Subject: router LSA with unknown link type

From: "Field, Brian" <[email-masked]>
Date: Tue, 23 Nov 2004 20:47:19 -0700

If a router receives a router LSA that contains several links and
for one of the links, the link type field is not known, should the
router ignore the entire router LSA or just skip this one link?

Thanks
Brian

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From: Acee Lindem <[email-masked]>
Date: Wed, 24 Nov 2004 11:06:44 -0500

>router ignore the entire router LSA or just skip this one link?
Hi Brian,
Unfortunately, the handling of unknown link types is not specifically
defined in RFC 2328.
Since links types 1-4 are the only ones defined an implementation should
probably log
the invalid link type (with rate limiting). Whether it ignores the LSA
or just the unknown link is
implementation specific. If we were to move forward with link type
extension it would not be
backward compatible (at least not without knobs or other mechanisms).

Thanks,
Acee

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From: Nitin Kakkar <[email-masked]>
Date: Thu, 25 Nov 2004 16:21:33 +0530

IMHO I can think of two possibilities for this condition

1) Some error in LSA creation, which overwrite link type field. : This
should be reflected in checksum error and should be handled such.

2) Some new invension which adds to the existing 4 types of Link Types (or
support for unknown link types): This Needs to have some common
understanding (RFC etc) to handle this. I feel that they can be handled like
unknwon LSA's (store & forward only, no routing calc's)

HTH
Nitin

-----Original Message-----
From: Mailing List [mailto:[email-masked]]On Behalf Of Acee
Lindem
Sent: 2004Ae11OA24EO 21:37
To: [email-masked]
Subject: Re: router LSA with unknown link type

Hi Brian,

Thanks,
Acee

---

From: Acee Lindem <[email-masked]>
Date: Thu, 25 Nov 2004 12:13:39 -0500

All,
While it would have been better if RFC 2328 did precisely specify what
to do with unknown link types the fact of the matter is that it doesn't.
IMHO,
we'd need a short draft in order to formally specify this (or concensus
and inclusion
in the RFC 2740 respin). At this point, the implementation(s) that
generate(s)
the unknown link types is/are the ones in violation of the protocol.

Speaking as a WG member, I really don't like the idea of extending the
protocol
using unknown link types UNLESS the new types are in fact a different
type of
intra-area topological edge in the SPF graph. Once we open it up I can
envision people
trying to cram all sorts of non-link data in the router LSA. If we want
to extend the
protocol past what it does today there are cleaner ways of doing it
(e.g., new LSA types
supporting TLVs).

Thanks,
Acee