Tue, Feb 04, 2020 at 08:45:40PM +0000, Jakob Heitz (jheitz):
> A set of well known large communities could be useful.
> I have a draft that I never submitted attached to this email.
> Does anyone want to co-author and suggest changes?
Hey Jacob,
I'd work on that with you. Job, Morrow and I also started a draft for
Large WKCs, but we have not submitted anything - nor made any recent
progress.
IIRC, the direction we were intending to use 0 (zero) as the ASN, then
define local data part 1 as WKC itself, and local data part 2 to be a
value associated.
I've attached that I have written so far. Job and Morrow may or may not
endorse this approach at this point.
-heas
Global Routing Operations J. Snijders
Internet-Draft NTT Communications
Intended status: Standards Track June 4, 2019
Expires: December 6, 2019
BGP Well-known Large Communities
draft-snjiders-bgp-wk-lc-00
Abstract
This document describes well-known BGP Large Communities [RFC8092]
akin to those of BGP Communities [RFC1997].
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
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 https://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 December 6, 2019.
Copyright Notice
Copyright (c) 2019 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
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
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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. Taxonomy of Well-known BGP Large Communities . . . . . . . . 2
2.1. Well-known Global Administrator . . . . . . . . . . . . . 2
2.2. Local Data Part 1 . . . . . . . . . . . . . . . . . . . . 3
2.3. Local Data Part 2 . . . . . . . . . . . . . . . . . . . . 3
3. Well-known BGP Large Communities . . . . . . . . . . . . . . 3
3.1. Examples . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Applicable Uses . . . . . . . . . . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
7.1. Normative References . . . . . . . . . . . . . . . . . . 4
7.2. Informative References . . . . . . . . . . . . . . . . . 5
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
This document describes Well-known BGP Large Communities [RFC8092].
Well-known BGP Communities [RFC1997] have proven utility and Well-
known BGP Large Communities have supplemental benefit because their
greater capacity allows for an accompanying argument, such as a four-
octet BGP ASN [RFC6793].
Furthermore, an IANA registry is created for these new Well-known
Communities.
2. Taxonomy of Well-known BGP Large Communities
BGP Large Communities [RFC8092] are entities of three four-octet
values known as the Global Administrator, and Local Data Part 1 and
2. The use of each is defined below.
2.1. Well-known Global Administrator
The Global Administrator (GA), or namespace identifier, is the BGP
Autonomous System Number (ASN) that defined the significance of the
subsequent Local Data Parts. Because ASN 0 is otherwise proscribed
from use by [RFC7607] and discouraged by [RFC8092], it is opportune
for prescription as the Well-known Community namespace identifier in
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the GA field, and this document reserves it for this purpose. It is
also an easily typed and obvious value for operator convenience.
One might be inclined to suggest the use of 65535 or 4294967295
([RFC7300]), which are also taboo. An Private Use ASN [RFC6996] or
23456 (AS_TRANS, [RFC4893]) might also come to mind. The authors
feel that zero is more convenient than the first two and avoids
conflict within an AS that might use the latter ASNs.
2.2. Local Data Part 1
This, the second field, is the Well-known Community value itself. In
the parlance of [RFC8092], it is the function by which Local Data
Part 2 is evaluated.
2.3. Local Data Part 2
This, the third field, is the argument of or to the Well-known
Community.
3. Well-known BGP Large Communities
This document defines the following Well-known BGP Large Communities,
further described below. In all cases, the Global Administrator is
zero.
+-------------------+-------------------+-------------------------+
| Local Data Part 1 | Local Data Part 2 | description |
+-------------------+-------------------+-------------------------+
| 0 | ASN | no-export from AS ASN |
+-------------------+-------------------+-------------------------+
| 1 | ASN | do not export to AS ASN |
+-------------------+-------------------+-------------------------+
Table 1: Well-known BGP Large Communities
3.1. Examples
+---------------+---------------------------+
| Community | description |
+---------------+---------------------------+
| 0:0:64496 | no-export from AS 64496 |
+---------------+---------------------------+
| 0:1:65551 | do not export to AS 65551 |
+---------------+---------------------------+
Table 2: Well-known BGP Large Community Examples
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4. Applicable Uses
Well-known BGP Large Communities are not intended to replace Well-
known BGP Communities [RFC1997], nor well-known communities of other
BGP community types that may evolve. Use the correct tool for the
problem. By example, a routing policy concept that requires an
argument that can be represented in 4-octets is appropriate, while
replicating the [RFC1997] NO_EXPORT community would not.
5. Security Considerations
This document does not change any existing security issues associated
with BGP Large Communities nor of other BGP Community Attributes. In
addition to the considerations expressed in [RFC8092], an Autonomous
System (AS) that accepts, sends or forwards NLRI with Well-known BGP
Large Communities must itself be aware of how these communities will
implicitly or explicitly affect route selection.
6. IANA Considerations
IANA is requested to create a new registry for Well-known BGP Large
Communities [RFC8092] by the name "BGP Well-known Large Communities".
The registry MUST have two fields, Local Data Part 1 and Local Data
Part 2, and MUST be seeded with the values defined by this document
in Table 1 of Section 3.
The allocation policy for new entries is first come, first served for
Local Data Part 1 values of 0 through 2147483647 (0 - 0x7fffffff) and
"Standards Action" for 2147483648 through 4294967295 (0x80000000 -
0xffffffff).
The Local Data Part 2 is an argument associated with a particular
Local Data Part 1, whose value can be unspecified (any value), a
single or range of values, or have an allocation policy set forth by
a separate "Standards Action."
Allocation of a large swath of Local Data Part 1 values to a single
function or concept is NOT RECOMMENDED. Non-consecutive Allocation
is NOT RECOMMENDED.
7. References
7.1. Normative References
[RFC1997] Chandra, R., Traina, P., and T. Li, "BGP Communities
Attribute", RFC 1997, DOI 10.17487/RFC1997, August 1996,
<https://www.rfc-editor.org/info/rfc1997>.
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[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC4893] Vohra, Q. and E. Chen, "BGP Support for Four-octet AS
Number Space", RFC 4893, DOI 10.17487/RFC4893, May 2007,
<https://www.rfc-editor.org/info/rfc4893>.
[RFC6793] Vohra, Q. and E. Chen, "BGP Support for Four-Octet
Autonomous System (AS) Number Space", RFC 6793,
DOI 10.17487/RFC6793, December 2012,
<https://www.rfc-editor.org/info/rfc6793>.
[RFC6996] Mitchell, J., "Autonomous System (AS) Reservation for
Private Use", BCP 6, RFC 6996, DOI 10.17487/RFC6996, July
2013, <https://www.rfc-editor.org/info/rfc6996>.
[RFC7300] Haas, J. and J. Mitchell, "Reservation of Last Autonomous
System (AS) Numbers", BCP 6, RFC 7300,
DOI 10.17487/RFC7300, July 2014,
<https://www.rfc-editor.org/info/rfc7300>.
[RFC7607] Kumari, W., Bush, R., Schiller, H., and K. Patel,
"Codification of AS 0 Processing", RFC 7607,
DOI 10.17487/RFC7607, August 2015,
<https://www.rfc-editor.org/info/rfc7607>.
[RFC8092] Heitz, J., Ed., Snijders, J., Ed., Patel, K., Bagdonas,
I., and N. Hilliard, "BGP Large Communities Attribute",
RFC 8092, DOI 10.17487/RFC8092, February 2017,
<https://www.rfc-editor.org/info/rfc8092>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
7.2. Informative References
[RFC8195] Snijders, J., Heasley, J., and M. Schmidt, "Use of BGP
Large Communities", RFC 8195, DOI 10.17487/RFC8195, June
2017, <https://www.rfc-editor.org/info/rfc8195>.
Author's Address
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Job Snijders
NTT Communications
Theodorus Majofskistraat 100
Amsterdam 1065 SZ
The Netherlands
Email: [email protected]
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