ftp.cc.uoc.gr
rfc7012
This is a purely informative rendering of an RFC that includes verified errata. This rendering may not be used as a reference.

The following 'Verified' errata have been incorporated in this document: EID 3881
Internet Engineering Task Force (IETF)                    B. Claise, Ed.
Request for Comments: 7012                           Cisco Systems, Inc.
Obsoletes: 5102                                         B. Trammell, Ed.
Category: Standards Track                                     ETH Zurich
ISSN: 2070-1721                                           September 2013


        Information Model for IP Flow Information Export (IPFIX)

Abstract

   This document defines the data types and management policy for the
   information model for the IP Flow Information Export (IPFIX)
   protocol.  This information model is maintained as the IANA "IPFIX
   Information Elements" registry, the initial contents of which were
   defined by RFC 5102.  This information model 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 this model was
   developed for the IPFIX protocol, it is defined in an open way that
   allows it to be easily used in other protocols, interfaces, and
   applications.  This document obsoletes RFC 5102.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc7012.

Copyright Notice

   Copyright (c) 2013 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
   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 ................8
   3. Type Space ......................................................9
      3.1. Abstract Data Types ........................................9
           3.1.1. unsigned8 ...........................................9
           3.1.2. unsigned16 ..........................................9
           3.1.3. unsigned32 ..........................................9
           3.1.4. unsigned64 ..........................................9
           3.1.5. signed8 ............................................10
           3.1.6. signed16 ...........................................10
           3.1.7. signed32 ...........................................10
           3.1.8. signed64 ...........................................10
           3.1.9. float32 ............................................10
           3.1.10. float64 ...........................................10
           3.1.11. boolean ...........................................10
           3.1.12. macAddress ........................................10
           3.1.13. octetArray ........................................10
           3.1.14. string ............................................11
           3.1.15. dateTimeSeconds ...................................11
           3.1.16. dateTimeMilliseconds ..............................11
           3.1.17. dateTimeMicroseconds ..............................11
           3.1.18. dateTimeNanoseconds ...............................11
           3.1.19. ipv4Address .......................................11
           3.1.20. ipv6Address .......................................11

           3.1.21. basicList .........................................11
           3.1.22. subTemplateList ...................................11
           3.1.23. subTemplateMultiList ..............................12
      3.2. Data Type Semantics .......................................12
           3.2.1. quantity ...........................................12
           3.2.2. totalCounter .......................................12
           3.2.3. deltaCounter .......................................12
           3.2.4. identifier .........................................13
           3.2.5. flags ..............................................13
   4. Information Element Identifiers ................................13
   5. Information Elements ...........................................14
   6. Extending the Information Model ................................15
   7. IANA Considerations ............................................15
      7.1. IPFIX Information Elements ................................16
      7.2. MPLS Label Type Identifier ................................17
      7.3. XML Namespace and Schema ..................................17
      7.4. Addition, Revision, and Deprecation .......................18
   8. Security Considerations ........................................19
   9. Acknowledgments ................................................19
   10. References ....................................................19
      10.1. Normative References .....................................19
      10.2. Informative References ...................................20
   Contributors ......................................................23

1.  Introduction

   The IP Flow Information Export (IPFIX) protocol serves as a means for
   transmitting information related to network traffic measurement.  The
   IPFIX Protocol Specification [RFC7011] defines how Information
   Elements are transmitted and also specifies the encoding of a set of
   basic data types for these Information Elements.  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 Process and Exporting Process (packet
   Observation Point, sampling rate, Flow timeout interval, etc.), is
   not specified in [RFC7011].

   The IANA "IPFIX Information Elements" registry [IANA-IPFIX] is the
   current complete reference for IPFIX Information Elements.  The
   initial values for this registry were provided by [RFC5102].

   This document complements the IPFIX Protocol Specification [RFC7011]
   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 [RFC7011].  As in [RFC7011],
   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], as the IPFIX information model
   does not specify relationships between Information Elements, nor does
   it specify a concrete encoding of Information Elements.  For an
   encoding suitable for use with the IPFIX protocol, see [RFC7011].
   Besides the encoding used by the IPFIX protocol, other encodings of
   IPFIX Information Elements can be applied, for example, XML-based
   encodings.

   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
   information model specification [RFC5102].  The following changes
   have been made to this document with respect to the previous
   document:

   - At the time of this publication, technical and editorial errata
     reported for [RFC5102] have been reviewed and addressed as needed.

   - All references to [RFC5101] have been updated to [RFC7011],
     reflecting changes to [RFC5101].

   - Information Element definitions have been removed, as the reference
     for these is now [IANA-IPFIX]; a historical note on categorizations
     of Information Elements as defined in [RFC5102] has been retained
     in Section 5.

   - The process for modifying [IANA-IPFIX] has been improved and is now
     described in [RFC7013]; Section 6 has been updated accordingly, and
     a new Section 7.3 provides 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 [RFC7011]

   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 [RFC5473], an
   efficient method for exporting bidirectional flows [RFC5103], a
   method for the definition and export of complex data structures
   [RFC6313], and the specification of the Protocol on IPFIX Mediators
   [IPFIX-MED-PROTO] based on the IPFIX Mediation Framework [RFC6183].

   IPFIX has a formal description of IPFIX Information Elements -- their
   names, data types, and additional semantic information -- as
   specified in this document.  The export of the Information Element
   types is specified in [RFC5610].

   [RFC6728] specifies a data model for configuring and monitoring
   devices that are IPFIX and Packet Sampling (PSAMP) compliant using
   the Network Configuration Protocol (NETCONF), while [RFC6615]
   specifies MIB modules 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 types 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
   [IANA-IPFIX].

   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 [RFC7011]
      and the definition of enterpriseId listed 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 that have length constraints (fixed
      length, minimum and/or maximum length) MUST note these constraints
      in their descriptions.

   dataType - One of the types listed in Section 3.1 of this document or
      registered in the IANA "IPFIX Information Element Data Types"
      subregistry.  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.

   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 5.3 of [RFC7013].

   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
      [IANA-PEN].

   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
      either specified in Section 3.2 of this document or will be
      specified 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 Elements registry with Information
   Element definitions that may be updated over time, per the process
   defined in Section 5.2 of [RFC7013]:

   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 is given in
   Section 9.1 of [RFC7013].

2.2.  Scope of Information Elements

   By default, most Information Elements have a scope specified in their
   definitions.  Within Data Records defined by Options 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 [RFC7011].

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 "IPFIX
      Information Elements" registry [IANA-IPFIX].  Enterprise-specific
      Information Elements SHOULD be prefixed with a vendor name.

   o  Names of Information Elements MUST start with lowercase letters.

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

   o  Middleboxes [RFC3234] may change Flow properties, such as the
      Differentiated Services 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 that 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, independent of encoding.  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 [IANA-IPFIX] specified in [RFC5610] require a
   Standards Action [RFC5226].

   The abstract data type definitions in this section are intended  
only to define the values which can be taken by Information 
Elements of each type. The encodings of these data types for 
use with the IPFIX protocol are defined in Section 6.1 of 
[RFC7011]; encodings allowing the use of the IPFIX Information 
Elements [IANA-IPFIX] with other protocols may be defined in 
the future by referencing this document. Note that for timestamp 
encodings (sections 3.1.15 - 3.1.18), it is the responsibility of 
the encoding to ensure that each representation has an 
unambiguous mapping to a moment in time (e.g. relative to a 
defined epoch).
EID 3881 (Verified) is as follows:

Section: 3.1

Original Text:

The current encodings of these data types for use with the IPFIX 
protocol are defined in [RFC7011]; encodings allowing the use of 
the IPFIX Information Elements [IANA-IPFIX] with other protocols 
may be defined in the future by referencing this document.

Corrected Text:

The abstract data type definitions in this section are intended 
only to define the values which can be taken by Information 
Elements of each type. The encodings of these data types for 
use with the IPFIX protocol are defined in Section 6.1 of 
[RFC7011]; encodings allowing the use of the IPFIX Information 
Elements [IANA-IPFIX] with other protocols may be defined in 
the future by referencing this document. Note that for timestamp 
encodings (sections 3.1.15 - 3.1.18), it is the responsibility of 
the encoding to ensure that each representation has an 
unambiguous mapping to a moment in time (e.g. relative to a 
defined epoch).
Notes:
The separation of epoch selection between ADT and encoding in 7011 and 7012 (as compared to 5101 and 5102, which they obsolete, respectively) led to it being unclear that timestamp ADTs require a fixed reference epoch for interpretation. This change clarifies the point, replacing Errata ID 3852.
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.754.2008]. 3.1.10. float64 The type "float64" corresponds to an IEEE double-precision 64-bit floating-point type as defined in [IEEE.754.2008]. 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 MAC-48 address as defined in [IEEE.802-3.2012]. 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 coded character set [ISO.10646]. Unicode incorporates ASCII [RFC20] and the characters of many other international character sets. 3.1.15. dateTimeSeconds The type "dateTimeSeconds" represents a time value expressed with second-level precision. 3.1.16. dateTimeMilliseconds The type "dateTimeMilliseconds" represents a time value expressed with millisecond-level precision. 3.1.17. dateTimeMicroseconds The type "dateTimeMicroseconds" represents a time value expressed with microsecond-level precision. 3.1.18. dateTimeNanoseconds The type "dateTimeNanoseconds" represents a time value expressed with nanosecond-level precision. 3.1.19. ipv4Address The type "ipv4Address" represents an IPv4 address. 3.1.20. ipv6Address The type "ipv6Address" represents an IPv6 address. 3.1.21. basicList The type "basicList" supports structured data export as described in [RFC6313]; see Section 4.5.1 of that document for encoding details. 3.1.22. subTemplateList The type "subTemplateList" supports structured data export as described in [RFC6313]; see Section 4.5.2 of that document for encoding details. 3.1.23. subTemplateMultiList The type "subTemplateMultiList" supports structured data export as described in [RFC6313]; see Section 4.5.3 of that document for encoding details. 3.2. Data Type Semantics This section describes the set of valid data type semantics of the IPFIX information model. A subregistry of data type semantics [IANA-IPFIX] 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" subregistry [IANA-IPFIX] require a Standards Action [RFC5226]. 3.2.1. quantity "quantity" is 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 "totalCounter" is 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 the Simple Network Management Protocol (SNMP), such as Counter32 as 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 "deltaCounter" is 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 as defined in [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 "identifier" is 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 "flags" is an integral value that represents a set of bit fields. Logical operations are appropriate on such values, but other mathematical operations are not. Flags MUST always be of an unsigned data type. 4. Information Element Identifiers All Information Elements defined in the IANA "IPFIX Information Elements" registry [IANA-IPFIX] have their identifiers assigned by IANA. The values of these identifiers are 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] for historical reasons. In general, IANA will add newly registered Information Elements to the registry, assigning the lowest available Information Element identifier in the range of 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 are to be registered as SMI network management private enterprise code numbers with IANA. The registry can be found at [IANA-PEN]. 5. Information Elements [IANA-IPFIX] is now the normative reference for IPFIX Information Elements. When [RFC5102] was published, it defined, in its Section 5, the initial contents of that registry. As a historical note, Information Elements (IEs) were organized into categories in [RFC5102] according to their semantics and their applicability; these categories were not carried forward into [IANA-IPFIX] 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 fields of packets or from 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 the writing of 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. 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 where it can 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 "IP Flow Information Export (IPFIX) Entities" registry [IANA-IPFIX]. New Information Element definitions can be added to this registry subject to Expert Review [RFC5226], with additional process considerations as described in [RFC7013]; 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 "IPFIX Information Element Data Types" subregistry [IANA-IPFIX] as 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 [RFC7013]. 7. IANA Considerations As this document obsoletes [RFC5102], IANA has updated the references in the "IP Flow Information Export (IPFIX) Entities" registry [IANA-IPFIX], the "IPFIX MPLS label type" subregistry of that registry, the urn:ietf:params:xml:ns:ipfix-info XML namespace, and the urn:ietf:params:xml:schema:ipfix-info XML schema to refer to this document. However, [RFC5102] still provides a historical reference for the initial entries in the "IPFIX Information Elements" registry. Therefore, IANA has kept [RFC5102] as the requestor of those Information Elements in the "IPFIX Information Elements" registry that list [RFC5102] as their requestor and added the following explanatory note to the "IPFIX Information Elements" registry: "RFC 7012 has obsoleted RFC 5102; references to RFC 5102 in this registry remain as part of the historical record". The Information Element Specification Template (Section 2.1) requires two new columns not present in [RFC5102]. IANA has created a new Revision column in the "IPFIX Information Elements" registry and set the Revision of existing Information Elements to 0. IANA has also created a new Date column in that registry and set the Date of all existing Information Elements to the publication date of this document. To identify Information Elements with identifiers 127 or below as NetFlow version 9 [RFC3954] compatible, IANA has set the Name of all existing Reserved Information Elements with identifier 127 or less to "Assigned for NetFlow v9 compatibility" and the Reference of those Information Elements to [RFC3954]. As IANA now has change control of the schema used for the IANA "IPFIX Information Elements" registry [IANA-IPFIX], IANA has deprecated the previous XML schema for the description of Information Elements urn:ietf:params:xml:schema:ipfix-info [IPFIX-XML-SCHEMA]. To support the process described in Section 7.4, IANA has established a mailing list for communicating with the IE-DOCTORS, named ie-doctors@ietf.org. The remaining subsections of this section contain no actions for IANA. 7.1. IPFIX Information Elements This document refers to Information Elements, for which the Internet Assigned Numbers Authority (IANA) has created the IPFIX "Information Elements" registry [IANA-IPFIX]. The columns of this registry must, at minimum, be able to store the information defined in the template detailed in Section 2.1; it may contain other information as necessary for the management of the registry. The process for making additions or other changes to the "IPFIX Information Elements" registry is given in Section 7.4. 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 the 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. 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. 7.3. XML Namespace and Schema The prior version of this document [RFC5102] specified an XML schema for IPFIX Information Element definitions [IPFIX-XML-SCHEMA] that was used in the generation of the document text itself. When the IANA "IPFIX Information Elements" registry [IANA-IPFIX] was created, change control on the registry and the schema used to validate it passed to IANA. The use of a machine-readable syntax for the registry enables the creation of IPFIX tools that can automatically adapt to extensions to the information model. 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. IPFIX Collectors MAY take advantage of the machine-readability of the information model versus hard-coding their behavior or inventing proprietary means for accommodating extensions. However, in order to avoid unnecessary load on the IANA infrastructure serving the registry, Collectors SHOULD NOT poll the IANA registry [IANA-IPFIX] directly at runtime. The reference to the current schema is embedded in the registry [IANA-IPFIX]; this schema may change from time to time as necessary to support the maintenance of the registry. As such, the schema urn:ietf:params:xml:schema:ipfix-info [IPFIX-XML-SCHEMA] specified in [RFC5102] has been deprecated. 7.4. Addition, Revision, and Deprecation New assignments for the "IPFIX Information Elements" registry are administered by IANA through Expert Review [RFC5226]. These experts are referred to as IE-DOCTORS and are appointed by the IESG. The process they follow is defined in [RFC7013]. Information Element identifiers in the range of 1-127 are compatible with field types used by NetFlow version 9 [RFC3954] for historical reasons and must not be assigned unless the Information Element is compatible with the NetFlow version 9 protocol, as determined by one of the IE-DOCTORS designated by the IESG as a NetFlow version 9 expert. Future assignments added to the "IPFIX Information Elements" registry that require subregistries for enumerated values (e.g., Section 7.2) 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 "IPFIX Information Elements" registry as a whole. 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 for review. When IANA receives an approval for a request to add an Information Element definition from the IE-DOCTORS, 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, 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, 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. For example, exporting values of header fields may make attacks possible for the receiver of this information; this 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. These protocols are defined in separate documents, specifically the IPFIX protocol document [RFC7011]. 9. Acknowledgments This document is substantially based on [RFC5102]. The editors thank the authors of that document; those authors are listed below as contributors. Special thanks go to Paul Aitken for the detailed review. Finally, the authors thank the IPFIX WG chairs: Nevil Brownlee and Juergen Quittek. 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. [RFC6313] Claise, B., Dhandapani, G., Aitken, P., and S. Yates, "Export of Structured Data in IP Flow Information Export (IPFIX)", RFC 6313, July 2011. [RFC7011] Claise, B., Ed., Trammell, B., Ed., and P. Aitken, "Specification of the IP Flow Information Export (IPFIX) Protocol for the Exchange of Flow Information", STD 77, RFC 7011, September 2013. [RFC7013] Trammell, B., and B. Claise, "Guidelines for Authors and Reviewers of IP Flow Information Export (IPFIX) Information Elements", BCP 184, RFC 7013, September 2013. 10.2. Informative References [IANA-IPFIX] IANA, "IP Flow Information Export (IPFIX) Entities", <http://www.iana.org/assignments/ipfix/>. [IEEE.754.2008] Institute of Electrical and Electronics Engineers, "IEEE Standard for Floating-Point Arithmetic", IEEE Standard 754, August 2008. [IEEE.802-3.2012] Institute of Electrical and Electronics Engineers, "IEEE Standard for Ethernet", IEEE Standard 802.3, 2012. [IPFIX-MED-PROTO] Claise, B., Kobayashi, A., and B. Trammell, "Operation of the IP Flow Information Export (IPFIX) Protocol on IPFIX Mediators", Work in Progress, July 2013. [IPFIX-XML-SCHEMA] IANA, "IETF XML Registry", <http://www.iana.org/assignments/xml-registry/>. [ISO.10646] International Organization for Standardization, "Information technology - Universal Coded Character Set (UCS)", ISO/IEC 10646:2012, November 2012. [IANA-PEN] IANA, "Private Enterprise Numbers", <http://www.iana.org/assignments/enterprise-numbers>. [RFC20] Cerf, V., "ASCII format for Network Interchange", RFC 20, October 1969. [RFC2578] McCloghrie, K., Ed., Perkins, D., Ed., and J. Schoenwaelder, Ed., "Structure of Management Information Version 2 (SMIv2)", STD 58, RFC 2578, April 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. [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., Ed., "Specification of the IP Flow Information Export (IPFIX) Protocol for the Exchange of IP Traffic Flow Information", RFC 5101, January 2008. [RFC5102] Quittek, J., Bryant, S., Claise, B., Aitken, P., and J. Meyer, "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., Stiemerling, M., and P. Aitken, "IP Flow Information Export (IPFIX) Implementation Guidelines", RFC 5153, 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", RFC 5470, March 2009. [RFC5471] Schmoll, C., Aitken, P., and B. Claise, "Guidelines for IP Flow Information Export (IPFIX) Testing", RFC 5471, March 2009. [RFC5472] Zseby, T., Boschi, E., Brownlee, N., and B. Claise, "IP Flow Information Export (IPFIX) Applicability", RFC 5472, March 2009. [RFC5473] Boschi, E., Mark, L., and B. Claise, "Reducing Redundancy in IP Flow Information Export (IPFIX) and Packet Sampling (PSAMP) Reports", RFC 5473, March 2009. [RFC5610] Boschi, E., Trammell, B., Mark, L., and T. Zseby, "Exporting Type Information for IP Flow Information Export (IPFIX) Information Elements", RFC 5610, July 2009. [RFC6183] Kobayashi, A., Claise, B., Muenz, G., and K. Ishibashi, "IP Flow Information Export (IPFIX) Mediation: Framework", RFC 6183, April 2011. [RFC6615] Dietz, T., Ed., Kobayashi, A., Claise, B., and G. Muenz, "Definitions of Managed Objects for IP Flow Information Export", RFC 6615, June 2012. [RFC6728] Muenz, G., Claise, B., and P. Aitken, "Configuration Data Model for the IP Flow Information Export (IPFIX) and Packet Sampling (PSAMP) Protocols", RFC 6728, October 2012. Contributors 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. 10 New Square, Bedfont Lakes Feltham, Middlesex TW18 8HA United Kingdom EMail: stbryant@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 Authors' Addresses Benoit Claise (editor) Cisco Systems, Inc. De Kleetlaan 6a b1 1831 Diegem Belgium Phone: +32 2 704 5622 EMail: bclaise@cisco.com Brian Trammell (editor) Swiss Federal Institute of Technology Zurich Gloriastrasse 35 8092 Zurich Switzerland Phone: +41 44 632 70 13 EMail: trammell@tik.ee.ethz.ch