Codification of AS 0 Processing
RFC 7607

Document Type RFC - Proposed Standard (August 2015; Errata)
Updates RFC 4271
Last updated 2015-08-26
Replaces draft-wkumari-idr-as0
Stream IETF
Formats plain text pdf html
Stream WG state WG Document
Consensus Unknown
Document shepherd Susan Hares
IESG IESG state RFC 7607 (Proposed Standard)
Telechat date
Responsible AD Alvaro Retana
IESG note John Scudder (jgs@juniper.net) is the Document Shepherd.
Send notices to idr-chairs@ietf.org, draft-ietf-idr-as0@ietf.org
Internet Engineering Task Force (IETF)                         W. Kumari
Request for Comments: 7607                                        Google
Updates: 4271                                                    R. Bush
Category: Standards Track                      Internet Initiative Japan
ISSN: 2070-1721                                              H. Schiller
                                                                  Google
                                                                K. Patel
                                                           Cisco Systems
                                                             August 2015

                    Codification of AS 0 Processing

Abstract

   This document updates RFC 4271 and proscribes the use of Autonomous
   System (AS) 0 in the Border Gateway Protocol (BGP) OPEN, AS_PATH,
   AS4_PATH, AGGREGATOR, and AS4_AGGREGATOR attributes in the BGP UPDATE
   message.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc7607.

Copyright Notice

   Copyright (c) 2015 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.

Kumari, et al.               Standards Track                    [Page 1]
RFC 7607                     AS 0 Processing                 August 2015

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Notation . . . . . . . . . . . . . . . . . .   2
   2.  Behavior  . . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   3
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   3
   5.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     5.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
     5.2.  Informative References  . . . . . . . . . . . . . . . . .   4
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .   4
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   Autonomous System 0 was listed in the IANA Autonomous System Number
   Registry as "Reserved - May be use [sic] to identify non-routed
   networks" ([IANA.AS_Numbers]).

   [RFC6491] specifies that AS 0 in a Route Origin Attestation (ROA) is
   used to mark a prefix and all its more specific prefixes as not to be
   used in a routing context.  This allows a resource holder to signal
   that a prefix (and the more specifics) should not be routed by
   publishing a ROA listing AS 0 as the only origin.  To respond to this
   signal requires that BGP implementations not accept or propagate
   routes containing AS 0.

   No clear statement that AS 0 was proscribed could be found in any BGP
   specification.  This document corrects this omission, most
   importantly in the case of the AS_PATH.  This represents an update to
   the error handling procedures given in Sections 6.2 and 6.3 of
   [RFC4271] by specifying the behavior in the presence of AS 0.

   At least two implementations discard routes containing AS 0, and this
   document codifies this behavior.

1.1.  Requirements Notation

   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].

Kumari, et al.               Standards Track                    [Page 2]
RFC 7607                     AS 0 Processing                 August 2015

2.  Behavior
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