Internet DRAFT - draft-ietf-idr-as0
draft-ietf-idr-as0
idr W. Kumari
Internet-Draft Google
Updates: 4271 (if approved) R. Bush
Intended status: Standards Track Internet Initiative Japan
Expires: February 27, 2013 H. Schiller
Verizon
K. Patel
Cisco Systems
August 26, 2012
Codification of AS 0 processing.
draft-ietf-idr-as0-06
Abstract
This document updates RFC 4271 and proscribes the use of Autonomous
System (AS) 0 in the Border Gateway Protocol (BGP) OPEN and AS_PATH /
AS4_PATH BGP attribute.
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
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This Internet-Draft will expire on February 27, 2013.
Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved.
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements notation . . . . . . . . . . . . . . . . . . . 3
2. Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . . 4
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 4
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 4
6.1. Normative References . . . . . . . . . . . . . . . . . . . 4
6.2. Informative References . . . . . . . . . . . . . . . . . . 5
Appendix A. Changes / Author Notes. . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
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1. Introduction
Autonomous System 0 is listed in the IANA Autonomous System Number
Registry as "Reserved - May be use to identify non-routed networks"
([IANA.AS_Numbers]).
[RFC6491] specifies that AS number zero 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 AS0 as the only origin. To respond to
this signal requres that BGP implementations do not accept or
propagate routes containing AS0.
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 [RFC4271] Sections 6.2 and 6.3
by specifying the behavior in the presence of AS0.
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].
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 [I-D.ietf-idr-error-handling].
An UPDATE message that contains the AS number of zero in the AS4_PATH
or AS4_AGGREGATOR attribute MUST be considered as malformed, and be
handled by the procedures specified in [I-D.ietf-idr-rfc4893bis].
If a BGP speaker receives zero as the peer AS in an OPEN message, it
MUST abort the connection and send a NOTIFICATION with Error Code
"OPEN Message Error" and subcode "Bad Peer AS" (see [RFC4271] Section
6.2). A router MUST NOT initiate a connection claiming to be AS
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number zero.
Authors of future protocol extensions that carry the Autonomous
System number are encouraged to keep in mind that AS number zero is
reserved and to provide clear direction on how to handle AS number
zero.
3. IANA Considerations
The IANA is requested to update the Reference for number 0 in the
"Autonomous System (AS) Numbers" registry to reference this document.
4. Security Considerations
By allowing a Resource Public Key Infrastructure (RPKI) resource
holder to issue a ROA saying that AS 0 is the only valid origin for a
route, we allow them to state that a particular address resource is
not in use. By ensuring that all implementations that see AS 0 in a
route ignore that route, we prevent a malicious party from announcing
routes containing AS 0 in an attempt to hijack those resources.
In addition, by standardizing the behavior upon reception of an
AS_PATH (or AS4_PATH) containing AS 0, this document makes the
behavior better defined.
5. Acknowledgements
The authors wish to thank Elwyn Davies, Enke Chen, Brian Dickson,
Bruno Decraene, Robert Raszuk, Jakob Heitz, Danny McPherson, Chris
Morrow, iLya, John Scudder, Jeff Tantsura, Daniel Ginsburg and Susan
Hares. Apologies to those we may have missed, it was not
intentional.
6. References
6.1. Normative References
[I-D.ietf-idr-error-handling]
Scudder, J., Chen, E., Mohapatra, P., and K. Patel,
"Revised Error Handling for BGP UPDATE Messages",
draft-ietf-idr-error-handling-01 (work in progress),
December 2011.
[I-D.ietf-idr-rfc4893bis]
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Vohra, Q. and E. Chen, "BGP Support for Four-octet AS
Number Space", draft-ietf-idr-rfc4893bis-06 (work in
progress), April 2012.
[IANA.AS_Numbers]
IANA, "Autonomous System (AS) Numbers",
<http://www.iana.org/assignments/as-numbers>.
[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.
6.2. Informative References
[RFC6491] Manderson, T., Vegoda, L., and S. Kent, "Resource Public
Key Infrastructure (RPKI) Objects Issued by IANA",
RFC 6491, February 2012.
Appendix A. Changes / Author Notes.
[RFC Editor: Please remove this section before publication ]
Draft accepted as IDR Doc, notes reset. Please see notes for
draft-wkumari-idr-as0.xml for prior comments.
Changes -00.
o Added AS4_PATH -- Robert Raszuk.
o Change "bgp listener" to "bgp speaker" -- Enke Chen
o Consistent use of AS_PATH (v., AS-PATH and AS PATH) -- Danny
McPherson
o New text for Sec 2 P1 -- Enke / Keyur / Scudder,
http://www.ietf.org/mail-archive/web/idr/current/msg05786.html
o I made a boo boo -- I had the file open in 2 editors, made changes
in one and overwrote them by saving on the "other, then checked
the broken one into SVN. Apologies to all whose comments I may
have missed...
Changes -01
o The WG thread
http://www.ietf.org/mail-archive/web/idr/current/msg05685.html
showed a very strong preference for separating the error
definition and handling -- the chairs also showed a prefernce to
Publish this and point to the error handling that Enke will write.
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o The originally suggested text ("An UPDATE message that contains
the AS number of zero in the AS-PATH attribute MUST be...") only
referenced the AS-PATH, readded AS4_PATH, *AGGREGATOR as suggested
by Robert Raszak and Danny.
Changes -02
o Fixed the reference for *AGGREGATOR. This required breaking it
out into two sentences / clauses.
o Added text on other places where an AS can show up (e.g: "4-Octet
AS specific Extended Community" [5668]) -- thanks to Keyur.
Changes - 03
o Removed text on other places where an AS can show up (e.g:
"4-Octet AS specific Extended Community" [5668]).
o Added *very* generic "Authors of future protocol extensions..."
text
Changes -04
o Looks like the draft needs an 'Updates: RFC 4271' header. Can you
make the change? -- JGS.
o "You have things a bit scrambled in these two paragraphs" -- JGS
(whoops!).
o Editorial: I suggest dropping the parentheses in... JGS.
o Added "This document updates rfc 4271" to keep IDNITs happy...
o Bumped refs: draft-ietf-sidr-iana-objects has been published as
RFC 6491, idr-error is now -01, 4893bis is now -06
Changes - 05
o Added something to the intro saying what we update and why. This
was in the abstract, but I didn't have it in the intro. Stupid.
Changes - 06
o Incorporated some comments / clarifications from Gen-ART review
(Elwyn Davies)
o Expaned acronyms.
o RFC 6491 fix - clarified what it actually said and what
implications are.
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Authors' Addresses
Warren Kumari
Google
1600 Amphitheatre Parkway
Mountain View, CA 94043
US
Email: warren@kumari.net
Randy Bush
Internet Initiative Japan
5147 Crystal Springs
Bainbridge Island, WA 98110
US
Email: randy@psg.com
Heather Schiller
Verizon
22001 Loudoun County Parkway
Ashburn 20147
US
Email: heather.schiller@verizon.com
Keyur Patel
Cisco Systems
170 W. Tasman Drive
San Jose, CA 95134
USA
Phone:
Fax:
Email: keyupate@cisco.com
URI:
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