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?
Regards,
Jakob.
From: Sriram, Kotikalapudi (Fed) <[email protected]>
Sent: Tuesday, February 4, 2020 10:22 AM
To: Jakob Heitz (jheitz) <[email protected]>; Job Snijders <[email protected]>; Nick
Hilliard <[email protected]>; John Heasly <[email protected]>
Cc: [email protected]; [email protected]; [email protected]; [email protected];
[email protected]; Brian Dickson <[email protected]>
Subject: Question about BGP Large Communities
In the route leaks solution draft,
https://tools.ietf.org/html/draft-ietf-grow-route-leak-detection-mitigation-02
we (the authors) have proposed using BGP Large Community.
We specify this to be a "well-known transitive Large Community".
Question:
Can the draft simply make an IANA request for
a Global Administrator ASN value for Route Leaks Protection (RLP) type
and request that it be published in IANA registry
as a "well-known Transitive Large Community"?
There is no IANA registry for Large Communities yet;
we have requested IDR and GROW Chairs to facilitate that.
----------------
Details/background:
We've read the following RFCs related to Large Communities:
https://tools.ietf.org/html/rfc8092
https://tools.ietf.org/html/rfc8195
RFC 8195 has this table:
+-------------------------------+-------------------------+
| RFC8092 | RFC 8195 |
+-------------------------------+--------------------------+
| Global Administrator | ASN |
| Local Data Part 1 | Function |
| Local Data Part 2 | Parameter |
+--------------------------------+-------------------------+
which is instructive. In the examples that RFC 8195 offers,
it appears it is *assumed* that the Large Communities are transitive.
For comparison, in Extended Communities (RFC 7153), there are
explicit Type values assigned for Transitive, Non-transitive, etc.
https://www.iana.org/assignments/bgp-extended-communities/bgp-extended-communities.xhtml
However, there is no such explicit Type specification
for Large Communities (in RFC 8092 or elsewhere).
Thank you.
Sriram
IDR J. Heitz
Internet-Draft Cisco
Intended status: Standards Track February 4, 2020
Expires: August 7, 2020
BGP Well Known Large Community
draft-heitz-idr-wklc-00
Abstract
A range of BGP Autonomous System Numbers is reserved to create a set
of BGP Well Known Large Communities.
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 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 August 7, 2020.
Copyright Notice
Copyright (c) 2020 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
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
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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. Encoding . . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Transitivity . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Security Considerations . . . . . . . . . . . . . . . . . . . 3
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3
6. Normative References . . . . . . . . . . . . . . . . . . . . 4
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 4
1. Introduction
The Global Administrator field of the BGP Large community [RFC8092]
is an Autonomous System Number (ASN). To create a set of Well Known
Large Communities, a set of ASNs is required to be reserved for them,
such that a real ASN in the Global Administrator field cannot be
mistaken for a Well Known Large Community.
2. Encoding
Each BGP Well Known Large Community value is encoded as a 12-octet
quantity, 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1 1 1 1 0 1 0| T | WKLC ID | Data 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data 3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The fields are as shown below:
T - Transitivity field (2 bits). This is further
described below.
WKLC ID - Well Known Large Community Identifier (1 octet).
See IANA Considerations. If an experimental type
is used, then it MUST NOT be hard coded in the BGP
speaker software; it MUST be configurable.
Different experiments can then run in the same
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network without having to coordinate identifier
assignment during the coding stage.
Data 1,2,3 - A 10 octet value specific to the WKLC.
3. Transitivity
The transitivity field determines how BGP speakers transfer the WKLC
across real Autonomous System (AS) boundaries. The transitivity is
advisory. If a BGP speaker wishes not to receive a particular large
community, it MUST filter it out using local policy. The values are:
0 - Transitive: The WKLC is transitive across ASes.
1 - Non-transitive: The WKLC is not transitive across ASes.
2 - Administration Transitive: The WKLC is transitive across
ASes under the same administration only. By default, every
AS boundary is also an administration boundary. If an
external BGP session is configured as a non-administrative
boundary, then it will send and receive WKLCs with
transitivity 2, else it will discard the WKLC from the
UPDATE message.
3 - One-time Transitive: The WKLC is transitive across ASes
under the same administration and into an AS under the
neighboring administration, but not into an AS under a
further administration. A BGP speaker that receives a WKLC
with transitivity 3 on an external BGP session on an
administrative boundary SHOULD change the transitivity to 2.
4. Security Considerations
The BGP Large Community Path attribute is transitive. Thus a BGP
speaker that does not recognize the transitivity field may transmit
the WKLC contrary to the advisement of the transitivity field. If a
BGP speaker wishes not to receive any Large Community, it must
continue to filter it in the same way it was doing before the
transitivity field was introduced.
5. IANA Considerations
IANA is requested to assign the range 4093640704 (0xF4000000) to
4127195135 (0xF5FFFFFF) from the BGP ASN registry for BGP Well Known
Large Communities.
IANA is requested to create a registry of Well Known Large
Communities in the range 0 to 255. Numbers from this registry are to
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be assigned in accordance with the policies defined in [RFC8126].
The policies for the folowing number ranges are:
0-63 - RFC Required
64-223 - First Come First Served
224-255 - Experimental
6. Normative References
[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>.
[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>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
Author's Address
Jakob Heitz
Cisco
170 West Tasman Drive
San Jose, CA 95134
USA
Email: [email protected]
Heitz Expires August 7, 2020 [Page 4]
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