Large BGP Communities
draft-ietf-idr-large-community-01
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft that was ultimately published as RFC 8092.
|
|
|---|---|---|---|
| Authors | Jakob Heitz , Keyur Patel , Job Snijders , Ignas Bagdonas , Adam Simpson | ||
| Last updated | 2016-10-01 | ||
| Replaces | draft-heitz-idr-large-community | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
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draft-ietf-idr-large-community-01
IDR J. Heitz
Internet-Draft Cisco
Intended status: Standards Track K. Patel
Expires: April 4, 2017 Arrcus
J. Snijders
NTT
I. Bagdonas
Equinix
A. Simpson
Nokia
October 1, 2016
Large BGP Communities
draft-ietf-idr-large-community-01
Abstract
This document describes the Large BGP Community attribute, an
extension to BGP (RFC 4271). This attribute provides a mechanism to
signal opaque information within separate namespaces to aid in
routing management. The attribute is suitable for use in 4-byte ASNs
(RFC 6793).
Requirements Language
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].
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
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 4, 2017.
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Copyright Notice
Copyright (c) 2016 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.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Large BGP Communities Attribute . . . . . . . . . . . . . . . 3
3. Aggregation . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Textual Representation . . . . . . . . . . . . . . . . . . . 4
5. Reserved Large BGP Community values . . . . . . . . . . . . . 4
6. Error Handling . . . . . . . . . . . . . . . . . . . . . . . 5
7. Security Considerations . . . . . . . . . . . . . . . . . . . 5
8. Implementation status - RFC EDITOR: REMOVE BEFORE PUBLICATION 5
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
11.1. Normative References . . . . . . . . . . . . . . . . . . 7
11.2. Informative References . . . . . . . . . . . . . . . . . 7
11.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
BGP implementations typically support a routing policy language to
control the distribution of routing information. Network operators
attach BGP communities to routes to identify intrinsic properties of
these routes. These properties may include information such as the
route origin location, or specification of a routing policy action to
be taken, or one that has been taken, and may apply to an individual
route or to a group of routes. Because BGP communities are optional
transitive BGP attributes, BGP communities may be acted upon or
otherwise used by routing policies in other Autonomous Systems (ASes)
on the Internet.
[RFC1997] BGP Communities Attributes are four-octet values split into
two individual two-octet words. The most significant word is usually
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interpreted as an Autonomous System Number (ASN) and the least
significant word is a locally defined value whose meaning is assigned
by the operator of the Autonomous System in the most significant
word.
Since the adoption of four-octet ASNs [RFC6793], the BGP Communities
Attribute can no longer accommodate this encoding, as the
specification in [RFC1997] contains only four octets. This does not
allow operators to specify any locally significant values.
To address these shortcomings, this document defines a Large
Community BGP Attribute encoded as one or more 12-octet values, each
consisting of a four-octet ASN and two four-octet operator-defined
values, each of which can be used to denote properties or actions
significant to that ASN.
2. Large BGP Communities Attribute
This document creates the Large Communities BGP path attribute as an
optional transitive attribute of variable length. All routes with
the Large Communities attribute belong to the community specified in
the attribute.
The attribute consists of one or more 12-octet values. Each 12-octet
Large Communities value represents three 4-octet values, as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Global Administrator |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local Data Part 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local Data Part 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Global Administrator: A four-octet namespace identifier. This
SHOULD be an Autonomous System Number assigned by IANA.
Local Data Part 1: A four-octet operator-defined value.
Local Data Part 2: A four-octet operator-defined value.
The Global Administrator field is intended to allow different
Autonomous Systems to define Large Communities without collision.
Implementations MUST allow the operator to specify any value for the
Global Administrator field.
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There is no significance to the order in which Large Communities are
encoded in a path attributes field and a receiving speaker MAY
retransmit them in an order different from which it received them.
Duplicate Large Communities SHOULD NOT be transmitted. A receiving
speaker SHOULD silently remove duplicate Large Communities from a BGP
UPDATE message.
There are no routing semantics implied by the Global Administrator
field.
3. Aggregation
If a range of routes is aggregated and the resulting aggregates
attribute section does not carry the ATOMIC_AGGREGATE attribute, then
the resulting aggregate should have a Large Communities path
attribute which contains all of the large communities from all of the
aggregated routes.
4. Textual Representation
BGP Communities [RFC1997] are usually represented in routing policy
languages as two individual two-octet unsigned integers separated by
a colon; for example, 64496:12345.
BGP Large Communities implementations MUST represent Large
Communities in a manner similar to their representation of BGP
Communities [RFC1997]. Large Communities MUST be represented as
three separate four-octet unsigned integers in decimal format with no
leading zeros. These integers MUST NOT be omitted, even when zero.
For example, 64496:4294967295:2 or 64496:0:0.
Vendors MAY provide other textual representations. For example, a
vendor's routing policy language may use a separator other than a
colon or may require keywords or characters prepending or postpending
the Large Communities attribute. Such differences are permitted.
However, each implementation MUST make a representation available
that depicts the integers in decimal and in the following order:
Global Administrator, Local Data Part 1, Local Data Part 2.
5. Reserved Large BGP Community values
The Large BGP Community attribute values in the following ranges are
reserved:
0:0:0 - 0:4294967295:4294967295
65535:0:0 - 65535:4294967295:4294967295
4294967295:0:0 - 4294967295:4294967295:4294967295
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6. Error Handling
The error handling of Large Communities is as follows:
o A Large Communities BGP Path Attribute with a length of zero MUST
be ignored upon receipt and removed when sending.
o A Large Communities attribute SHALL be considered malformed if its
length is not a non-zero multiple of 12 bytes.
o A BGP UPDATE message with a malformed Large Communities attribute
SHALL be handled using the approach of "treat-as-withdraw" as
described in section 2 [RFC7606].
The BGP Large Communities Global Administrator field may contain any
value, and a Large Communities attribute MUST NOT be considered
malformed if the Global Administrator field contains an unallocated,
unassigned or reserved ASN or is set to one of the reserved Large BGP
Community values defined in Section 5.
A receiving speaker MUST NOT consider duplicate Large Communities
attributes in a BGP UPDATE message to be malformed.
7. Security Considerations
This extension to BGP has similar security implications as BGP
Communities [RFC1997] and BGP Extended Communities [RFC4360].
This document does not change any underlying security issues
associated with any other BGP Communities mechanism. Specifically,
an AS relying on the Large BGP Community attribute carried in BGP
must have trust in every other AS in the path, as any intermediate
Autonomous System in the path may have added, deleted or altered the
Large BGP Community attribute. Specifying the mechanism to provide
such trust is beyond the scope of this document.
Network administrators should note the recommendations in Section 11
of BGP Operations and Security [RFC7454].
8. Implementation status - RFC EDITOR: REMOVE BEFORE PUBLICATION
This section records the status of known implementations of the
protocol defined by this specification at the time of posting of this
Internet-Draft, and is based on a proposal described in [RFC7942].
The description of implementations in this section is intended to
assist the IETF in its decision processes in progressing drafts to
RFCs. Please note that the listing of any individual implementation
here does not imply endorsement by the IETF. Furthermore, no effort
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has been spent to verify the information presented here that was
supplied by IETF contributors. This is not intended as, and must not
be construed to be, a catalog of available implementations or their
features. Readers are advised to note that other implementations may
exist.
As of today these vendors have produced an implementation of Large
BGP Community:
o Cisco IOS XR
o ExaBGP
o GoBGP
o BIRD
The latest implementation news is tracked at
http://largebgpcommunities.net/ [1].
9. IANA Considerations
IANA has assigned value 30 (LARGE_COMMUNITY Attribute) in the "BGP
Path Attributes" sub-registry under the "Border Gateway Protocol
(BGP) Parameters" registry.
10. Acknowledgments
The authors would like to thank Ruediger Volk, Russ White, Acee
Lindem, Shyam Sethuram, Jared Mauch, Joel M. Halpern, Nick Hilliard,
Jeffrey Haas, John Heasley, Gunter van de Velde, Marco Marzetti,
Eduardo Ascenco Reis, Mark Schouten, Paul Hoogsteder, Martijn
Schmidt, Greg Hankins, Acee Lindem, Bertrand Duvivier, Barry
O'Donovan, Grzegorz Janoszka, Linda Dunbar, Marco Davids, Gaurab Raj
Upadhaya, Jeff Tantsura, Teun Vink, Adam Davenport, Theodore Baschak,
Pier Carlo Chiodi, Nabeel Cocker, Ian Dickinson, Jan Baggen, Duncan
Lockwood, David Farmer, Randy Bush, Wim Henderickx, Stefan Plug, Kay
Rechthien, Rob Shakir, Warren Kumari, Gert Doering, Thomas King,
Mikael Abrahamsson, Wesley Steehouwer, Sander Steffann, Brad
Dreisbach, Martin Millnert, Christopher Morrow, Jay Borkenhagen,
Arnold Nipper, Joe Provo, Niels Bakker, Bill Fenner, Tom Daly, Ben
Maddison, Alexander Azimov, Brian Dickson, Peter van Dijk, Julian
Seifert, Tom Petch and Tom Scholl for their support, insightful
review and comments.
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11. References
11.1. Normative References
[RFC1997] Chandra, R., Traina, P., and T. Li, "BGP Communities
Attribute", RFC 1997, DOI 10.17487/RFC1997, August 1996,
<http://www.rfc-editor.org/info/rfc1997>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC6793] Vohra, Q. and E. Chen, "BGP Support for Four-Octet
Autonomous System (AS) Number Space", RFC 6793,
DOI 10.17487/RFC6793, December 2012,
<http://www.rfc-editor.org/info/rfc6793>.
[RFC7606] Chen, E., Ed., Scudder, J., Ed., Mohapatra, P., and K.
Patel, "Revised Error Handling for BGP UPDATE Messages",
RFC 7606, DOI 10.17487/RFC7606, August 2015,
<http://www.rfc-editor.org/info/rfc7606>.
11.2. Informative References
[RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
Communities Attribute", RFC 4360, DOI 10.17487/RFC4360,
February 2006, <http://www.rfc-editor.org/info/rfc4360>.
[RFC7454] Durand, J., Pepelnjak, I., and G. Doering, "BGP Operations
and Security", BCP 194, RFC 7454, DOI 10.17487/RFC7454,
February 2015, <http://www.rfc-editor.org/info/rfc7454>.
[RFC7942] Sheffer, Y. and A. Farrel, "Improving Awareness of Running
Code: The Implementation Status Section", BCP 205,
RFC 7942, DOI 10.17487/RFC7942, July 2016,
<http://www.rfc-editor.org/info/rfc7942>.
11.3. URIs
[1] https://largebgpcommunities.net
Authors' Addresses
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Jakob Heitz
Cisco
170 West Tasman Drive
San Jose, CA 95054
USA
Email: jheitz@cisco.com
Keyur Patel
Arrcus, Inc
Email: keyur@arrcus.com
Job Snijders
NTT Communications
Theodorus Majofskistraat 100
Amsterdam 1065 SZ
NL
Email: job@ntt.net
Ignas Bagdonas
Equinix
London
UK
Email: ibagdona.ietf@gmail.com
Adam Simpson
Nokia
600 March Road
Ottawa Ontario K2K 2E6
Canada
Email: adam.1.simpson@nokia.com
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