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IPv6 Extensions for Route Target Distribution
draft-ietf-idr-bgp-ipv6-rt-constrain-05

Document type: Active Internet-Draft (idr WG)
Document stream: IETF
Last updated: 2014-06-10
Intended RFC status: Unknown
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Network Working Group                                           K. Patel
Internet-Draft                                             Cisco Systems
Intended status: Standards Track                               R. Raszuk
Expires: December 12, 2014                                  NTT MCL Inc.
                                                             M. Djernaes
                                                        Juniper Networks
                                                                 J. Dong
                                                                 M. Chen
                                                     Huawei Technologies
                                                           June 10, 2014

             IPv6 Extensions for Route Target Distribution
                draft-ietf-idr-bgp-ipv6-rt-constrain-05

Abstract

   The current route target distribution specification described in
   RFC4684 defines Route Target NLRIs of maximum length of 12 bytes.
   The IPv6 specific Route Target extended community is defined in
   [RFC5701] as length of 20 bytes.  Since the current specification
   only supports prefixes of maximum length of 12 bytes, the lack of an
   IPv6 specific Route Target reachability information may be a problem
   when an operator wants to use this application in a pure IPv6
   environment.  This document defines an extension that allows BGP to
   exchange longer length IPv6 Route Target prefixes.

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 RFC 2119 [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."

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   This Internet-Draft will expire on December 12, 2014.

Copyright Notice

   Copyright (c) 2014 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.  BGP IPv6 Constrained Route Target Capability  . . . . . . . .   3
   3.  IPv6 Constrained Route Target NLRI Advertisements . . . . . .   3
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   4
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   4
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   The current constrained route distribution specification defined in
   [RFC4684] supports prefixes with a maximum length of 12 bytes.  The
   prefix length needs to be extended to support the IPv6 specific Route
   Target extended community defined in [RFC5701] which is 20 bytes in
   length.  This document defines an extension to the current
   constrained route distribution specification that allows BGP speakers
   to distribute longer length Route Target prefixes.  A new BGP
   capability known as BGP IPv6 Constrained Route Target capability is
   defined as part of extension that allows an exchange of longer length
   Route Target prefixes.  BGP speakers that do not exchange this
   capability MUST use Route Target NLRIs of maximum length of 12 bytes.
   In this way, the current extension would preserve the backward
   compatibility with [RFC4684].

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2.  BGP IPv6 Constrained Route Target Capability

   The "BGP IPV6 Constrained Route Target Capability" is a new BGP
   capability [RFC5492].  The Capability code for this capability is
   specified in the IANA Considerations section of this document.  The
   Capability length field of this capability is zero.

   By advertising this capability to a peer, a BGP speaker conveys to
   the peer that the speaker support the longer length Route Target
   prefixes and the related procedures described in this document.

3.  IPv6 Constrained Route Target NLRI Advertisements

   Route Target membership NLRI is advertised in BGP UPDATE messages
   using the MP_REACH_NLRI and MP_UNREACH_NLRI attributes as defined in
   [RFC4760].  The NLRI field in the MP_REACH_NLRI and MP_UNREACH_NLRI
   is a prefix of 0 to 24 octets, encoded as defined in Section 4 of
   [RFC4760] for all the constrained route distribution.

   This prefix is structured as follows:

                     +-------------------------------+
                     | origin as        (4 octets)   |
                     +-------------------------------+
                     | route target  (8 or 20 octets)|
                     ~                               ~
                     |                               |
                     +-------------------------------+

   Except for the default route target, which is encoded as a zero-
   length prefix, the minimum prefix length is 32 bits.  As the origin-
   AS field cannot be interpreted as a prefix.

   Route targets can then be expressed as prefixes, where, for instance,
   a prefix would encompass all route target extended communities
   assigned by a given Global Administrator [RFC4360] and [RFC5701].
   Alternatively, route target prefixes could be aggregated however if
   done so, then only the Local Administrator field of the Route Target
   can be aggregated.  Route Target Type and the Global Administrator
   Route Target fields MUST not be aggregated.

   The default route target can be used to indicate to a peer the
   willingness to receive all VPN route advertisements such as, for
   instance, the case of a route reflector speaking to one of its PE
   router clients.

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4.  IANA Considerations

   This document defined the IPV6 Constrained Route Target Capability
   for BGP.  The Capability code needs to be assigned by the IANA.

5.  Security Considerations

   This extension to [RFC4684] does not change the underlying security
   issues inherent in the existing BGP and [RFC4684].

6.  Acknowledgements

   The authors would like to thank Pedro Marques, John Scudder, Alton Lo
   and Zhenqiang Li for discussions and review.

7.  References

7.1.  Normative References

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

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

   [RFC4360]  Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
              Communities Attribute", RFC 4360, February 2006.

   [RFC4684]  Marques, P., Bonica, R., Fang, L., Martini, L., Raszuk,
              R., Patel, K., and J. Guichard, "Constrained Route
              Distribution for Border Gateway Protocol/MultiProtocol
              Label Switching (BGP/MPLS) Internet Protocol (IP) Virtual
              Private Networks (VPNs)", RFC 4684, November 2006.

   [RFC5492]  Scudder, J. and R. Chandra, "Capabilities Advertisement
              with BGP-4", RFC 5492, February 2009.

   [RFC5701]  Rekhter, Y., "IPv6 Address Specific BGP Extended Community
              Attribute", RFC 5701, November 2009.

7.2.  Informative References

   [RFC4760]  Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
              "Multiprotocol Extensions for BGP-4", RFC 4760, January
              2007.

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Authors' Addresses

   Keyur Patel
   Cisco Systems
   170 W. Tasman Drive
   San Jose, CA  95134
   USA

   Email: keyupate@cisco.com

   Robert Raszuk
   NTT MCL Inc.
   101 S Ellsworth Avenue Suite 350
   San Mateo, CA  94401
   USA

   Email: robert@raszuk.net

   Martin Djernaes
   Juniper Networks
   1194 N. Mathilda Avenue
   Sunnyvale, CA  94089
   USA

   Email: mdjernaes@juniper.net

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

   Email: jie.dong@huawei.com

   Mach(Guoyi) Chen
   Huawei Technologies
   Huawei Campus, No.156 Beiqing Rd.
   Beijing  100095
   China

   Email: mach.chen@huawei.com

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