From: barrerj1@hotmail.com
Date: Sat Jul 03 2004 - 13:45:42 GMT-3
Ok.
I get it
Thanks to all
JB
-----Original Message-----
From: Shibu Nair [mailto:shinair@cisco.com]
Sent: Saturday, July 03, 2004 10:37 AM
To: barrerj1@hotmail.com
Cc: ccielab@groupstudy.com
Subject: Re: OSPF MTU problem
I think you are using VLAN interface as the L3 interface on the switch
side.
When you use the vlan interface on the switchside, MTU size is little
more than 1500.
So manual setup the mtu as the same on both sides or "ip ospf
mtu-ignore" interface
command should solve the issue.
Try out
Regards
Shibu
At 06:26 AM 7/3/2004 -0500, barrerj1@hotmail.com wrote:
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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