From: Richard Gallagher (rgallagh@cisco.com)
Date: Sat Jul 03 2004 - 12:39:45 GMT-3
BTW on your rental rack, the MTU has been changed on the switch. The
default is 1500:
http://www.cisco.com/univercd/cc/td/doc/product/lan/c3550/12114ea1/3550cr/cli2.htm#2423299
Rich
On Sat, 2004-07-03 at 17:36, Shibu Nair wrote:
> 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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