoding of Information Elements; for an
   encoding suitable for use with the IPFIX protocol, see [RFC5101bis].
   Besides the encoding used by the IPFIX protocol, other encodings of
   IPFIX Information Elements can be applied, for example, XML-based
   encodings.



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   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].

1.1. Changes since RFC 5102

   This document obsoletes the Proposed Standard revision of the IPFIX
   Protocol Specification [RFC5102].  The following changes have been
   made to this document with respect to the previous document:

      - All outstanding technical and editorial errata filed on the
   [RFC5102] as of publication time have been corrected.
      - All references into [RFC5101] have been updated to [RFC5101bis],
   reflecting changes in that document as necessary.
      - Information element definitions have been removed, as the
   reference for these is now [IPFIX-IANA]; a historical note on
   categorizations of information elements as defined in [RFC5102] has
   been retained in section 5.
      - The process for modifying [IPFIX-IANA] has been improved, and is
   now described in [IPFIX-IE-DOCTORS]; Section 6 has been updated
   accordingly, and a new section 7.3 gives IANA considerations for this
   process.
      - Definitions of timestamp data types have been clarified.
      - Appendices A and B have been removed

1.2. IPFIX Documents Overview

   The IPFIX protocol provides network administrators with access to
   network flow information.  The architecture for the export of
   measured flow information out of an IPFIX Exporting Process to a
   Collecting Process is defined in [RFC5470], per the requirements
   defined in [RFC3917].  The IPFIX Protocol Specification [RFC5101bis]
   defines how IPFIX data records and templates are carried via a number
   of transport protocols from IPFIX Exporting Processes to IPFIX
   Collecting Processes.

   Four IPFIX optimizations/extensions are currently specified: a
   bandwidth saving method for the IPFIX protocol in [RFC5473], an
   efficient method for exporting bidirectional flows in [RFC5103], a
   method for the definition and export of complex data structures in
   [RFC6313], and the specification of the Protocol for IPFIX Mediations
   [IPFIX-MED-PROTO] based on the IPFIX Mediation Framework [RFC6183].

   IPFIX has a formal description of IPFIX Information Elements, their
   name, type and additional semantic information, as specified in this
   document, with the export of the Information Element types specified
   in [RFC5610].




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   [RFC6728] specifies a data model for configuring and monitoring IPFIX
   and PSAMP compliant devices using the NETCONF protocol, while
   [RFC6615] specifies a MIB module for monitoring.

   In terms of development, [RFC5153] provides guidelines for the
   implementation and use of the IPFIX protocol, while [RFC5471]
   provides guidelines for testing.

   Finally, [RFC5472] describes what type of applications can use the
   IPFIX protocol and how they can use the information provided.  It
   furthermore shows how the IPFIX framework relates to other
   architectures and frameworks.

2.  Properties of IPFIX Protocol Information Elements

2.1.  Information Element Specification Template

   Information in messages of the IPFIX protocol is modeled in terms of
   Information Elements of the IPFIX information model. The IPFIX
   Information Elements mentioned in Section 5 are specified in [IPFIX-
   IANA].

   All Information Elements specified for the IPFIX protocol 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
      [RFC5101bis] 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. Information Elements of
      dataType string or octetArray which have length constraints (fixed
      length, minimum and/or maximum length) MUST note these constraints
      in their description.

   dataType - One of the types listed in Section 3.1 of this document or
      registered in the IANA IPFIX Information Element Data Types
      registry. The type space for attributes is constrained to
      facilitate implementation. The existing type space encompasses
      most primitive types used in modern programming languages, as well
      as some derived types (such as ipv4Address) that are common to
      this domain.



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   status - The status of the specification of this Information Element.
      Allowed values are 'current' and 'deprecated'. All newly-defined
      Information Elements have 'current' status. The process for moving
      Information Elements to the 'deprecated' status is defined in
      Section 5.2 of [IPFIX-IE-DOCTORS].

   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 numbers,
      defined at [PEN-IANA].

   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 are 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; values for this Information Element
      outside the range are invalid and MUST NOT be exported.

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


   The following two Information Element properties are defined to allow
   the management of an Information Element registry with Information
   Element definitions that may be updated over time, per the process



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   defined in Section 5.2 of [IPFIX-IE-DOCTORS].

   revision - The revision number of an Information Element, starting at
      0 for Information Elements at time of definition, and incremented
      by one for each revision.

   date - The date of the entry of this revision of the Information
      Element into the registry.

   A template for specifying Information Elements in Internet-Drafts is
   given in Section 9.1 of [IPFIX-IE-DOCTORS], and an XML Schema for
   specifying Information Elements in the IANA IPFIX registry [IPFIX-
   IANA] at [IPFIX-XML-SCHEMA].

2.2.  Scope of Information Elements

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

   o  The Information Elements listed in Sections 5.2 and 5.3, and
      similar Information Elements in [IPFIX-IANA], have a default of "a
      specific Metering Process" or of "a specific Exporting Process",
      respectively.

   o  The Information Elements listed in Sections 5.4-5.11, and similar
      Information Elements in [IPFIX-IANA], 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 [RFC5101bis].

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 MUST be unique within the IANA IPFIX
      registry [IPFIX-IANA]. Enterprise-specific Information Elements
      SHOULD be prefixed with a vendor name.

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



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   o  Composed names MUST 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 letters, 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 ipClassOfService.  Then the value observed and
      reported by Information Element ipClassOfService 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, "postIpClassOfService".  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 updates to this document. Changes to the
   associated IPFIX Information Element Data Types subregistry [IPFIX-
   IANA] specified in [RFC5610] require a Standards Action [RFC5226].

3.1.1.  unsigned8




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   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].




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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 data type dateTimeSeconds is an unsigned 32-bit integer
   representing the number of seconds since the UNIX epoch, 1 January
   1970 at 00:00 UTC, as defined in [POSIX.1].

3.1.16.  dateTimeMilliseconds

   The data type dateTimeMilliseconds is an unsigned 64-bit integer
   containing the number of milliseconds since the UNIX epoch, 1 January
   1970 at 00:00 UTC, as defined in [POSIX.1].

3.1.17.  dateTimeMicroseconds

   The type "dateTimeMicroseconds" represents a time value with
   microsecond precision according to the NTP Timestamp format as
   defined in section 6 of [RFC5905].

3.1.18.  dateTimeNanoseconds

   The type "dateTimeNanoseconds" represents a time value with
   nanosecond precision according to the NTP Timestamp format as defined
   in section 6 of [RFC5905].

3.1.19.  ipv4Address

   The type "ipv4Address" represents an IPv4 address.




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3.1.20.  ipv6Address

   The type "ipv6Address" represents an IPv6 address.

3.2.  Data Type Semantics

   This section describes the set of valid data type semantics of the
   IPFIX information model. A sub-registry of data type semantics
   [IPFIX-IANA] is established in [RFC5610]; the restrictions on the use
   of semantics below are compatible with those specified in section
   3.10 of that document. These semantics apply only to numeric types,
   as noted in the description of each semantic below.

   Further data type semantics may be specified by future updates to
   this document.  Changes to the associated IPFIX Information Element
   Semantics sub-registry [IPFIX-IANA] require a Standards Action
   [RFC5226].

3.2.1.  quantity

   A numeric (integral or floating point) value representing a 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. This is the default semantic type
   of all numeric data types.

3.2.2.  totalCounter

   An numeric 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 [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 numeric 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



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   [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 it is exported and/or expires
   without export.

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. Identifiers MUST be one of the
   signed or unsigned data types.

3.2.5.  flags

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

4.  Information Element Identifiers

   All Information Elements defined in the IANA IPFIX Information
   Element registry [IPFIX-IANA] have their identifiers assigned by
   IANA.

   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]; Information Element identifiers in this range MUST NOT be
   assigned unless the Information Element is compatible with the
   NetFlow version 9 protocol. Such Information Elements may ONLY be
   requested by a NetFlow v9 expert, to be designated by the IESG.

   In general, IANA will add newly registered Information Elements to
   the registry, assigning the lowest available Information Element
   identifier in the range 128-32767.

   Enterprise-specific Information Element identifiers have the same
   range of 1-32767, but they are coupled with an additional enterprise
   identifier. For enterprise-specific Information Elements, Information
   Element identifier 0 is also reserved. 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; these
   Information Elements are distinct because the Information Element
   identifier is coupled with an enterprise identifier.

   Enterprise identifiers MUST be registered as SMI network management



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   private enterprise code numbers with IANA.  The registry can be found
   at [PEN-IANA].

5.  Information Elements

   [IPFIX-IANA] is now the normative reference for IPFIX Information
   Elements. At the time of publication of [RFC5102], this section
   defined the initial contents of that registry.

   As a historical note, Information Elements were organized into 12
   categories in [RFC5102] according to their semantics and their
   applicability; these categories were not carried forward into [IPFIX-
   IANA] as an organizing principle. The categories (with example IEs)
   were:

   1.   Identifiers (e.g. ingressInterface)
   2.   Metering and Exporting Process Configuration
          (e.g. exporterIPv4Address)
   3.   Metering and Exporting Process Statistics
          (e.g. exportedOctetTotalCount)
   4.   IP Header Fields (e.g. sourceIPv4Address)
   5.   Transport Header Fields (e.g. sourceTransportPort)
   6.   Sub-IP Header Fields (e.g. sourceMacAddress)
   7.   Derived Packet Properties (e.g. bgpSourceAsNumber)
   8.   Min/Max Flow Properties (e.g. minimumIpTotalLength)
   9.   Flow Timestamps (e.g. flowStartTimeMilliseconds)
   10.  Per-Flow Counters (e.g. octetDeltaCount)
   11.  Miscellaneous Flow Properties (e.g. flowEndReason)
   12.  Padding (paddingOctets)

   Information Elements derived from fields of packets or from packet
   treatment can typically serve as Flow Keys used for mapping packets
   to Flows. These Information Elements were placed in categories 4-7 in
   the original categorization.

   Information Elements not serving as Flow Keys may have different
   values for each packet in a Flow. For Information Elements with
   values derived from packets fields or packet treatment, and for which
   the value may change from packet to packet within a single Flow, the
   exported value of an Information Element is by default determined by
   the first packet observed for the corresponding Flow; the description
   of the Information Element may however explicitly specify 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 need to be updated;
   these Information Elements were placed in categories 8-11 in the
   original categorization.



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   Information Elements with a name having the "post" prefix (e.g.
   postIpClassOfService), do not necessarily report properties that were
   actually observed at the Observation Point, but may be 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; they may also be reported directly by the Observation Point if
   the Observation Point is situated such as to observe packets on both
   sides of the middlebox.


6.  Extending the Information Model

   A key requirement for IPFIX is to allow for extension of the
   Information Model via the IANA IPFIX registry [IPFIX-IANA]. New
   Information Element definitions can be added to this registry subject
   to an Expert Review [RFC5226], with additional process considerations
   decribed in [IPFIX-IE-DOCTORS]; that document also provides
   guidelines for authors and reviewers of new Information Element
   definitions.

   For new Information Elements, the type space defined in Section 3 can
   be used. If required, new abstract data types can be added to the
   data type subregistry [IPFIX-IANA] defined in [RFC5610]. New abstract
   data types and semantics are subject to Standards Action [RFC5226],
   and MUST be defined in IETF Standards Track documents updating this
   document.

   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; guidelines
   for using them appear in [IPFIX-IE-DOCTORS].


















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7.  IANA Considerations

7.1.  IPFIX Information Elements

This document refers to Information Elements, for which the Internet
Assigned Numbers Authority (IANA) has created the IPFIX Information
Element Registry [IPFIX-IANA]. The columns of this registry must at
minimum be able to store the information defined in the template in
Section 2.1; it may contain other information as necessary for the
management of the registry.

New assignments for IPFIX Information Elements are administered by IANA
through Expert Review [RFC5226], i.e., review by one of a group of
experts designated by the IESG. Further considerations for this review
are specified in [IPFIX-IE-DOCTORS].

Future assignments added to the IPFIX Information Element Registry which
require subregistries for enumerated values (e.g. section 7.2, below)
must have those subregistries added simultaneously with the new
assignment; additions to these subregistries must be subject to Expert
Review [RFC5226]. Unless specified at assignment time, the experts for
the subregistry will be the same as for the Information Element registry
as a whole.

Changes may also be made to the entries in this registry from time to
time; the process for these changes are specified in [IPFIX-IE-DOCTORS].

[NOTE to IANA: please update the Reference for the IPFIX Information
Element Registry to refer to this document.]

[NOTE to IANA: on publication of this document, please set the Revision
of all existing Information Elements to 0.]

[NOTE to IANA: on publication of this document, please set the Date of
all existing Information Elements to the publication date of this
document.]

[NOTE to IANA: on publication of this document, please set the Name of
all existing Reserved Information Elements to "Assigned for NetFlow v9
compatibility", and the reference to [RFC3954].]

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
subregistry for MPLS label types and filled it with the initial list
from the description Information Element #46, mplsTopLabelType.



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New assignments for MPLS label types are administered by IANA through
Expert Review [RFC5226], 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.

[NOTE to IANA: please update the Reference for the IPFIX MPLS Label Type
subregistry to refer to this document.]

7.3.  XML Namespace and Schema

[IPFIX-XML-SCHEMA] defines an XML schema for IPFIX Information Element
definitions.  All Information Elements specified in [IPFIX-IANA] are
defined by this schema.  This schema may also be used for specifying
further Information Elements in future extensions of the IPFIX
information model in a machine-readable way.

[IPFIX-XML-SCHEMA] 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
    *  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
    *  Registrant Contact: IETF IPFIX Working Group <ipfix@ietf.org>,
       as designated by the IESG <iesg@ietf.org>.

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



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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.

[NOTE to IANA: please update the Reference for the the IPFIX
information model namespace and schema to refer to this document.]

7.4.  Addition, Revision, and Deprecation

As stated in Section 6, addition, revision, and deletion of Information
Elements in the IPFIX Information Element registry is subject to a
process described in [IPFIX-IE-DOCTORS]. The IE-DOCTORS experts
mentioned in this process are to be appointed by the IESG.

When IANA receives a request to add, revise, or deprecate an Information
Element in the IPFIX Information Elements Registry, it forwards the
request to the IE-DOCTORS experts for review.

When IANA receives an approval for a request to add an Information
Element definition from the IE-DOCTORS experts, it adds that Information
Element to the registry. The approved request may include changes made
by the requestor and/or reviewers as compared to the original request.

When IANA receives an approval for a request to revise an Information
Element definition from the IE-DOCTORS experts, it changes that
Information Element's definition in the registry, and updates the
Revision and Date columns as appropriate. The approved request may
include changes from the original request. If the original Information
Element was added to the registry with IETF consensus (i.e., was defined
by an RFC), the revision will require IETF consensus as well.

When IANA receives an approval for a request to deprecate an Information
Element definition from the IE-DOCTORS experts, it changes that
Information Element's definition in the registry, and updates the
Revision and Date columns as appropriate. The approved request may
include changes from the original request. If the original Information
Element was added to the registry with IETF consensus (i.e., was defined
by an RFC), the deprecation will require IETF consensus as well.


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.




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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
[RFC5101bis].

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 would like to thank the authors of [RFC5102], as this
document is directly based upon this original RFC: Juergen Quittek,
Stewart Bryant, Paul Aitken, and Jeff Meyer. Thanks to Paul Aitken for
his detailed review.

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.

   [RFC5905]  Mills, D., Delaware, U., Martin, J., Burbank, J. and W.
              Kasch, "Network Time Protocol Version 4: Protocol and
              Algorithms Specification", RFC 5905, June 2010

   [RFC5101bis]
              Claise, B., and B. Trammell, Editors, "Specification of
              the IP Flow Information eXport (IPFIX) Protocol for the
              Exchange of IP Traffic Flow Information", draft-ietf-
              ipfix-protocol-rfc5101bis-02, Work in Progress, June 2012.

   [IPFIX-IE-DOCTORS]
              Trammell, B., and B. Claise, "Guidelines for Authors and
              Reviewers of IPFIX Information Elements", draft-ietf-
              ipfix-ie-doctors-07, Work in Progress, October 2012.

10.2.  Informative References

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



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              Standard 754, August 1985.

   [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.


   [POSIX.1]  IEEE 1003.1-2008 - IEEE Standard for Information
              Technology - Portable Operating System Interface, IEEE,
              2008.

   [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.

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

   [RFC3917]  Quittek, J., Zseby, T., Claise, B., and S. Zander,
              "Requirements for IP Flow Information Export (IPFIX)", RFC
              3917, October 2004.

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

   [RFC5101]  Claise, B., Bryant, S., Leinen, S., Dietz, T., and
              Trammell, B., "Specification of the IPFIX Protocol for the
              Exchange of IP Traffic Flow Information", RFC 5101,
              January 2008.

   [RFC5102]  Quittek, J., Bryant, S. Claise, B., Aitken, P., and Meyer,



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              J., "Information Model for IP Flow Information Export",
              RFC 5102, January 2008.

   [RFC5103]  Trammell, B., and E. Boschi, "Bidirectional Flow Export
              Using IP Flow Information Export (IPFIX)", RFC 5103,
              January 2008.

   [RFC5153]  Boschi, E., Mark, L., Quittek J., and P. Aitken, "IP Flow
              Information Export (IPFIX) Implementation Guidelines",
              RFC5153, April 2008.

   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 5226,
              May 2008.

   [RFC5470]  Sadasivan, G., Brownlee, N., Claise, B., and J. Quittek,
              "Architecture for IP Flow Information Export", RFC5470,
              March 2009.

   [RFC5471]  Schmoll, C., Aitken, P., and B. Claise, "Guidelines for IP
              Flow Information Export (IPFIX) Testing", RFC5471, March
              2009.

   [RFC5472]  Zseby, T., Boschi, E., Brownlee, N., and B. Claise, "IP
              Flow Information Export (IPFIX) Applicability", RFC5472,
              March 2009.

   [RFC5473]  Boschi, E., Mark, L., and B. Claise, "Reducing Redundancy
              in IP Flow Information Export (IPFIX) and Packet Sampling
              (PSAMP) Reports", RFC5473, March 2009.

   [RFC5610]  Boschi, E., Trammell, B., Mark, L., and T. Zseby,
              "Exporting Type Information for IP Flow Information Export
              (IPFIX) Information Elements", July 2009.

   [RFC6183]  Kobayashi, A., Claise, B., Muenz, G, and K. Ishibashi, "IP
              Flow Information Export (IPFIX) Mediation: Framework",
              RFC6183, April 2011.

   [RFC6313]  Claise, B., Dhandapani, G., Aitken, P, and S. Yates,
              "Export of Structured Data in IP Flow Information Export
              (IPFIX)", RFC6313, July 2011.

   [RFC6615]
              Dietz, T., Kobayashi, A., Claise, B., and G. Muenz,
              "Definitions of Managed Objects for IP Flow Information
              Export", RFC6615, June 2012.




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   [RFC6728]
              Muenz, G., Claise, B., and P. Aitken, "Configuration Data
              Model for IPFIX and PSAMP", RFC 6728, October 2012.

   [IPFIX-MED-PROTO]
              Claise, B., Kobayashi, A., and B. Trammell, "Operation of
              the IP Flow Information Export (IPFIX) Protocol on IPFIX
              Mediators", draft-ietf-ipfix-mediation-protocol-02, Work
              in Progress, July 2012.

   [IPFIX-IANA]
              http://www.iana.org/assignments/ipfix/ipfix.xml

   [PEN-IANA]
              http://www.iana.org/assignments/enterprise-numbers

   [IPFIX-XML-SCHEMA]
              http://www.iana.org/assignments/xml-
              registry/schema/ipfix.xsd
































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Authors' Addresses

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

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


   Brian Trammell
   Swiss Federal Institute of Technology Zurich
   Gloriastrasse 35
   8092 Zurich
   Switzerland

   Phone: +41 44 632 70 13
   EMail: trammell@tik.ee.ethz.ch































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