Re: [Idr] BGP Attribute for Large communities (Attribute 30) was squatted on - Let's get a new attribute number (1 week WG call (10/18 to 10/25)

"Jakob Heitz (jheitz)" <> Tue, 25 October 2016 22:27 UTC

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From: "Jakob Heitz (jheitz)" <>
To: Susan Hares <>, "" <>
Thread-Topic: [Idr] BGP Attribute for Large communities (Attribute 30) was squatted on - Let's get a new attribute number (1 week WG call (10/18 to 10/25)
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Date: Tue, 25 Oct 2016 22:27:17 +0000
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Subject: Re: [Idr] BGP Attribute for Large communities (Attribute 30) was squatted on - Let's get a new attribute number (1 week WG call (10/18 to 10/25)
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I have discovered that Cisco has used BGP attribute code 31
for an internal experiment in certain NXOS routers,
but unfortunately some of the code leaked into production.
The code does not send the attribute,
but it receives it incorrectly. We are creating patches for the
faulty code, but cannot guarantee that all affected routers will
be patched. Consequently, we request deprecation of attribute
code 31 as well.

I apologize on behalf of Cisco for the oversight.


From: Idr [] On Behalf Of Susan Hares
Sent: Monday, October 24, 2016 5:19 AM
Subject: [Idr] BGP Attribute for Large communities (Attribute 30) was squatted on - Let's get a new attribute number (1 week WG call (10/18 to 10/25)

IDR Working group:

Thank you for your input on the question of whether Large communities should be reassigned another attribute number due to Huawei squatting on attribute 30.  The WG consensus is that the IDR WG wishes to have IANA deprecate attribute 30, and reassign large communities another attribute number for its early allocation.

Alvaro should request a new attribute number for wide communities.

If wide communities implementers request an early allocation, the WG consensus was unclear.  Therefore,  the code point of 129 is deprecated for now.  The full discussion on this point is at:

The following other attributes were seen in the wild with the comments we saw:

#        BGP function                                      Reference
----    -----------------------------------------------   ---------------
20     Connector Attribute (deprecated)   [RFC6037]
21      AS_PATHLIMIT (deprecated)           [draft-ietf-idr-as-pathlimit, unknown]
30     (deprecated)                                       [variant of draft-ietf-tunnel-encaps, Huawei router]
129   (deprecated)                                       [draft-ietf-idr-wide-bgp-communities, Huawei router]

Attribute  AS Attribute Observed
-----------   --------------------------------
20           AS 22742  (Peter Hessler)
21           AS 14706, AS 11720, AS 22490

30   -  in trials reported by Job
129 -  self-reported by Huawei

Sue Hares