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

Zhuangshunwan <> Wed, 05 February 2020 09:01 UTC

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From: Zhuangshunwan <>
To: Brian Dickson <>, "Dongjie (Jimmy)" <>
CC: "" <>, "" <>, "" <>, "" <>
Thread-Topic: [GROW] Question about BGP Large Communities
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Date: Wed, 05 Feb 2020 09:00:35 +0000
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Subject: Re: [Idr] [GROW] Question about BGP Large Communities
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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.

Best regards,

From: GROW [] On Behalf Of Brian Dickson
Sent: Wednesday, February 5, 2020 9:45 AM
To: Dongjie (Jimmy) <>
Subject: Re: [GROW] Question about BGP Large Communities

Disagree, we want something deployed (large) and deployable (requiring only IANA action, no vendor activity) immediately.
IMHO, any special handling or new code points or upgrades are non-starters.
This particularly applies to wide and extended

On Tue, Feb 4, 2020 at 5:41 PM Dongjie (Jimmy) <<>> wrote:
Agree that for this case it may be more convenient to just use extended community with a new type, this could avoid any possible collision with existing deployments, and save the effort of assigning a set of ASNs. Wide community may be too powerful for this:)

Best regards,

From: Robert Raszuk [<>]
Sent: Wednesday, February 5, 2020 6:38 AM
To: Jakob Heitz (jheitz) <<>>
Cc: Sriram, Kotikalapudi (Fed) <<>>; Job Snijders <<>>; Nick Hilliard <<>>; John Heasly <<>>;<>;<>;<>;<>
Subject: Re: [GROW] Question about BGP Large Communities

> How would you divide the numbers?

I would not divide them at all in LCs. I would either define new type in extended communities or use wide communities.

But I am a bit biased here ;-)


On Tue, Feb 4, 2020 at 11:34 PM Jakob Heitz (jheitz) <<>> wrote:
The numbers are a trade off. How would you divide the numbers?

On Feb 4, 2020, at 2:19 PM, Robert Raszuk <<>> wrote:

And you think 255 such known large communities will be sufficient ?


On Tue, Feb 4, 2020 at 9:45 PM Jakob Heitz (jheitz) <<>> wrote:
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?


From: Sriram, Kotikalapudi (Fed) <<>>
Sent: Tuesday, February 4, 2020 10:22 AM
To: Jakob Heitz (jheitz) <<>>; Job Snijders <<>>; Nick Hilliard <<>>; John Heasly <<>>
Cc:<>;<>;<>;<>;<>; Brian Dickson <<>>
Subject: Question about BGP Large Communities

In the route leaks solution draft,

we (the authors) have proposed using BGP Large Community.

We specify this to be a "well-known transitive Large Community".


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.



We've read the following RFCs related to Large Communities:

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.

However, there is no such explicit Type specification

for Large Communities (in RFC 8092 or elsewhere).

Thank you.


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