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Versions: (draft-heitz-idr-large-community) 00 01 02 03 04 05 06 07 08 09 10 11 12 RFC 8092

IDR                                                        J. Heitz, Ed.
Internet-Draft                                                     Cisco
Intended status: Standards Track                        J. Snijders, Ed.
Expires: April 19, 2017                                              NTT
                                                                K. Patel
                                                                  Arrcus
                                                             I. Bagdonas
                                                                 Equinix
                                                              A. Simpson
                                                                   Nokia
                                                             N. Hilliard
                                                                    INEX
                                                        October 16, 2016


                         Large BGP Communities
                   draft-ietf-idr-large-community-03

Abstract

   This document describes the Large BGP Communities attribute, an
   extension to BGP-4.  This attribute provides a mechanism to signal
   opaque information within separate namespaces to aid in routing
   management.  The attribute is suitable for use in four-octet ASNs.

Requirements Language

   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].

Status of This Memo

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

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

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

   This Internet-Draft will expire on April 19, 2017.




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Copyright Notice

   Copyright (c) 2016 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  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Large BGP Communities Attribute . . . . . . . . . . . . . . .   3
   3.  Aggregation . . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Canonical Representation  . . . . . . . . . . . . . . . . . .   4
   5.  Reserved Large BGP Community values . . . . . . . . . . . . .   4
   6.  Error Handling  . . . . . . . . . . . . . . . . . . . . . . .   4
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   8.  Implementation status - RFC EDITOR: REMOVE BEFORE PUBLICATION   5
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   6
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     11.1.  Normative References . . . . . . . . . . . . . . . . . .   6
     11.2.  Informative References . . . . . . . . . . . . . . . . .   7
     11.3.  URIs . . . . . . . . . . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   BGP implementations typically support a routing policy language to
   control the distribution of routing information.  Network operators
   attach BGP communities to routes to identify intrinsic properties of
   these routes.  These properties may include information such as the
   route origin location, or specification of a routing policy action to
   be taken, or one that has been taken, and may apply to an individual
   route or to a group of routes.  Because BGP communities are optional
   transitive BGP attributes, BGP communities may be acted upon or
   otherwise used by routing policies in other Autonomous Systems (ASes)
   on the Internet.

   [RFC1997] BGP Communities attributes are four-octet values split into
   two two-octet words.  The most significant word is usually



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   interpreted as an Autonomous System Number (ASN) and the least
   significant word is a locally defined value whose meaning is assigned
   by the operator of the Autonomous System in the most significant
   word.

   Since the adoption of four-octet ASNs [RFC6793], the BGP Communities
   attribute can no longer accommodate the above encoding, as a two-
   octet word cannot fit a four-octet ASN.  The BGP Extended Communities
   attribute [RFC4360] is also unsuitable, as the protocol limit of six
   octets cannot accommodate both a four-octet Global Administrator
   value and a four-octet Local Administrator value, which precludes the
   common operational practice of encoding a target ASN in the Local
   Administrator field.

   To address these shortcomings, this document defines a Large BGP
   Communities attribute encoded as one or more twelve-octet values,
   each consisting of a four-octet ASN and two four-octet operator-
   defined values, each of which can be used to denote properties or
   actions significant to that ASN.

2.  Large BGP Communities Attribute

   This document creates the Large BGP Communities attribute as an
   optional transitive path attribute of variable length.  All routes
   with the Large BGP Communities attribute belong to the community
   specified in the attribute.

   The attribute consists of one or more twelve-octet values.  Each
   twelve-octet Large BGP Communities value represents three four-octet
   values, 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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Global Administrator                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Local Data Part 1                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Local Data Part 2                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Global Administrator:  A four-octet namespace identifier.  This
      SHOULD be an Autonomous System Number.

   Local Data Part 1:  A four-octet operator-defined value.

   Local Data Part 2:  A four-octet operator-defined value.




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   The Global Administrator field is intended to allow different
   Autonomous Systems to define Large BGP Communities without collision.
   Implementations MUST allow the operator to specify any value for the
   Global Administrator field.

   There is no significance to the order in which Large BGP Communities
   are encoded in a path attributes field and a receiving speaker MAY
   retransmit them in an order different from which it received them.

   Duplicate Large BGP Communities SHOULD NOT be transmitted.  A
   receiving speaker SHOULD silently remove duplicate Large BGP
   Communities from a BGP UPDATE message.

3.  Aggregation

   If a range of routes is aggregated, then the resulting aggregate
   should have a Large BGP Communities attribute which contains all of
   the Large BGP Communities attributes from all of the aggregated
   routes.

4.  Canonical Representation

   Large BGP Communities MUST be represented as three separate unsigned
   decimal numbers, without leading zeros, in the following order:
   Global Administrator, Local Data 1, Local Data 2.  Numbers MUST not
   be omitted, even when zero.  For example: 64496:4294967295:2 or
   64496:0:0 or (64496, 111, 222).

5.  Reserved Large BGP Community values

   The Large BGP Community attribute values in the following ranges are
   reserved:

            0:0:0 -          0:4294967295:4294967295
        65535:0:0 -      65535:4294967295:4294967295
   4294967295:0:0 - 4294967295:4294967295:4294967295

6.  Error Handling

   The error handling of Large BGP Communities is as follows:

   o  A Large BGP Communities attribute with a length of zero MUST be
      ignored upon receipt and removed when sending.

   o  A Large BGP Communities attribute SHALL be considered malformed if
      its length is not a non-zero multiple of 12 bytes.





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   o  A BGP UPDATE message with a malformed Large BGP Communities
      attribute SHALL be handled using the approach of "treat-as-
      withdraw" as described in section 2 [RFC7606].

   The Large BGP Communities Global Administrator field may contain any
   value, and a Large BGP Communities attribute MUST NOT be considered
   malformed if the Global Administrator field contains an unallocated,
   unassigned or reserved ASN or is set to one of the reserved Large BGP
   Community values defined in Section 5.

7.  Security Considerations

   This extension to BGP has similar security implications as BGP
   Communities [RFC1997].

   This document does not change any underlying security issues
   associated with any other BGP Communities mechanism.  Specifically,
   an AS relying on the Large BGP Communities attribute carried in BGP
   must have trust in every other AS in the path, as any intermediate
   Autonomous System in the path may have added, deleted or altered the
   Large BGP Communities attribute.  Specifying the mechanism to provide
   such trust is beyond the scope of this document.

   Network administrators should note the recommendations in Section 11
   of BGP Operations and Security [RFC7454].

8.  Implementation status - RFC EDITOR: REMOVE BEFORE PUBLICATION

   This section records the status of known implementations of the
   protocol defined by this specification at the time of posting of this
   Internet-Draft, and is based on a proposal described in [RFC7942].
   The description of implementations in this section is intended to
   assist the IETF in its decision processes in progressing drafts to
   RFCs.  Please note that the listing of any individual implementation
   here does not imply endorsement by the IETF.  Furthermore, no effort
   has been spent to verify the information presented here that was
   supplied by IETF contributors.  This is not intended as, and must not
   be construed to be, a catalog of available implementations or their
   features.  Readers are advised to note that other implementations may
   exist.

   As of today these vendors have produced an implementation of Large
   BGP Communities:

   o  Cisco IOS XR

   o  ExaBGP




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   o  GoBGP

   o  BIRD

   o  OpenBGPD

   o  pmacct

   The latest implementation news is tracked at
   http://largebgpcommunities.net/ [1].

9.  IANA Considerations

   IANA has made an Early Allocation of the value 30 (LARGE_COMMUNITY)
   in the "BGP Path Attributes" registry under the "Border Gateway
   Protocol (BGP) Parameters" group and is now asked to make that
   Permanent.

10.  Acknowledgments

   The authors would like to thank Ruediger Volk, Russ White, Acee
   Lindem, Shyam Sethuram, Jared Mauch, Joel M.  Halpern, Jeffrey Haas,
   John Heasley, Gunter van de Velde, Marco Marzetti, Eduardo Ascenco
   Reis, Mark Schouten, Paul Hoogsteder, Martijn Schmidt, Greg Hankins,
   Acee Lindem, Bertrand Duvivier, Barry O'Donovan, Grzegorz Janoszka,
   Linda Dunbar, Marco Davids, Gaurab Raj Upadhaya, Jeff Tantsura, Teun
   Vink, Adam Davenport, Theodore Baschak, Pier Carlo Chiodi, Nabeel
   Cocker, Ian Dickinson, Jan Baggen, Duncan Lockwood, David Farmer,
   Randy Bush, Wim Henderickx, Stefan Plug, Kay Rechthien, Rob Shakir,
   Warren Kumari, Gert Doering, Thomas King, Mikael Abrahamsson, Wesley
   Steehouwer, Sander Steffann, Brad Dreisbach, Martin Millnert,
   Christopher Morrow, Jay Borkenhagen, Arnold Nipper, Joe Provo, Niels
   Bakker, Bill Fenner, Tom Daly, Ben Maddison, Alexander Azimov, Brian
   Dickson, Peter van Dijk, Julian Seifert, Tom Petch, Tom Scholl, Arjen
   Zonneveld, and Remco van Mook for their support, insightful review
   and comments.

11.  References

11.1.  Normative References

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







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

   [RFC6793]  Vohra, Q. and E. Chen, "BGP Support for Four-Octet
              Autonomous System (AS) Number Space", RFC 6793,
              DOI 10.17487/RFC6793, December 2012,
              <http://www.rfc-editor.org/info/rfc6793>.

   [RFC7606]  Chen, E., Ed., Scudder, J., Ed., Mohapatra, P., and K.
              Patel, "Revised Error Handling for BGP UPDATE Messages",
              RFC 7606, DOI 10.17487/RFC7606, August 2015,
              <http://www.rfc-editor.org/info/rfc7606>.

11.2.  Informative References

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

   [RFC7454]  Durand, J., Pepelnjak, I., and G. Doering, "BGP Operations
              and Security", BCP 194, RFC 7454, DOI 10.17487/RFC7454,
              February 2015, <http://www.rfc-editor.org/info/rfc7454>.

   [RFC7942]  Sheffer, Y. and A. Farrel, "Improving Awareness of Running
              Code: The Implementation Status Section", BCP 205,
              RFC 7942, DOI 10.17487/RFC7942, July 2016,
              <http://www.rfc-editor.org/info/rfc7942>.

11.3.  URIs

   [1] http://largebgpcommunities.net

Authors' Addresses

   Jakob Heitz (editor)
   Cisco
   170 West Tasman Drive
   San Jose, CA  95054
   USA

   Email: jheitz@cisco.com








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   Job Snijders (editor)
   NTT Communications
   Theodorus Majofskistraat 100
   Amsterdam  1065 SZ
   NL

   Email: job@ntt.net


   Keyur Patel
   Arrcus, Inc

   Email: keyur@arrcus.com


   Ignas Bagdonas
   Equinix
   London
   UK

   Email: ibagdona.ietf@gmail.com


   Adam Simpson
   Nokia
   600 March Road
   Ottawa  Ontario K2K 2E6
   Canada

   Email: adam.1.simpson@nokia.com


   Nick Hilliard
   INEX
   4027 Kingswood Road
   Dublin  24
   IE

   Email: nick@inex.ie












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