From: Nigel.Johnson@barclayscapital.com
Date: Sat Jul 03 2004 - 09:40:34 GMT-3
Check that you haven't changed the 'system mtu' on one of the 3550's. This
will appear towards the top of the running config.
Cheers,
Nigel
CCIE# 13514
-----Original Message-----
From: samccie2004@yahoo.co.uk [mailto:samccie2004@yahoo.co.uk]
Sent: 03 July 2004 13:07
To: barrerj1@hotmail.com; ccielab@groupstudy.com
Subject: RE: OSPF MTU problem
Are iu trunking , if so u might be adding more to MTU due to dot1q.
Just a guess, pls correct me if I am wrong.
Sam
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
barrerj1@hotmail.com
Sent: 03 July 2004 13:26
To: ccielab@groupstudy.com
Subject: OSPF MTU problem
Hi all!
While doing an OSPF practice lab, I was encountered by the following
problem.
2 routers connected to a 3550 and running OSPF between them, the state was
stuck in EXSTART and couldn't complete the adjacency.
I checked CCO and found that the problem was an MTU mismatched. However, the
CCO doc points this problem to be a common when you connect to another
vendor's router. In my case all devices are CISCO.
Neighbors Stuck in Exstart/Exchange State
The problem occurs most frequently when attempting to run OSPF between a
Cisco router and another vendor's router. The problem occurs when the
maximum transmission unit (MTU) settings for neighboring router interfaces
don't match. If the router with the higher MTU sends a packet larger that
the MTU set on the neighboring router, the neighboring router ignores the
packet.
http://www.cisco.com/en/US/tech/tk365/tk480/technologies_tech_note09186a
0080093f0d.shtml
Can any one explain why this behavior as I did not change any of the MTU
configurations before the problem occurred?
Thanks
JB
This archive was generated by hypermail 2.1.4 : Sun Aug 01 2004 - 10:11:46 GMT-3