Subject: CR-LDP - AS fld. len. limitation

From: Katta Sambasiva Rao <[email-masked]>
Date: Mon, 30 Jul 2001 16:52:17 +0530

Hi,
In CR-LDP draft, it is assumed that Autonomous System (AS) number length as
2 bytes. (Section: 4.7.3)

But work is underway in IETF, for supporting 4 octet AS number.
There is a draft in progress by IDR work group which is talking about
extending BGP to support 4 octet AS number.

I am not sure whether the 4 octet AS number support is a BGP required
feature or it is a general requirement for Internet.

If 4 octet AS number support is necessary , it is better to encode AS number
as TLV or AS number field can be declared as variable length filed which can
be extracted using length filed of ER-HOP TLV.

Regards,
Katta

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From: Eric Gray <[email-masked]>
Date: Mon, 30 Jul 2001 09:10:23 -0400

Katta,

    I am certain that - when a new size for AS numbers is defined - then
a number of protocols will need to be looked at to see if there is a need to
extend them to support this new size.  As it is, most newer protocols are
defined in such a way that it is not too hard to extned them for just such
an occasion.  CR-LDP and RSVP-TE are both extensible in this way.

    Hence, no particular change is immediately required for either of these
MPLS explicit route signaling protocols.

--
Eric Gray