From: barrerj1@hotmail.com
Date: Sat Jul 03 2004 - 10:37:40 GMT-3
Thanks for your reply guys!
I did not changed the system MTU
I don't' see it at the top of the config
The rack I'm using is from a rental place.
SW1#sh run
Building configuration...
Current configuration : 3309 bytes
!
version 12.1
no service pad
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname SW1
!
enable password cisco
!
ip subnet-zero
ip routing
ip rcmd rsh-enable
ip rcmd remote-host R6 140.1.6.6 R6 enable
!
no ip domain-lookup
ip ssh time-out 120
ip ssh authentication-retries 3
!
spanning-tree mode pvst
spanning-tree extend system-id
!
!
!
****************************
I'm doing dot1q trunking between the Switches, but the interfaces in
play are directly connected to the Sw1
So If I did not changed the MTU they why the OSPF is bitching about
incorrect OSPF MTU when I do a debug ip routing
Thanks
JB
-----Original Message-----
From: Nigel.Johnson@barclayscapital.com
[mailto:Nigel.Johnson@barclayscapital.com]
Sent: Saturday, July 03, 2004 7:41 AM
To: barrerj1@hotmail.com; ccielab@groupstudy.com
Subject: RE: OSPF MTU problem
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
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