Re: [Idr] Review of draft-ietf-large-community-06

Job Snijders <> Tue, 08 November 2016 11:26 UTC

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Date: Tue, 8 Nov 2016 12:26:16 +0100
From: Job Snijders <>
To: Mach Chen <>
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Subject: Re: [Idr] Review of draft-ietf-large-community-06
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On Tue, Nov 08, 2016 at 06:22:54AM +0000, Mach Chen wrote:
> I have review the latest version(06) of this document. The draft is
> well written and is basically ready for publication. I have some minor
> comments as bellows:
> 1. 
> Section 2, the first sentence:
> "This document creates the Large BGP Communities attribute as an..."
> Although RFC1997 also uses "creates", I'd suggest to use "defines"
> here, it also aligns with the convention of most of the RFCs.

Good suggestion, accepted.

> 2.
> Section 2, the last sentence:
> "A receiving speaker SHOULD silently remove duplicate Large BGP
> Communities from a BGP UPDATE message."
> IMHO, whether remove the duplicate communities from a BGP UPDATE
> message is not significant, since the life of the message is over once
> the message processed. The key point is that the receiving speaker
> should ignore the duplicate Large BGP Communities. 
> How about:
> "A receiving speaker SHOULD silently ignore the duplicate Large BGP
>    Communities within a Large BGP Communities attribute. "

After the latest round of review from Geoff Huston and Jakob Heitz the
following text was produced.

The below text is queued to be in -07 of the draft, but -07 can't be
posted yet as we are in the 'cutoff' period before the IETF meeting in

	Duplicate BGP Large Community values SHOULD NOT be transmitted. A
	receiving speaker SHOULD silently remove duplicate BGP Large
	Community values from a BGP Large Community attribute.

I think the above text aligns with your suggestion, right?

> 3.
> In Section 5 says:
>    "Operators SHOULD NOT use these Global Administrator values."
> Later, in Section 6:
> "The Large BGP Communities Global Administrator field may contain any
> value, and a Large BGP Communities attribute MUST NOT be considered
> malformed if the Global Administrator field contains an unallocated,
> unassigned or reserved ASN or is set to one of the reserved Large BGP
> Community values defined in Section 5."
> The "SHOULD NOT", "may contain any value" and "MUST NOT" seems little
> bit confusion and self-contradiction. Since the first sentence is not
> a specification to the Large BGP Communities attribute, but just a
> recommendation to the Operators.
> How about changing it as:
> "It is recommended that operators do not use these Global
> Administrator values." 
> Or using some other similar text.

I don't see the contradiction, its text that gradually narrows down into
specifics for specific audiences. The text in section 5 is for
operators, the text in section 6 is for implementors and bgp developers.
I don't think that removing the 2119 language will increase the clarity.

> Hope this comments helps!

Very much appreciated!

Kind regards,