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Versions: (draft-ymbk-bgp-extended-messages) 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Network Working Group                                            R. Bush
Internet-Draft                                 Internet Initiative Japan
Updates: 4271 (if approved)                                     K. Patel
Intended status: Standards Track                                 D. Ward
Expires: December 24, 2016                                 Cisco Systems
                                                           June 22, 2016


                    Extended Message support for BGP
                draft-ietf-idr-bgp-extended-messages-13

Abstract

   The BGP specification mandates a maximum BGP message size of 4096
   octets.  As BGP is extended to support newer AFI/SAFIs, there is a
   need to extend the maximum message size beyond 4096 octets.  This
   document updates the BGP specification by providing an extension to
   BGP to extend its current message size from 4096 octets to 65535
   octets.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are to
   be interpreted as described in RFC 2119 [RFC2119] only when they
   appear in all upper case.  They may also appear in lower or mixed
   case as English words, without normative meaning.

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 December 24, 2016.







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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.  BGP Extended Message  . . . . . . . . . . . . . . . . . . . .   2
   3.  Extended message Capability for BGP . . . . . . . . . . . . .   3
   4.  Operation . . . . . . . . . . . . . . . . . . . . . . . . . .   3
   5.  Error Handling  . . . . . . . . . . . . . . . . . . . . . . .   3
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   4
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
     9.2.  Informative References  . . . . . . . . . . . . . . . . .   4
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   The BGP specification RFC4271 [RFC4271] mandates a maximum BGP
   message size of 4096 octets.  As BGP is extended to support newer
   AFI/SAFIs and newer capabilities (e.g.,
   [I-D.ietf-sidr-bgpsec-overview]), there is a need to extend the
   maximum message size beyond 4096 octets.  This draft provides an
   extension to BGP to extend its current message size limit from 4096
   octets to 65535 octets.

2.  BGP Extended Message

   A BGP message over 4096 octets in length is a BGP Extended Message.

   BGP Extended Messages have maximum message size of 65535 octets.  The
   smallest message that may be sent consists of a BGP header without a
   data portion (19 octets).




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   Multi-octet fields MUST be in network byte order.

3.  Extended message Capability for BGP

   To advertise the BGP Extended Message Capability to a peer, a BGP
   speaker uses BGP Capabilities Advertisement [RFC5492].  By
   advertising the BGP Extended Message Capability to a peer, a BGP
   speaker conveys that it is able to send, receive, and properly handle
   BGP Extended Messages.

   A peer which does not advertise this capability MUST NOT send BGP
   Extended Messages, and BGP Extended Messages MUST NOT be sent to it.

   The BGP Extended Message Capability is a new BGP Capability [RFC5492]
   defined with Capability code TBD and Capability length 0.

4.  Operation

   A BGP speaker that is willing to send and receive BGP Extended
   Messages from its peer should advertise the BGP Extended Message
   Capability to its peer using BGP Capabilities Advertisement
   [RFC5492].  A BGP speaker may send extended messages to its peer only
   if it has received the Extended Message Capability from its peer.

   An implementation that supports the BGP Extended Messages MUST be
   prepared to receive an OPEN message that is larger than 4096 bytes.

   Applications generating messages which might be encapsulated within
   BGP messages MUST limit the size of their payload to take into
   account the maximum message size and all encapsulation overheads on
   the path the encapsulated data are expected to traverse.

5.  Error Handling

   A BGP speaker that has the ability to use extended messages but has
   not advertised the BGP Extended Messages capability, presumably due
   to configuration, SHOULD NOT accept an extended message.  A speaker
   MAY implement a more liberal policy and accept extended messages even
   from a peer that has not advertised the capability.

   However, a BGP speaker that does not advertise the BGP Extended
   Messages capability might also genuinely not support extended
   messages.  Such a speaker would be expected to follow the error
   handling procedures of [RFC4271], Section 6.1, and reset the session
   with a Bad Message Length NOTIFICATION if it receives an extended
   message.  A speaker that treats an improper extended message as a
   fatal error, as described in the preceding paragraph, MUST do
   likewise.



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   The inconsistency between the local and remote BGP speakers MUST be
   reported via syslog and/or SNMP.

6.  Acknowledgements

   The authors thank Enke Chen, Susan Hares, John Scudder, John Levine,
   and Job Snijders for their input.

7.  IANA Considerations

   The IANA is requested to register a new BGP Capability Code to be
   named BGP Extended Message Capability and referring to this document.

   Registry:  BGP Capability Code

   Value    Description                               Document
   -----    -----------------------------------       -------------
   64       Graceful Restart Capability               [RFC4724]
   ....
   72       CP-ORF Capability                         [RFC7543]
   ...
   TBD      BGP-Extended Message                      [this draft]

8.  Security Considerations

   This extension to BGP does not change BGP's underlying security
   issues.  It does enable large BGPsec BGPSEC_PATHs, see
   [I-D.ietf-sidr-bgpsec-protocol]

9.  References

9.1.  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.

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

9.2.  Informative References

   [I-D.ietf-sidr-bgpsec-overview]
              Lepinski, M. and S. Turner, "An Overview of BGPSEC",
              draft-ietf-sidr-bgpsec-overview-02 (work in progress), May
              2012.



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   [I-D.ietf-sidr-bgpsec-protocol]
              Lepinski, M., "BGPSEC Protocol Specification", draft-ietf-
              sidr-bgpsec-protocol-07 (work in progress), February 2013.

Authors' Addresses

   Randy Bush
   Internet Initiative Japan
   5147 Crystal Springs
   Bainbridge Island, Washington  98110
   US

   Email: randy@psg.com


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

   Email: keyupate@cisco.com


   Dave Ward
   Cisco Systems
   170 W. Tasman Drive
   San Jose, CA  95134
   USA

   Email: dward@cisco.com




















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