Subject: mtu in DD exchange.

From: prashant desai <[email-masked]>
Date: Thu, 20 Jun 2002 10:45:44 -0700

Hi,
Can anyone give me a good reason why OSPF routers have to agree on
the MTU size during DD exchange process..
As OSPF runs over IP..fragmentation or reassembly should not be its
concern..and they will be transparently handled by the IP layer..

Prashant

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From: Daniel Gryniewicz <[email-masked]>
Date: Thu, 20 Jun 2002 13:59:07 -0400

What fragments?  All OSPF (baring virtual links) traffic is only on one link. 
What the MTU agreement assures is that everyone on the link agrees what the
MTU *for that link* should be.  If I think the MTU is 9000, and you think the
MTU is 1500, you'll silently drop all my packets.  My IP layer won't fragment,
because it thinks the MTU is large enough.

Daniel

On Thu, 20 Jun 2002 10:45:44 -0700

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From: Alex Zinin <[email-masked]>
Date: Thu, 20 Jun 2002 12:38:02 -0700

Prashant,

http://www.ietf.org/ietf/ospf/ospf-minutes-96dec.txt

--
Alex