Subject: [GROW] Missing things in the current MRT draft

From: Ondrej Zajicek <[email-masked]>
Date: Mon, 28 Dec 2009 15:57:28 +0100

Hello

I am implementing MRT dump feature in BIRD Internet Routing Daemon [1]
(for BGP protocol) and i found that current MRT draft
draft-ietf-grow-mrt-10.txt [2] does not contain enough semantic
information for some datafields that is needed for an interoperable
implementation.

These problems i found in the description of MGP4MP message type:

 - Fields Local/Peer IP address (and even Peer AS number) may
   be sometimes undefined (if there is no open TCP connection, for
   example in BGP4MP_STATE_CHANGE generated by Idle -> Active state
   change). It would be nice to mention in the draft that these fields
   may be also zero if the values are unknown/undefined.

 - The IP address / AS number fields are marked as Peer / Local,
   but bgpdump tool shows them as From / To. Is there an implicit
   assumption that only received (and not sent) BGP messages are
   dumped?

 - The most important question is whether difference in BGP4MP_MESSAGE
   and BGP4MP_MESSAGE_AS4 is just in MRT message header format, or if it
   is also semantic information whether these BGP messages were received
   in 'AS4-style' session or 'old' session (and therefore whether
   AS_PATH attribute in UPDATE messages contains 2B or 4B AS numbers).

[1] http://bird.network.cz

[2] http://www.ietf.org/id/draft-ietf-grow-mrt-10.txt

-- 
Ondrej 'SanTiago' Zajicek (email: [email-masked])
OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net)
"To err is human -- to blame it on a computer is even more so."