< draft-ietf-idr-as0-02.txt   draft-ietf-idr-as0-03.txt >
idr W. Kumari idr W. Kumari
Internet-Draft Google Internet-Draft Google
Intended status: Standards Track R. Bush Intended status: Standards Track R. Bush
Expires: July 13, 2012 Internet Initiative Japan Expires: July 19, 2012 Internet Initiative Japan
H. Schiller H. Schiller
Verizon Verizon
K. Patel K. Patel
Cisco Systems Cisco Systems
January 10, 2012 January 16, 2012
Codification of AS 0 processing. Codification of AS 0 processing.
draft-ietf-idr-as0-02 draft-ietf-idr-as0-03
Abstract Abstract
This document proscribes the use of AS 0 in BGP OPEN and AS_PATH / This document proscribes the use of AS 0 in BGP OPEN and AS_PATH /
AS4_PATH BGP attribute. AS4_PATH BGP attribute.
Status of this Memo Status of this Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on July 13, 2012. This Internet-Draft will expire on July 19, 2012.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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1.1. Requirements notation 1.1. Requirements notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
2. Behavior 2. Behavior
A BGP speaker MUST NOT originate or propagate a route with an AS 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 number of zero in the AS_PATH, AS4_PATH, AGGREGATOR or AS4_AGGREGATOR
attributes. A BGP speaker SHOULD NOT generate or propagate an UPDATE attributes.
with zero in any field where an AS number is expected (for example,
"4-Octet AS specific Extended Community" [RFC5668]).
An UPDATE message that contains the AS number of zero in the AS_PATH An UPDATE message that contains the AS number of zero in the AS_PATH
or AS4_PATH attribute MUST be considered as malformed, and be handled or AS4_PATH attribute MUST be considered as malformed, and be handled
by the procedures specified in [I-D.ietf-idr-error-handling]. by the procedures specified in [I-D.ietf-idr-error-handling].
An UPDATE message that contains the AS number of zero in the An UPDATE message that contains the AS number of zero in the
AGGREGATOR or AS4_AGGREGATOR attribute MUST be considered as AGGREGATOR or AS4_AGGREGATOR attribute MUST be considered as
malformed, and be handled by the procedures specified in malformed, and be handled by the procedures specified in
[I-D.ietf-idr-rfc4893bis]. [I-D.ietf-idr-rfc4893bis].
As UPDATE with zero in any other field where an AS number is expected
(for example, "4-Octet AS specific Extended Community" [RFC5668])
SHOULD be treated as malformed and handled appropriately.
If a BGP speaker receives zero as the peer AS in an OPEN message, it 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 MUST abort the connection and send a NOTIFICATION with Error Code
"OPEN Message Error" and subcode "Bad Peer AS" (see [RFC4271] Section "OPEN Message Error" and subcode "Bad Peer AS" (see [RFC4271] Section
6.2). A router MUST NOT initiate a connection claiming to be AS 6.2). A router MUST NOT initiate a connection claiming to be AS
number zero. number zero.
Authors of future protocol extensions that carry the Autonomous
System number are encouraged keep in mind that AS number zero is
reserved and to provide clear direction on how to handle AS number
zero.
3. IANA Considerations 3. IANA Considerations
The IANA is requested to update the Reference for number 0 in the The IANA is requested to update the Reference for number 0 in the
"Autonomous System (AS) Numbers" registry to reference this document. "Autonomous System (AS) Numbers" registry to reference this document.
4. Security Considerations 4. Security Considerations
By allowing resource holders to say that AS 0 is the only valid By allowing resource holders to say that AS 0 is the only valid
origin for a route, we allow them to state that a particular address origin for a route, we allow them to state that a particular address
resource is not in use. By ensuring that all implementations that resource is not in use. By ensuring that all implementations that
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resources. resources.
In addition, by standardizing the behavior upon reception of an In addition, by standardizing the behavior upon reception of an
AS_PATH (or AS4_PATH) containing AS 0, this document makes the AS_PATH (or AS4_PATH) containing AS 0, this document makes the
behavior better defined, and security gotchas often lurk in the behavior better defined, and security gotchas often lurk in the
undefined spaces. undefined spaces.
5. Acknowledgements 5. Acknowledgements
The authors wish to thank Enke Chen, Brian Dickson, Bruno Decraene, The authors wish to thank Enke Chen, Brian Dickson, Bruno Decraene,
Robert Raszuk, Jakob Heitz, Danny McPherson, Chris Morrow, iLya, Robert Raszuk, Jakob Heitz, Danny McPherson, Chris Morrow, iLya, John
Keyur Patel, John Scudder, Jeff Tantsura, Daniel Ginsburg and Susan Scudder, Jeff Tantsura, Daniel Ginsburg and Susan Hares. Apologies
Hares. Apologies to those we may have missed, it was not to those we may have missed, it was not intentional.
intentional.
6. References 6. References
6.1. Normative References 6.1. Normative References
[I-D.ietf-idr-error-handling] [I-D.ietf-idr-error-handling]
Scudder, J., Chen, E., Mohapatra, P., and K. Patel, Scudder, J., Chen, E., Mohapatra, P., and K. Patel,
"Revised Error Handling for BGP UPDATE Messages", "Revised Error Handling for BGP UPDATE Messages",
draft-ietf-idr-error-handling-00 (work in progress), draft-ietf-idr-error-handling-00 (work in progress),
November 2011. November 2011.
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[IANA.AS_Numbers] [IANA.AS_Numbers]
IANA, "Autonomous System (AS) Numbers", IANA, "Autonomous System (AS) Numbers",
<http://www.iana.org/assignments/as-numbers>. <http://www.iana.org/assignments/as-numbers>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway [RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway
Protocol 4 (BGP-4)", RFC 4271, January 2006. Protocol 4 (BGP-4)", RFC 4271, January 2006.
[RFC5668] Rekhter, Y., Sangli, S., and D. Tappan, "4-Octet AS
Specific BGP Extended Community", RFC 5668, October 2009.
6.2. Informative References 6.2. Informative References
[I-D.ietf-sidr-iana-objects] [I-D.ietf-sidr-iana-objects]
Manderson, T., Vegoda, L., and S. Kent, "RPKI Objects Manderson, T., Vegoda, L., and S. Kent, "RPKI Objects
issued by IANA", draft-ietf-sidr-iana-objects-03 (work in issued by IANA", draft-ietf-sidr-iana-objects-03 (work in
progress), May 2011. progress), May 2011.
Appendix A. Changes / Author Notes. Appendix A. Changes / Author Notes.
[RFC Editor: Please remove this section before publication ] [RFC Editor: Please remove this section before publication ]
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broken one into SVN. Apologies to all whose comments I may have broken one into SVN. Apologies to all whose comments I may have
missed... missed...
Changes -01 Changes -01
o The WG thread o The WG thread
http://www.ietf.org/mail-archive/web/idr/current/msg05685.html http://www.ietf.org/mail-archive/web/idr/current/msg05685.html
showed a very strong preference for separating the error showed a very strong preference for separating the error
definition and handling -- the chairs also showed a prefernce to definition and handling -- the chairs also showed a prefernce to
Publish this and point to the error handling that Enke will write. Publish this and point to the error handling that Enke will write.
o The originally suggested text ("An UPDATE message that contains o The originally suggested text ("An UPDATE message that contains
the AS number of zero in the AS-PATH attribute MUST be...") only the AS number of zero in the AS-PATH attribute MUST be...") only
referenced the AS-PATH, readded AS4_PATH, *AGGREGATOR as suggested referenced the AS-PATH, readded AS4_PATH, *AGGREGATOR as suggested
by Robert Raszak and Danny. by Robert Raszak and Danny.
Changes -02 Changes -02
o Fixed the reference for *AGGREGATOR. This required breaking it
o Fixed the refernce for *AGGREGATOR. This required breaking it out out into two sentences / clauses.
into two sentences / clauses.
o Added text on other places where an AS can show up (e.g: "4-Octet o Added text on other places where an AS can show up (e.g: "4-Octet
AS specific Extended Community" [RFC5668]) -- thanks to Keyur. AS specific Extended Community" [RFC5668]) -- 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" [RFC5668]).
o Added *very* generic "Authors of future protocol extensions..."
text
Authors' Addresses Authors' Addresses
Warren Kumari Warren Kumari
Google Google
1600 Amphitheatre Parkway 1600 Amphitheatre Parkway
Mountain View, CA 94043 Mountain View, CA 94043
US US
Email: warren@kumari.net Email: warren@kumari.net
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