[Docs] [txt|pdf] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits] [IPR]

Versions: (draft-li-opsawg-ipfix-bgp-community) 00 01 02 03 04 05 06 07 08 09 10 11 12

opsawg                                                             Z. Li
Internet-Draft                                                     R. Gu
Updates: 7012 (if approved)                                 China Mobile
Intended status: Standards Track                                 J. Dong
Expires: September 6, 2018                           Huawei Technologies
                                                           March 5, 2018


 Export BGP community information in IP Flow Information Export (IPFIX)
                draft-ietf-opsawg-ipfix-bgp-community-05

Abstract

   This draft updates RFC7012 IPFIX information model by introducing
   several information elements (IEs) to enable IPFIX to export the BGP
   community information, including BGP standard community defined in
   RFC1997, BGP extended community defined in RFC4360, and BGP large
   community defined in RFC8092.  Network traffic flow information can
   then be accumulated and analysed at the granularity specified by the
   BGP communities, which is suitable for and needed by some traffic
   optimization applications located in IPFIX collector, SDN controller
   or PCE (Path Computation Element).

   To clarify, no new BGP community attribute is defined in this
   document and this document has no purpose to replace BGP Monitoring
   Protocol BMP defined in RFC7854.  The IEs introduced in this document
   are used by IPFIX together with other IEs to facilitate the IPFIX
   collector analyzing the traffic in BGP community granularity without
   running the heavy BGP protocol.

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 https://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 September 6, 2018.





Li, et al.              Expires September 6, 2018               [Page 1]


Internet-Draft        Export BGP Community in IPFIX           March 2018


Copyright Notice

   Copyright (c) 2018 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
   (https://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
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   5
   3.  BGP Community based Traffic Collection  . . . . . . . . . . .   5
   4.  IEs for BGP Standard Community  . . . . . . . . . . . . . . .   6
     4.1.  bgpCommunity  . . . . . . . . . . . . . . . . . . . . . .   7
     4.2.  bgpSourceCommunityList  . . . . . . . . . . . . . . . . .   7
     4.3.  bgpDestinationCommunityList . . . . . . . . . . . . . . .   7
   5.  IEs for BGP Extended Community  . . . . . . . . . . . . . . .   8
     5.1.  bgpExtendedCommunity  . . . . . . . . . . . . . . . . . .   8
     5.2.  bgpSourceExtendedCommunityList  . . . . . . . . . . . . .   9
     5.3.  bgpDestinationExtendedCommunityList . . . . . . . . . . .   9
   6.  IEs for BGP Large Community . . . . . . . . . . . . . . . . .  10
     6.1.  bgpLargeCommunity . . . . . . . . . . . . . . . . . . . .  10
     6.2.  bgpSourceLargeCommunityList . . . . . . . . . . . . . . .  11
     6.3.  bgpDestinationLargeCommunityList  . . . . . . . . . . . .  11
   7.  Operational Considerations  . . . . . . . . . . . . . . . . .  12
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  13
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  13
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  15
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  15
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  15
     11.2.  Informative References . . . . . . . . . . . . . . . . .  16
   Appendix A.  Encoding Example . . . . . . . . . . . . . . . . . .  17
     A.1.  Template Record . . . . . . . . . . . . . . . . . . . . .  18
     A.2.  Data Set  . . . . . . . . . . . . . . . . . . . . . . . .  18
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  20








Li, et al.              Expires September 6, 2018               [Page 2]


Internet-Draft        Export BGP Community in IPFIX           March 2018


1.  Introduction

   IP Flow Information Export (IPFIX) [RFC7011] provides network
   administrators with traffic flow information using the information
   elements (IEs) defined in [IANA-IPFIX] registries.  Based on the
   traffic flow information, network administrators know the amount and
   direction of the traffic in their network, then they can optimize
   their network when needed.  For example, they can shift some flows
   from the congested links to the low utilized links through a SDN
   controller or PCE [RFC4655].

   [IANA-IPFIX] has already defined the following IEs for traffic flow
   information exporting in different granularities: sourceIPv4Address,
   sourceIPv4Prefix, destinationIPv4Address, destinationIPv4Prefix,
   bgpSourceAsNumber, bgpDestinationAsNumber, bgpNextHopIPv4Address,
   etc.  In some circumstances, however, especially when traffic
   engineering and optimization are executed in the Tier 1 or Tier 2
   operators' backbone networks, traffic flow information based on these
   IEs may not be suitable.  Flow information based on IP address or IP
   prefix may provide much too fine granularity for a large network.  On
   the contrary, flow information based on AS number may be too coarse.

   BGP community is a BGP path attribute defined in IDR (Inter Domain
   Routing) working group.  The already defined BGP community attribute
   includes the standard community defined in [RFC1997], the extended
   community defined in [RFC4360], and the large community defined in
   [RFC8092].  BGP community attribute has a variety of use cases, one
   common practice of which for the operators is to use BGP community
   with planned specific values in their field networks to represent the
   groups of customers, peers, geographical and topological regions.
   Please refer to [RFC4384], [RFC8195] and Section 3 of this document
   for the detailed examples.  To know the traffic generated by differnt
   kinds of customers, from differnt geographical or topological
   regions, by differnt kinds of customers in differnt regions, we need
   the corresponding community information related to the traffic flow
   exported by IPFIX.  Netwok traffic statistic in BGP community
   granularity is useful not only for the traffic analyzing, but also
   can then be used by other applications, such as the traffic
   optimization applications located in IPFIX collector, SDN controller
   or PCE.  [Community-TE] also states analyzing network traffic
   information at the granularity specified by BGP community is prefered
   for inbound traffic engineering.  However, there is no IE defined for
   BGP community attribute in [IANA-IPFIX] yet.

   Flow information based on BGP community may be collected by a
   mediator defined in [RFC6183].  Mediator is responsible for the
   correlation between flow information and BGP community.  However no
   IEs are defined in [RFC6183] for exporting BGP community information



Li, et al.              Expires September 6, 2018               [Page 3]


Internet-Draft        Export BGP Community in IPFIX           March 2018


   in IPFIX.  Furthermore, to correlate the BGP community with the flow
   information, mediator needs to learn BGP routes and perform lookup in
   the BGP routing table to get the matching entry for a specific flow.
   Neither BGP route learning nor routing table lookup is trivial for a
   mediator.  Mediator is mainly introduced to release the performance
   requirement for the exporter [RFC5982].  In fact, to obtain the
   information for BGP related IEs that have already been defined, such
   as bgpSourceAsNumber, bgpDestinationAsNumber, and
   bgpNextHopIPv4Address, etc, exporter has to hold the up-to-date BGP
   routing table and perform lookup in the BGP routing table.  The
   exporter can obtain the BGP community information in the same
   procedure, thus exporting BGP community information adds no more
   requirement for exporter.  It is RECOMMENDED that the BGP community
   information be exported by the exporter directly using IPFIX.

   Through running BGP [RFC4271] or BMP [RFC7854] and performing lookup
   in the BGP routing table to get the matching entry for a specific
   flow (we call it correlation), IPFIX collectors and other
   applications, such as SDN controller or PCE, can figure up the
   network traffic at BGP community granularity.  However,neither
   running BGP or BMP protocol nor routing table lookup is trivial for
   the IPFIX collectors and other applications.  Moreover correlation
   between IPFIX flow information and the BGP RIB on the exporter (such
   as router) is more accurate, compared to the correlation on a
   collector, since the BGP routing table may be updated when the IPFIX
   collectors and other applications reveive the IPFIX flow information.
   And as stated above, the exporter can obtain the BGP community
   information in the same procedure when it obtains other BGP related
   informaiton.  So exporting the BGP community information directly by
   the exporter to the collector is the efficient and accurate way.  If
   the IPFIX collectors and other applications only want to figure up
   the network traffic at BGP community granularity, they do not need to
   run the heavy BGP or BMP protocol when the BGP community information
   can be obtained by IPFIX.  However, we have to clarify, the BMP
   protocol has its own application scenario, the mechanisum introduced
   in this document has no purpose to replace it.

   This draft introduces new IEs to extend the IPFIX information model
   defined in [RFC7012] to export the BGP community information,
   including BGP standard community defined in [RFC1997], BGP extended
   community defined in [RFC4360], and BGP large community defined in
   [RFC8092].  Flow information, including packetDeltaCount,
   octetDeltaCount [RFC7012] etc, can then be accumulated and analysed
   by the collector or other applications, such as SDN controller or PCE
   [RFC4655], at the granularity specified by BGP community , which is
   useful for knowing the traffic generted by different kinds of
   customers, from differnt geographical or topological regions
   according to the operator's BGP community plan, and can then be used



Li, et al.              Expires September 6, 2018               [Page 4]


Internet-Draft        Export BGP Community in IPFIX           March 2018


   by the traffic engineering or traffic optimization applications,
   especially in the backbone network.  To clarify, no new BGP community
   attribute is defined in this document, IDR (Inter Domain Routing)
   working group is the right place to define new community attributes
   for the BGP protocol.

   The IEs introduced in this document are applicable for both IPv4 and
   IPv6 traffic.  Both exporter and mediator can use these IEs to export
   BGP community information in IPFIX.

   Please refer Appendix A for the encoding example and Section 3 for a
   detailed use case.

2.  Terminology

   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].

3.  BGP Community based Traffic Collection

   [RFC4384] introduces the mechanism of using BGP standard communities
   and extended communities to collect the geographical and topological
   related information in BGP routing system.  [RFC8195] gives some
   examples about the application of BGP large communities to represent
   the geographical regions.  Since the network traffic at the BGP
   community granularity represents the traffic generted by different
   kinds of customers, from differnt geographical regions according to
   the network operator's BGP community plan, it is useful for the
   network operators to analyze and optimize the network traffic among
   different customers and regions.  This section gives a use case in
   which the network operator uses the BGP community based traffic
   information to adjust the network paths for different traffic flows.

   Considering the following scenario, AS C provides transit connection
   between AS A and B.  By tagging with different BGP communities, the
   routes of AS A and B are categorized into several groups respectively
   with the operator's plan.  For example community A:X and A:Y are used
   for the routes originated from different geographical regions in AS
   A, and community B:M and B:N are used for the routes representing the
   different kinds of customers in AS B, such as B:M is for the mobile
   customers and B:N is for the fixed line customers.  By default, all
   traffic originated from AS A and destinated to AS B (we call it
   traffic A-B) goes through path C1-C2-C3 (call it Path-1) in AS C.
   When the link between C1 and C2 is congested, we cannot simply steer
   all the traffic A-B from Path-1 to Path C1-C4-C3 (call it Path-2),
   becuse it will cause the congestion in Path-2.




Li, et al.              Expires September 6, 2018               [Page 5]


Internet-Draft        Export BGP Community in IPFIX           March 2018


                                +----------+
                                | PCE/SDN  |
                        +-------|Controller|-------+
                        |       +----------+       |
                        |                          |
                        |           AS C           |
                |       |       +----------+       |       |
                |       |   +---|Router C2 |---+   |       |
                |       |   |   +----------+   |   |       |
       AS A     |       |   |100             50|   |       |     AS B
    +--------+  |  +---------+                +---------+  |  +--------+
    |Router A|--|--|Router C1|                |Router C3|--|--|Router B|
    +--------+  |  +---------+                +---------+  |  +--------+
    Community:  |           |100            100|           |  Community:
        A:X     |           |   +----------+   |           |     B:M
        A:Y     |           +---|Router C4 |---+           |     B:N
                                +----------+

             Figure 1: BGP Community based Traffic Collection

   If the PCE/SDN controller in AS C can obtain the network traffic
   information at BGP community granularity, it can steer some traffic
   related to some BGP communities (when we consider only the source or
   destination of the traffic), or some BGP community pairs (when we
   consider both the source and the destination of the traffic) from
   Path-1 to Path-2 according to the utilization of different paths.
   For instance, steer the traffic generated by community A:X from
   Path-1 to Path-2 by deploying route policy at Router C1, or steer the
   traffic from community A:Y to community B:M from Path-1 to Path-2.
   Using the IEs defined in this document, IPFIX can export the BGP
   community information related to a specific traffic flow togecher
   with other flow information.  The traffic information can then be
   accumulated at BGP community granularity and used by the PCE/SDN
   controller to steer the appropriate traffic from Path-1 to Path-2.

4.  IEs for BGP Standard Community

   [RFC1997] defines the BGP Communities attribute, called BGP Standard
   Community in this document, which describes a group of routes sharing
   some common properties.  BGP Standard Communities are treated as 32
   bit values as stated in[RFC1997].

   In order to export BGP standard community information along with
   other flow information defined by IPFIX, three new IEs are
   introduced.  One is bgpCommunity, which is used to identify that the
   value in this IE is a BGP standard community.  The other two are
   bgpSourceCommunityList and bgpDestinationCommunityList, which are
   both basicList [RFC6313] of bgpCommunity, and are used to export BGP



Li, et al.              Expires September 6, 2018               [Page 6]


Internet-Draft        Export BGP Community in IPFIX           March 2018


   standard community information corresponding to a specific flow's
   source IP and destination IP respectively.

   The detailed information of the three new IEs are shown in the
   following sections.

4.1.  bgpCommunity

  ----------------------------------------------------------------------
  |      ElementID      |            to be assigned by IANA            |
  |--------------------------------------------------------------------|
  |         Name        |                 bgpCommunity                 |
  |--------------------------------------------------------------------|
  |      Data Type      |                  unsigned32                  |
  |--------------------------------------------------------------------|
  | Data Type Semantics |                  identifier                  |
  |--------------------------------------------------------------------|
  |      Description    |    BGP community as defined in [RFC1997]     |
  |--------------------------------------------------------------------|
  |         Units       |                     none                     |
  |--------------------------------------------------------------------|

                          Figure 2: bgpCommunity

4.2.  bgpSourceCommunityList

  ----------------------------------------------------------------------
  |      ElementID      |           to be assigned by IANA             |
  |--------------------------------------------------------------------|
  |         Name        |           bgpSourceCommunityList             |
  |--------------------------------------------------------------------|
  |      Data Type      |      basicList, as specified in [RFC6313]    |
  |--------------------------------------------------------------------|
  | Data Type Semantics |                       list                   |
  |--------------------------------------------------------------------|
  |      Description    | zero or more BGP communities corresponding   |
  |                     | with source IP address of a specific flow    |
  |--------------------------------------------------------------------|
  |         Units       |                     none                     |
  |--------------------------------------------------------------------|

                     Figure 3: bgpSourceCommunityList

4.3.  bgpDestinationCommunityList







Li, et al.              Expires September 6, 2018               [Page 7]


Internet-Draft        Export BGP Community in IPFIX           March 2018


  ---------------------------------------------------------------------
  |      ElementID      |             to be assigned by IANA           |
  |--------------------------------------------------------------------|
  |         Name        |          bgpDestinationCommunityList         |
  |--------------------------------------------------------------------|
  |      Data Type      |      basicList, as specified in [RFC6313]    |
  |--------------------------------------------------------------------|
  | Data Type Semantics |                       list                   |
  |--------------------------------------------------------------------|
  |      Description    | zero or more BGP communities corresponding   |
  |                     |with destination IP address of a specific flow|
  |--------------------------------------------------------------------|
  |         Units       |                     none                     |
  |--------------------------------------------------------------------|

                   Figure 4: bgpDestinationCommunityList

5.  IEs for BGP Extended Community

   [RFC4360] defines the BGP Extended Communities attribute, which
   provides a mechanism for labeling the information carried in BGP.
   Each Extended Community is encoded as an 8-octet quantity with the
   format defined in [RFC4360].

   In order to export BGP Extended Community information together with
   other flow information by IPFIX, three new IEs are introduced.  The
   first one is bgpExtendedCommunity, which is used to identify that the
   value in this IE is a BGP Extended Community.  The other two are
   bgpSourceExtendedCommunityList and
   bgpDestinationExtendedCommunityList, which are both basicList
   [RFC6313] of bgpExtendedCommunity, and are used to export the BGP
   Extended Community information corresponding to a specific flow's
   source IP and destination IP respectively.

   The detailed information of the three new IEs are shown in the
   following sections.

5.1.  bgpExtendedCommunity













Li, et al.              Expires September 6, 2018               [Page 8]


Internet-Draft        Export BGP Community in IPFIX           March 2018


  ----------------------------------------------------------------------
  |      ElementID      |            to be assigned by IANA            |
  |--------------------------------------------------------------------|
  |         Name        |              bgpExtendedCommunity            |
  |--------------------------------------------------------------------|
  |      Data Type      |                  octetArray                  |
  |--------------------------------------------------------------------|
  | Data Type Semantics |                    default                   |
  |--------------------------------------------------------------------|
  |                     |BGP Extended Community as defined in [RFC4360]|
  |      Description    |The size of this Information Element is 8     |
  |                     |octets.                                       |
  |--------------------------------------------------------------------|
  |         Units       |                     none                     |
  |--------------------------------------------------------------------|


                      Figure 5: bgpExtendedCommunity

5.2.  bgpSourceExtendedCommunityList

  ----------------------------------------------------------------------
  |      ElementID      |           to be assigned by IANA             |
  |--------------------------------------------------------------------|
  |         Name        |        bgpSourceExtendedCommunityList        |
  |--------------------------------------------------------------------|
  |      Data Type      |      basicList, as specified in [RFC6313]    |
  |--------------------------------------------------------------------|
  | Data Type Semantics |                       list                   |
  |--------------------------------------------------------------------|
  |                     |    zero or more BGP Extended Communities     |
  |      Description    |     corresponding with source IP address     |
  |                     |             of a specific flow               |
  |--------------------------------------------------------------------|
  |         Units       |                     none                     |
  |--------------------------------------------------------------------|


                 Figure 6: bgpSourceExtendedCommunityList

5.3.  bgpDestinationExtendedCommunityList










Li, et al.              Expires September 6, 2018               [Page 9]


Internet-Draft        Export BGP Community in IPFIX           March 2018


  ----------------------------------------------------------------------
  |      ElementID      |             to be assigned by IANA           |
  |--------------------------------------------------------------------|
  |         Name        |       bgpDestinationExtendedCommunityList    |
  |--------------------------------------------------------------------|
  |      Data Type      |      basicList, as specified in [RFC6313]    |
  |--------------------------------------------------------------------|
  | Data Type Semantics |                       list                   |
  |--------------------------------------------------------------------|
  |                     |     zero or more BGP Extended communities    |
  |      Description    |   corresponding with destination IP address  |
  |                     |              of a specific flow              |
  |--------------------------------------------------------------------|
  |         Units       |                     none                     |
  |--------------------------------------------------------------------|


               Figure 7: bgpDestinationExtendedCommunityList

6.  IEs for BGP Large Community

   [RFC8092] defines the BGP Large Communities attribute, which is
   suitable for use with all Autonomous System Numbers (ASNs) including
   four-octet ASNs.  Each BGP Large Community is encoded as a 12-octet
   quantity with the format defined in [RFC8092].

   In order to export BGP Large Community information together with
   other flow information by IPFIX, three new IEs are introduced.  The
   first one is bgpLargeCommunity, which is used to identify that the
   value in this IE is a BGP Large Community.  The other two are
   bgpSourceLargeCommunityList and bgpDestinationLargeCommunityList,
   which are both basicList [RFC6313] of bgpLargeCommunity, and are used
   to export the BGP Large Community information corresponding to a
   specific flow's source IP and destination IP respectively.

   The detailed information of the three new IEs are shown in the
   following sections.

6.1.  bgpLargeCommunity












Li, et al.              Expires September 6, 2018              [Page 10]


Internet-Draft        Export BGP Community in IPFIX           March 2018


  ----------------------------------------------------------------------
  |      ElementID      |            to be assigned by IANA            |
  |--------------------------------------------------------------------|
  |         Name        |                 bgpLargeCommunity            |
  |--------------------------------------------------------------------|
  |      Data Type      |                  octetArray                  |
  |--------------------------------------------------------------------|
  | Data Type Semantics |                    default                   |
  |--------------------------------------------------------------------|
  |                     | BGP Large Community as defined in [RFC8092]  |
  |      Description    | The size of this Information Element is 12   |
  |                     | octets.                                      |
  |--------------------------------------------------------------------|
  |         Units       |                     none                     |
  |---------------------------------------------------------------------


                        Figure 8: bgpLargeCommunity

6.2.  bgpSourceLargeCommunityList

  ----------------------------------------------------------------------
  |      ElementID      |           to be assigned by IANA             |
  |--------------------------------------------------------------------|
  |         Name        |        bgpSourceLargeCommunityList           |
  |--------------------------------------------------------------------|
  |      Data Type      |      basicList, as specified in [RFC6313]    |
  |--------------------------------------------------------------------|
  | Data Type Semantics |                       list                   |
  |--------------------------------------------------------------------|
  |                     |     zero or more BGP Large Communities       |
  |       Description   |    corresponding with source IP address      |
  |                     |             of a specific flow               |
  |--------------------------------------------------------------------|
  |         Units       |                     none                     |
  |--------------------------------------------------------------------|


                   Figure 9: bgpSourceLargeCommunityList

6.3.  bgpDestinationLargeCommunityList










Li, et al.              Expires September 6, 2018              [Page 11]


Internet-Draft        Export BGP Community in IPFIX           March 2018


  ----------------------------------------------------------------------
  |      ElementID      |             to be assigned by IANA           |
  |--------------------------------------------------------------------|
  |         Name        |       bgpDestinationLargeCommunityList       |
  |--------------------------------------------------------------------|
  |      Data Type      |      basicList, as specified in [RFC6313]    |
  |--------------------------------------------------------------------|
  | Data Type Semantics |                       list                   |
  |--------------------------------------------------------------------|
  |      Description    |     zero or more BGP Large communities       |
  |                     |   corresponding with destination IP address  |
  |                     |              of a specific flow              |
  |--------------------------------------------------------------------|
  |         Units       |                     none                     |
  |--------------------------------------------------------------------|


                Figure 10: bgpDestinationLargeCommunityList

7.  Operational Considerations

   The maximum length of an IPFIX message is 65535 bytes as per
   [RFC7011] , and the maximum length of a normal BGP message is 4096
   bytes as per [RFC4271].  Since BGP communities, including standard,
   extended, and large communities , are BGP path attributes carried in
   BGP Update messages, the total length of these attributes can not
   exceed the length of a BGP message, i.e. 4096 bytes.  So one IPFIX
   message with maximum length of 65535 bytes has enough space to fit
   all the communities related to a specific flow, both the source IP
   and the destination IP related.

   [I-D.ietf-idr-bgp-extended-messages] extends the maximum size of a
   BGP Update message to 65535 bytes.  Then theoretically the BGP
   community information related to a specific flow may exceed the
   length one IPFIX message.  However, according to the information
   about the networks in the field, the number of BGP communities in one
   BGP route is usually no more than 10.  Nevertheless, BGP speakers
   that support the extended message SHOULD be careful to export the BGP
   communities in the IPFIX message properly, such as only convey as
   many communities as possible in the IPFIX message.  The collector
   which receives an IPFIX message with maximum length and BGP
   communities contained in its data set SHOULD be aware that the BGP
   communities may be truncated due to limited message space.  In this
   case, it is RECOMMENDED to configure export policy of BGP communities
   on the exporter to limit the BGP communities to be exported, so as to
   only export some specific communities,or not to export some specific
   communities.




Li, et al.              Expires September 6, 2018              [Page 12]


Internet-Draft        Export BGP Community in IPFIX           March 2018


   If needed, we may consider to extend the message length of IPFIX
   [RFC7011] from 16 bits to 32 bits to solve this problem completely.
   The detailed mechanism is out of the scope of this document.

   To align with the size of BGP extended community and large community,
   the size of IE bgpExtendedCommunity and bgpLargeCommunity is 8 octets
   and 12 octets respectively.  In the event that the
   bgpExtendedCommunity or bgpLargeCommunity Elements are not of their
   expected sizes (8 and 12 octets, respectively), the IPFIX collector
   SHOULD ignore them.  This is intended to protect implementations
   using BGP logic from calling their parsing routines with invalid
   lengths.

   For the proper processing of the exporter, when it receives the
   template requesting to report the BGP community information (refer
   Appendix A for an example), the exporter SHOULD obtain the
   coressponding BGP community information through BGP lookup using the
   corresponding source or destination IP of the specific traffic flow.
   When exporting the IPFIX information to the collector, the exporter
   SHOULD include the corresponding BGP communities in the IPFIX
   message.

8.  Security Considerations

   This document only defines three new IEs for IPFIX.  This document
   itself does not directly introduce security issues.  The same
   security considerations as for the IPFIX Protocol Specification
   [RFC7011] and Information Model [RFC7012] apply.

   As the BGP community information is deducible by other means, there
   are no increased privacy concerns, neither.

9.  IANA Considerations

   This draft specifies the following IPFIX IEs to export BGP community
   information along with other flow information.

   The Element IDs for these IEs are solicited to be assigned by IANA.
   The following table is for IANA's reference to put in each field in
   the registry.

  ----------------------------------------------------------------------
  |ElementID|            Name           | Data Type|Data Type Semantics|
  |--------------------------------------------------------------------|
  |   TBA1  |        bgpCommunity       |unsigned32|     identifier    |
  |--------------------------------------------------------------------|
  |   TBA2  |  bgpSourceCommunityList   | basicList|        list       |
  |--------------------------------------------------------------------|



Li, et al.              Expires September 6, 2018              [Page 13]


Internet-Draft        Export BGP Community in IPFIX           March 2018


  |   TBA3  |bgpDestinationCommunityList| basicList|        list       |
  |--------------------------------------------------------------------|
  |   TBA4  |     bgpExtendedCommunity  |octetArray|       default     |
  |--------------------------------------------------------------------|
  |   TBA5  |      bgpSourceExtended    |          |                   |
  |         |        CommunityList      | basicList|        list       |
  |--------------------------------------------------------------------|
  |   TBA6  |  bgpDestinationExtended   |          |                   |
  |         |       CommunityList       | basicList|        list       |
  |--------------------------------------------------------------------|
  |   TBA7  |     bgpLargeCommunity     |octetArray|       default     |
  |--------------------------------------------------------------------|
  |   TBA8  |bgpSourceLargeCommunityList| basicList|        list       |
  |--------------------------------------------------------------------|
  |   TBA9  |    bgpDestinationLarge    |          |                   |
  |         |       CommunityList       | basicList|        list       |
  |--------------------------------------------------------------------|

  ----------------------------------------------------------------------
  |ElementID|                 Description                  |   Units   |
  |--------------------------------------------------------------------|
  |   TBA1  |    BGP community as defined in [RFC1997]     |           |
  |--------------------------------------------------------------------|
  |   TBA2  |  zero or more BGP communities corresponding  |           |
  |         |  with source IP address of a specific flow   |           |
  |--------------------------------------------------------------------|
  |   TBA3  |  zero or more BGP communities corresponding  |           |
  |         |with destination IP address of a specific flow|           |
  |--------------------------------------------------------------------|
  |   TBA4  |BGP Extended Community as defined in [RFC4360]|           |
  |         |The size of this IE is 8 octets               |           |
  |--------------------------------------------------------------------|
  |         |    zero or more BGP Extended Communities     |           |
  |   TBA5  | corresponding with source IP address of      |           |
  |         |               a specific flow                |           |
  |--------------------------------------------------------------------|
  |         |    zero or more BGP Extended communities     |           |
  |   TBA6  |  corresponding with destination IP address   |           |
  |         |              of a specific flow              |           |
  |--------------------------------------------------------------------|
  |   TBA7  | BGP Large Community as defined in [RFC8092]  |           |
  |         | The size of this IE is 12 octets.            |           |
  |--------------------------------------------------------------------|
  |         |     zero or more BGP Large Communities       |           |
  |   TBA8  |    corresponding with source IP address      |           |
  |         |             of a specific flow               |           |
  |--------------------------------------------------------------------|
  |         |     zero or more BGP Large communities       |           |



Li, et al.              Expires September 6, 2018              [Page 14]


Internet-Draft        Export BGP Community in IPFIX           March 2018


  |   TBA9  |   corresponding with destination IP address  |           |
  |         |              of a specific flow              |           |
  |--------------------------------------------------------------------|

  ----------------------------------------------------------------------
  |ElementID|  Range  |   References  | Requester | Revision |   date  |
  |--------------------------------------------------------------------|
  |   TBA1  |         |    RFC1997    |this draft |    0     |         |
  |--------------------------------------------------------------------|
  |   TBA2  |         |RFC6313,RFC1997|this draft |    0     |         |
  |--------------------------------------------------------------------|
  |   TBA3  |         |RFC6313,RFC1997|this draft |    0     |         |
  |--------------------------------------------------------------------|
  |   TBA4  |         |    RFC4360    |this draft |    0     |         |
  |--------------------------------------------------------------------|
  |   TBA5  |         |RFC6313,RFC4360|this draft |    0     |         |
  |--------------------------------------------------------------------|
  |   TBA6  |         |RFC6313,RFC4360|this draft |    0     |         |
  |--------------------------------------------------------------------|
  |   TBA7  |         |    RFC8092    |this draft |    0     |         |
  |--------------------------------------------------------------------|
  |   TBA8  |         |RFC6313,RFC8092|this draft |    0     |         |
  |--------------------------------------------------------------------|
  |   TBA9  |         |RFC6313,RFC8092|this draft |    0     |         |
  |--------------------------------------------------------------------|

                      Figure 11: IANA Considerations

10.  Acknowledgements

   The authors would like to thank Benoit Claise and Paul Aitken for
   their comments and suggestions to promote this document.
   Appreciations are given to Tianran Zhou, Warren Kumari, Jeffrey Haas,
   Ignas Bagdonas, Stewart Bryant, Paolo Lucente, Job Snijders, Jared
   Mauch, Rudiger Volk, etc, for their discussion, comments and
   suggestions in the face to face meetings and in the mail list.

11.  References

11.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.






Li, et al.              Expires September 6, 2018              [Page 15]


Internet-Draft        Export BGP Community in IPFIX           March 2018


   [RFC6313]  Claise, B., Dhandapani, G., Aitken, P., and S. Yates,
              "Export of Structured Data in IP Flow Information Export
              (IPFIX)", RFC 6313, DOI 10.17487/RFC6313, July 2011,
              <https://www.rfc-editor.org/info/rfc6313>.

   [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, DOI 10.17487/RFC7011, September 2013,
              <https://www.rfc-editor.org/info/rfc7011>.

   [RFC7012]  Claise, B., Ed. and B. Trammell, Ed., "Information Model
              for IP Flow Information Export (IPFIX)", RFC 7012,
              DOI 10.17487/RFC7012, September 2013,
              <https://www.rfc-editor.org/info/rfc7012>.

11.2.  Informative References

   [Community-TE]
              Shao, W., Devienne, F., Iannone, L., and JL. Rougier, "On
              the use of BGP communities for fine-grained inbound
              traffic engineering", Computer Science 27392(1):476-487,
              November 2015.

   [I-D.ietf-idr-bgp-extended-messages]
              Bush, R., Patel, K., and D. Ward, "Extended Message
              support for BGP", draft-ietf-idr-bgp-extended-messages-24
              (work in progress), November 2017.

   [IANA-IPFIX]
              "IP Flow Information Export (IPFIX) Entities",
              <http://www.iana.org/assignments/ipfix/>.

   [RFC1997]  Chandra, R., Traina, P., and T. Li, "BGP Communities
              Attribute", RFC 1997, DOI 10.17487/RFC1997, August 1996,
              <https://www.rfc-editor.org/info/rfc1997>.

   [RFC4271]  Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
              Border Gateway Protocol 4 (BGP-4)", RFC 4271,
              DOI 10.17487/RFC4271, January 2006,
              <https://www.rfc-editor.org/info/rfc4271>.

   [RFC4360]  Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
              Communities Attribute", RFC 4360, DOI 10.17487/RFC4360,
              February 2006, <https://www.rfc-editor.org/info/rfc4360>.






Li, et al.              Expires September 6, 2018              [Page 16]


Internet-Draft        Export BGP Community in IPFIX           March 2018


   [RFC4384]  Meyer, D., "BGP Communities for Data Collection", BCP 114,
              RFC 4384, DOI 10.17487/RFC4384, February 2006,
              <https://www.rfc-editor.org/info/rfc4384>.

   [RFC4655]  Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
              Element (PCE)-Based Architecture", RFC 4655,
              DOI 10.17487/RFC4655, August 2006,
              <https://www.rfc-editor.org/info/rfc4655>.

   [RFC5982]  Kobayashi, A., Ed. and B. Claise, Ed., "IP Flow
              Information Export (IPFIX) Mediation: Problem Statement",
              RFC 5982, DOI 10.17487/RFC5982, August 2010,
              <https://www.rfc-editor.org/info/rfc5982>.

   [RFC6183]  Kobayashi, A., Claise, B., Muenz, G., and K. Ishibashi,
              "IP Flow Information Export (IPFIX) Mediation: Framework",
              RFC 6183, DOI 10.17487/RFC6183, April 2011,
              <https://www.rfc-editor.org/info/rfc6183>.

   [RFC7854]  Scudder, J., Ed., Fernando, R., and S. Stuart, "BGP
              Monitoring Protocol (BMP)", RFC 7854,
              DOI 10.17487/RFC7854, June 2016,
              <https://www.rfc-editor.org/info/rfc7854>.

   [RFC8092]  Heitz, J., Ed., Snijders, J., Ed., Patel, K., Bagdonas,
              I., and N. Hilliard, "BGP Large Communities Attribute",
              RFC 8092, DOI 10.17487/RFC8092, February 2017,
              <https://www.rfc-editor.org/info/rfc8092>.

   [RFC8195]  Snijders, J., Heasley, J., and M. Schmidt, "Use of BGP
              Large Communities", RFC 8195, DOI 10.17487/RFC8195, June
              2017, <https://www.rfc-editor.org/info/rfc8195>.

Appendix A.  Encoding Example

   In this section, we give an example to show the encoding format for
   the new introduced IEs.

   Flow information including BGP communities is shown in the below
   table.  Suppose we want all the fields to be reported by IPFIX.











Li, et al.              Expires September 6, 2018              [Page 17]


Internet-Draft        Export BGP Community in IPFIX           March 2018


 -----------------------------------------------------------------------
 |Source ip|Destination ip |Source BGP community|   Destination BGP    |
 |         |               |                    |      community       |
 -----------------------------------------------------------------------
 | 1.1.1.1 |   2.2.2.2     |1:1001,1:1002,8:1001|     2:1002,8:1001    |
 -----------------------------------------------------------------------
 | 3.3.3.3 |   4.4.4.4     |3:1001,3:1002,8:1001|     4:1001,8:1001    |
 -----------------------------------------------------------------------

           Figure 12: Flow information including BGP communities

A.1.  Template Record

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |          SET ID = 2           |       Length = 24             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      Template ID = 256        |        Field Count = 4        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |0|    SourceIPv4Address = 8    |        Field length = 4       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |0| DestinationIPv4Address = 12 |        Field length = 4       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |0| bgpSourceCommunityList = 459|      Field length = 0xFFFF    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |0| bgpDestinationCommunityList |      Field length = 0xFFFF    |
   | |         = 460               |                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                Figure 13: Template Record Encoding Format

   In this example, the Template ID is 256, which will be used in the
   data record.  The field length for bgpSourceCommunityList and
   bgpDestinationCommunityList is 0xFFFF, which means the length of this
   IE is variable, the actual length of this IE is indicated by the list
   length field in the basic list format as per [RFC6313].

A.2.  Data Set

   The data set is represented as follows:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         SET ID = 256          |           Length = 92         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                  SourceIPv4Address = 1.1.1.1                  |



Li, et al.              Expires September 6, 2018              [Page 18]


Internet-Draft        Export BGP Community in IPFIX           March 2018


   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |               DestinationIPv4Address = 2.2.2.2                |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      255      |        List length = 17       |semantic=allof |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      bgpCommunity = 458       |          Field Len = 4        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        BGP Source Community Value 1 = 1:1001                  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        BGP Source Community Value 2 = 1:1002                  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        BGP Source Community Value 3 = 8:1001                  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     255       |        List length = 13       |semantic =allof|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      bgpCommunity = 458       |          Field Len = 4        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         BGP Destination Community Value 1 = 2:1002            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         BGP Destination Community Value 2 = 8:1001            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                  SourceIPv4Address = 3.3.3.3                  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |               DestinationIPv4Address = 4.4.4.4                |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     255       |        List length = 17       |semantic =allof|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      bgpCommunity = 458       |          Field Len = 4        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        BGP Source Community Value 1  = 3:1001                 |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        BGP Source Community Value 2  = 3:1002                 |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        BGP Source Community Value 3  = 8:1001                 |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     255       |        List length = 13       |semantic =allof|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      bgpCommunity = 458       |          Field Len = 4        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         BGP Destination Community Value 1 = 4:1001            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         BGP Destination Community Value 2 = 8:1001            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                    Figure 14: Data Set Encoding Format






Li, et al.              Expires September 6, 2018              [Page 19]


Internet-Draft        Export BGP Community in IPFIX           March 2018


Authors' Addresses

   Zhenqiang Li
   China Mobile
   32 Xuanwumen West Ave, Xicheng District
   Beijing  100053
   China

   Email: li_zhenqiang@hotmail.com


   Rong Gu
   China Mobile
   32 Xuanwumen West Ave, Xicheng District
   Beijing  100053
   China

   Email: gurong_cmcc@outlook.com


   Jie Dong
   Huawei Technologies
   Huawei Campus, No. 156 Beiqing Rd.
   Beijing  100095
   China

   Email: jie.dong@huawei.com
























Li, et al.              Expires September 6, 2018              [Page 20]


Html markup produced by rfcmarkup 1.129c, available from https://tools.ietf.org/tools/rfcmarkup/