Re: System MTU question

yes Ryan... its correct. Its under interface.

On Sun, Oct 18, 2009 at 2:38 PM, Ryan West <rwest_at_zyedge.com> wrote:

> Justin,
>
> That's normal, probably a left over system mtu from QinQ configuration.
> You do have the option of setting of system mtu routing 1500 as a
> workaround for the 3560 and above series. You can also tell the OSPF
> process to ignore the MTU on a per-interface basis. Ip ospf mtu-ignore (I
> think).
>
> -ryan
>
> -----Original Message-----
> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
> Justin Mitchell
> Sent: Sunday, October 18, 2009 7:35 AM
> To: Cisco certification
> Subject: System MTU question
>
> I am working on an OSPF configuration and watching the console
> messages long enough I get to see one neighbor go up and down with the
> message:
>
> R3#
> *Nov 7 21:13:10.955: %OSPF-5-ADJCHG: Process 1, Nbr 112.12.108.1 on
> FastEthernet0/0 from EXSTART to DOWN, Neighbor Down: Too many
> retransmissions
> R3#
> *Nov 7 21:14:10.955: %OSPF-5-ADJCHG: Process 1, Nbr 112.12.108.1 on
> FastEthernet0/0 from DOWN to DOWN, Neighbor Down: Ignore timer expired
>
> So I issue "debug ip ospf ev" and get the notice the following:
>
> *Nov 7 21:11:12.815: OSPF: Rcv DBD from 112.12.108.1 on
> FastEthernet0/0 seq 0x12A6 opt 0x52 flag 0x7 len 32 mtu 1504 state
> EXSTART
> *Nov 7 21:11:12.815: OSPF: Nbr 112.12.108.1 has larger interface MTU
>
> I changed to the switch causing the problem and set "system mtu 1500"
> reloaded and then the adjacency forms without any problems.
>
> Is this normal? I usually don't set the MTU unless required for
> overhead reasons.
>
> Justin G. Mitchell
> http://www.google.com/profiles/jgmitchell
>
>
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Received on Sun Oct 18 2009 - 14:45:40 ART