Codification of AS 0 Processing
RFC 7607
Document | Type |
RFC - Proposed Standard
(August 2015; Errata)
Updates RFC 4271
Was draft-ietf-idr-as0 (idr WG)
|
|
---|---|---|---|
Last updated | 2015-10-14 | ||
Replaces | draft-wkumari-idr-as0 | ||
Stream | IETF | ||
Formats | plain text pdf html 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_PATHShow full document text