BGP Support for Four-octet AS Number Space
draft-ietf-idr-rfc4893bis-06

The information below is for an old version of the document
Document Type Active Internet-Draft (idr WG)
Last updated 2012-06-15 (latest revision 2012-04-24)
Stream IETF
Intended RFC status Proposed Standard
Formats plain text pdf html
Stream WG state WG Document
Consensus Unknown
Document shepherd None
IESG IESG state Waiting for AD Go-Ahead
Telechat date
Responsible AD Stewart Bryant
IESG note John Scudder (jgs@juniper.net) is the document shepherd.
Send notices to idr-chairs@tools.ietf.org, draft-ietf-idr-rfc4893bis@tools.ietf.org
Network Working Group                                           Q. Vohra
Internet Draft                                          Juniper Networks
Obsoletes: 4893 (if approved)                                    E. Chen
Intended Status: Standards Track                           Cisco Systems
Expiration Date: Oct 24, 2012                             April 23, 2012

               BGP Support for Four-octet AS Number Space
                    draft-ietf-idr-rfc4893bis-06.txt

Status of this Memo

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

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   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."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/1id-abstracts.html

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html

   This Internet-Draft will expire on October 24, 2012.

Copyright Notice

   Copyright (c) 2012 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.

draft-ietf-idr-rfc4893bis-06.txt                                [Page 1]




Internet Draft      draft-ietf-idr-rfc4893bis-06.txt      April 23, 2012

Abstract

   The Autonomous System (AS) number is encoded as a two-octet entity in
   the base BGP specification. This document describes extensions to BGP
   to carry the Autonomous System numbers as four-octet entities.  This
   document obsoletes RFC 4893.

1. Introduction

   In the base BGP specification [RFC4271] the Autonomous System number
   is encoded as a two-octet entity.  To prepare for the anticipated
   exhaustion of the two-octet AS numbers, this document describes
   extensions to BGP to carry the Autonomous System numbers as four-
   octet entities.

   More specifically, this document defines a BGP capability, "support
   for 4-octet AS number capability", to be used by a BGP speaker to
   indicate its support for the four-octet AS numbers.  Two attributes,
   AS4_PATH and AS4_AGGREGATOR, are introduced that can be used to
   propagate four-octet based AS path information across BGP speakers
   that do not support the four-octet AS numbers.  This document also
   specifies mechanisms for constructing the AS path information from
   the AS_PATH attribute and the AS4_PATH attribute.

   The extensions specified in this document allow a gradual transition
   from 2-octet AS numbers to 4-octet AS numbers.

   This document obsoletes RFC 4893, and a comparison with RFC 4893 is
   provided in Appendix A.

2. Specification of Requirements

   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].

draft-ietf-idr-rfc4893bis-06.txt                                [Page 2]




Internet Draft      draft-ietf-idr-rfc4893bis-06.txt      April 23, 2012

3. Protocol Extensions

   For the purpose of this document we define a BGP speaker that does
   not support the new 4-octet AS number extensions as an OLD BGP
   speaker, and a BGP speaker that supports the new 4-octet AS number
   extensions as a NEW BGP speaker.

   BGP carries the Autonomous System numbers in the "My Autonomous
   System" field of the OPEN message, in the AS_PATH attribute of the
   UPDATE message, and in the AGGREGATOR attribute of the UPDATE
   message.  BGP also carries the Autonomous System numbers in the BGP
   Communities attribute.

   A NEW BGP speaker uses BGP Capability Advertisements [RFC5492] to
   advertise to its neighbors (either internal or external) that it
   supports 4-octet AS number extensions, as specified in this document.

   The Capability that is used by a BGP speaker to convey to its BGP
Show full document text