Codification of AS 0 Processing
RFC 7607
| Document | Type |
RFC - Proposed Standard
(August 2015; No errata)
Updates RFC 4271
Was draft-ietf-idr-as0 (idr WG)
|
|
|---|---|---|---|
| Last updated | 2020-07-29 | ||
| Replaces | draft-wkumari-idr-as0 | ||
| Stream | IETF | ||
| Formats | plain text html pdf htmlized bibtex | ||
| Reviews | |||
| Stream | WG state | WG Document | |
| Document shepherd | Susan Hares | ||
| IESG | IESG state | RFC 7607 (Proposed Standard) | |
| Consensus Boilerplate | Unknown | ||
| Telechat date | |||
| Responsible AD | Alvaro Retana | ||
| IESG note | John Scudder (jgs@juniper.net) is the Document Shepherd. | ||
| Send notices to | (None) | ||
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
A BGP speaker MUST NOT originate or propagate a route with an AS
number of zero in the AS_PATH, AS4_PATH, AGGREGATOR, or
AS4_AGGREGATOR attributes.
An UPDATE message that contains the AS number of zero in the AS_PATH
or AGGREGATOR attribute MUST be considered as malformed and be
handled by the procedures specified in [RFC7606].
An UPDATE message that contains the AS number of zero in the AS4_PATH
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