4-Octet AS Specific BGP Extended Community
RFC 5668
Network Working Group Y. Rekhter
Request for Comments: 5668 Juniper Networks
Category: Standards Track S. Sangli
Cisco Systems
D. Tappan
Consultant
October 2009
4-Octet AS Specific BGP Extended Community
Abstract
This document defines a new type of a BGP extended community, which
carries a 4-octet Autonomous System (AS) number.
Status of This Memo
This document specifies an Internet standards track protocol for the
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.
Copyright Notice
Copyright (c) 2009 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 BSD License.
This document may contain material from IETF Documents or IETF
Contributions published or made publicly available before November
10, 2008. The person(s) controlling the copyright in some of this
material may not have granted the IETF Trust the right to allow
modifications of such material outside the IETF Standards Process.
Without obtaining an adequate license from the person(s) controlling
the copyright in such materials, this document may not be modified
outside the IETF Standards Process, and derivative works of it may
Rekhter, et al. Standards Track [Page 1]
RFC 5668 4-Octet AS Specific Extended Community October 2009
not be created outside the IETF Standards Process, except to format
it for publication as an RFC or to translate it into languages other
than English.
1. Introduction
This document defines a new type of BGP extended community [RFC4360]:
a 4-octet AS specific extended community. This type of extended
community is similar to the 2-octet AS specific extended community,
except that it can carry a 4-octet Autonomous System number.
1.1. Specification of Requirements
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 RFC 2119 [RFC2119].
2. 4-Octet AS Specific Extended Community
This is an extended type with a Type field comprising 2 octets and a
Value field comprising 6 octets.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x02 or 0x42 | Sub-Type | Global Administrator :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: Global Administrator (cont.) | Local Administrator |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The value of the high-order octet of this extended type is either
0x02 (for transitive communities) or 0x42 (for non-transitive
communities). The low-order octet of this extended type is used to
indicate sub-types.
The Value field consists of 2 sub-fields:
Global Administrator sub-field: 4 octets
This sub-field contains a 4-octet Autonomous System number
assigned by IANA.
Rekhter, et al. Standards Track [Page 2]
RFC 5668 4-Octet AS Specific Extended Community October 2009
Local Administrator sub-field: 2 octets
The organization identified by the Autonomous System number in
the Global Administrator sub-field can encode any information
in this sub-field. The format and meaning of the value encoded
in this sub-field should be defined by the sub-type of the
community.
3. Considerations for 2-Octet Autonomous Systems
As per [RFC4893], a 2-octet Autonomous System number can be converted
into a 4-octet Autonomous System number by setting the 2 high-order
octets of the 4-octet field to zero.
As a consequence, at least in principle, an Autonomous System that
Show full document text