Re: draft-ietf-l3vpn-as4octet-ext-community-00.txt

[Yakov Rekhter <[e-mail]>]

Bruno,

> Yakov, Srihari, Dan,
> 
> >From RFC 4893 (BGP Support for Four-octet AS Number Space): "Currently
> assigned 2-octet Autonomous System numbers are converted into 4-octet
> Autonomous System numbers by setting the two high-order octets of the
> 4-octet field to zero.  Such a 4-octet AS number is said to be mappable
> to a 2-octet AS number."
> 
> So it seems that a 2-octet Autonomous System would have two ways to
> encode a Route Target or Route Origin:
> - using a two-Octet AS Specific Extended Community as defined in rfc4360
> (BGP Extended Communities Attribute)
> - using a four-octet AS specific extended community as described in
> draft-ietf-l3vpn-as4octet-ext-community-00.txt
> 
> It looks to me this could create interop issue for BGP/MPLS VPN, even
> within a 2 octet AS.
> 
> IINM, may I suggest that you add a sentence in the draft to handle such
> case? (e.g., mandating the use of *Two*-Octet AS Specific Extended
> Community, reserving the "mappable to a 2-octet" AS numbers, ...).

That seems reasonable. Could you propose the text.

Yakov.