Re: [Idr] [GROW] Question about BGP Large Communities

Nick Hilliard <> Wed, 05 February 2020 10:15 UTC

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To: Zhuangshunwan <>
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From: Nick Hilliard <>
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Date: Wed, 05 Feb 2020 10:14:52 +0000
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Subject: Re: [Idr] [GROW] Question about BGP Large Communities
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Zhuangshunwan wrote on 05/02/2020 09:00:
> In my opinion, when we apply a new function from IANA, we will have to 
> deploy some extra route policies to set and parse the specific function 
> as your suggested way.
> With the increase of new functions, the route policies deployed will 
> become more and more complicated.

A WKC will generally describe a specific function or set of actions to 
be applied to a prefix. If the WKC also encodes an administrator ASN or 
a target ASN, then it becomes a domain-specific community rather than a 
well-known community.

I'm not against the idea of LC WKCs in theory, but there would need to 
be compelling reasons as to why the existing rfc1997 wkc range didn't 
work.  IOW, we should think twice about setting aside a range unless 
there are specific deployment cases which need LCs, and where rfc 1997 
communities wouldn't work.