draft-ietf-l3vpn-as4octet-ext-community-03.txt   rfc5668.txt 
Network Working Group Yakov Rekhter (Juniper Networks) Network Working Group Y. Rekhter
Internet Draft Srihari R. Sangli (Cisco Systems) Request for Comments: 5668 Juniper Networks
Expiration Date: September 2009 Daniel Tappan Category: Standards Track S. Sangli
Intended Status: Proposed Standard Cisco Systems
D. Tappan
Four-octet AS Specific BGP Extended Community Consultant
October 2009
draft-ietf-l3vpn-as4octet-ext-community-03.txt
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the 4-Octet AS Specific BGP Extended Community
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Abstract
Task Force (IETF), its areas, and its working groups. Note that other
groups may also distribute working documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months This document defines a new type of a BGP extended community, which
and may be updated, replaced, or obsoleted by other documents at any carries a 4-octet Autonomous System (AS) number.
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at Status of This Memo
http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at This document specifies an Internet standards track protocol for the
http://www.ietf.org/shadow.html. Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
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RFC 5668 4-Octet AS Specific Extended Community October 2009
not be created outside the IETF Standards Process, except to format not be created outside the IETF Standards Process, except to format
it for publication as an RFC or to translate it into languages other it for publication as an RFC or to translate it into languages other
than English. than English.
Abstract 1. Introduction
This document defines a new type of a BGP extended community - four- This document defines a new type of BGP extended community [RFC4360]:
octet AS specific extended community. This community allows to carry a 4-octet AS specific extended community. This type of extended
4 octet autonomous system numbers. community is similar to the 2-octet AS specific extended community,
except that it can carry a 4-octet Autonomous System number.
Specification of Requirements 1.1. Specification of Requirements
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 RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
1. Introduction 2. 4-Octet AS Specific Extended Community
This document defines a new type of BGP extended community
([RFC4360]) - four-octet AS specific extended community. This type of
extended community is similar to the two-octet AS specific extended
community, except that it can carry a four octets autonomous system
number.
2. Four-octet AS specific extended community
This is an extended type with Type Field comprising of 2 octets and This is an extended type with a Type field comprising 2 octets and a
Value Field comprising of 6 octets. Value field comprising 6 octets.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x02 or 0x42 | Sub-Type | Global Administrator : | 0x02 or 0x42 | Sub-Type | Global Administrator :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: Global Administrator (cont.) | Local Administrator | : Global Administrator (cont.) | Local Administrator |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The value of the high-order octet of this extended type is either The value of the high-order octet of this extended type is either
0x02 (for transitive communities) or 0x42 (for non-transitive commu- 0x02 (for transitive communities) or 0x42 (for non-transitive
nities). The low-order octet of this extended type is used to communities). The low-order octet of this extended type is used to
indicate sub-types. indicate sub-types.
The Value Field consists of two sub-fields: The Value field consists of 2 sub-fields:
Global Administrator sub-field: 4 octets Global Administrator sub-field: 4 octets
This sub-field contains a 4-octets Autonomous System number This sub-field contains a 4-octet Autonomous System number
assigned by IANA. assigned by IANA.
RFC 5668 4-Octet AS Specific Extended Community October 2009
Local Administrator sub-field: 2 octets Local Administrator sub-field: 2 octets
The organization identified by Autonomous System number in the The organization identified by the Autonomous System number in
Global Administrator sub-field, can encode any information in the Global Administrator sub-field can encode any information
this sub-field. The format and meaning of the value encoded in in this sub-field. The format and meaning of the value encoded
this sub-field should be defined by the sub-type of the commu- in this sub-field should be defined by the sub-type of the
nity. community.
3. Considerations for two-octet Autonomous Systems 3. Considerations for 2-Octet Autonomous Systems
As per [RFC4893], a two-octet Autonomous System number can be con- As per [RFC4893], a 2-octet Autonomous System number can be converted
verted into a 4-octet Autonomous System number by setting the two into a 4-octet Autonomous System number by setting the 2 high-order
high-order octets of the 4-octet field to zero. octets of the 4-octet field to zero.
As a consequence, at least in principle an autonomous system that As a consequence, at least in principle, an Autonomous System that
uses a two-octet Autonomous System number could use either two-octet uses a 2-octet Autonomous System number could use either 2-octet or
or four-octet AS specific extended communities. This is undesirable, 4-octet AS specific extended communities. This is undesirable, as
as both communities would be treated as different, even if they had both communities would be treated as different, even if they had the
the same Sub-Type and Local Administrator values. same Sub-Type and Local Administrator values.
Therefore, for backward compatibility with existing deployments, and Therefore, for backward compatibility with existing deployments and
to avoid inconsistencies between two-octet and four-octet specific to avoid inconsistencies between 2-octet and 4-octet specific
extended communities, autonomous systems that use two-octet extended communities, Autonomous Systems that use 2-octet Autonomous
Autonomous System numbers SHOULD use two-octet AS specific extended System numbers SHOULD use 2-octet AS specific extended communities
communities rather than four-octet AS specific extended communities. rather than 4-octet AS specific extended communities.
4. IANA Considerations 4. IANA Considerations
This document defines a class of extended communities called four- This document defines a class of extended communities, called 4-octet
octet AS specific extended community for which the IANA is to create AS specific extended communities, for which the IANA has created and
and maintain a registry entitled Four-octet AS Specific Extended Com- will maintain a registry entitled Four-octet AS Specific Extended
munity. All the communities in this class are of extended Types. Community. All the communities in this class are of extended Types.
Future assignment are to be made using the "First Come First Served" Future assignments are to be made using the "First Come First Served"
policy defined in [RFC5226]. The Type values for the transitive com- policy defined in [RFC5226]. The Type values for the transitive
munities of the four-octet AS specific extended community class are communities of the 4-octet AS specific extended community class are
0x0200-0x02ff, and for the non-transitive communities of that class 0x0200-0x02ff; for the non-transitive communities of that class, they
are 0x4200-0x42ff. Assignments consist of a name and the value. are 0x4200-0x42ff. Assignments consist of a name and the value.
This document makes the following assignments for the four-octet AS This document makes the following assignments for the 4-octet AS
specific extended community: specific extended community:
Name Type Value Name Type Value
---- ---------- ---- ----------
four-octet AS specific Route Target 0x0202 four-octet AS specific Route Target 0x0202
four-octet AS specific Route Origin 0x0203 four-octet AS specific Route Origin 0x0203
5. Security Considerations RFC 5668 4-Octet AS Specific Extended Community October 2009
All the security considerations for BGP Extended Communities apply 5. Security Considerations
here.
6. Acknowledgements This document does not add new security issues. All the security
considerations for BGP extended communities apply here. At the time
that this document was written, there were significant efforts
underway to improve the security properties of BGP. For examples of
documents that have been produced up to this time of publication, see
[RFC4593] and [SIDR].
There is a potential serious issue if a malformed, optional
transitive attribute is received. This issue and the steps to avoid
it are discussed in [OPT_TRANS].
6. Acknowledgements
Thanks to Bruno Decraene for his contributions to this document. Thanks to Bruno Decraene for his contributions to this document.
7. Normative References 7. References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 7.1. Normative References
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5226] Narten, T., Alvestrand, H., "Guidelines for Writing an IANA [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Considerations Section in RFCs", RFC5226, May 2008. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4360] Srihari R. Sangli, Daniel Tappan, Yakov Rekhter, "BGP [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
Extended Communities Attribute", RFC 4360, February 2006. IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008.
[RFC4893] Vohra, Q., Chen, E., "BGP Support for Four-octet AS Number [RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
Space", RFC 4893, May 2007. Communities Attribute", RFC 4360, February 2006.
8. Non-normative References [RFC4893] Vohra, Q. and E. Chen, "BGP Support for Four-octet AS
Number Space", RFC 4893, May 2007.
9. Author Information 7.2. Informative References
[OPT_TRANS] Scudder, J., and E. Chen, "Error Handling for Optional
Transitive BGP Attributes", Work in Progress, April 2009.
[RFC4593] Barbir, A., Murphy, S., and Y. Yang, "Generic Threats to
Routing Protocols", RFC 4593, October 2006.
[SIDR] Lepinski, M. and S. Kent, "An Infrastructure to Support
Secure Internet Routing", Work in Progress, July 2009.
RFC 5668 4-Octet AS Specific Extended Community October 2009
Authors' Addresses
Yakov Rekhter Yakov Rekhter
Juniper Networks, Inc. Juniper Networks, Inc.
e-mail: yakov@juniper.net EMail: yakov@juniper.net
Srihari R. Sangli Srihari R. Sangli
Cisco Systems, Inc. Cisco Systems, Inc.
e-mail: rsrihari@cisco.com EMail: rsrihari@cisco.com
Dan Tappan Dan Tappan
Boxborough MA Boxborough MA
e-mail: Dan.Tappan@Gmail.com EMail: Dan.Tappan@Gmail.com
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