Re: [Idr] WG LC on draft-ietf-idr-large-community-03.txt (10/17/2016 to 10/31/2016)

[t.petch <[e-mail]>]

Jared

As Brian has pointed out, it was the use of 'usually' that I was
concerned with, as watering down the recommended use of an ASN by
RFC1997.  Excise 'usually' and that part of my concern goes away.

Tom Petch


----- Original Message -----
From: "Jared Mauch" <[e-mail]>
Sent: Wednesday, October 19, 2016 7:54 PM


> On Wed, Oct 19, 2016 at 11:47:05AM +0100, t.petch wrote:
> > I remain unhappy with this I-D.
> >
> > I find it ironic that the messages for this Last Call should be
> > interspersed with those relating to what goes wrong when someone
> > somewhere else in the world uses a field in an unexpected way.  This
> > reinforces my belief that this I-D should be more forceful in
calling
> > out the dangers (eg MUST instead of SHOULD).
> >
> > I think that this I-D is factually incorrect, or at least open to
> > misinterpretation,  when it says
> > '[RFC1997] BGP Communities attributes are four-octet values split
into
> >    two two-octet words.  The most significant word is usually
> >    interpreted as an Autonomous System Number (ASN) '
>
> rfc1998: section 4 gives you the slice + dice bits:
>
> -- snip -- rfc 1998 --
>    To make use of the BGP community attribute, several community
values
>    (MCI's AS number: 3561 = 0x0DE9) have been defined that can be used
>    by customers to tag routes so that the appropriate "LOCAL_PREF"
>    values are configured. Table 2 lists the appropriate community
>    attribute values (and the mappings of community to LOCAL_PREF):
> -- snip -- rfc 1998 --
>
> This is the segmenting, and most customers have
> "ip bgp community new-format" configured.
>
> If your issue is about printf %ull vs %d:%d:%d we operators
> can solve this by ensuring our vendors do the right thing, which
> we have already done 20 years ago via rfc1998.
>
> This nit is imo not worth picking.
>
> - Jared
>
> --
> Jared Mauch  | pgp key available via finger from [e-mail]
> clue++;      | http://puck.nether.net/~jared/  My statements are only
mine.