[c-nsp] Show system jumbomtu

[Sukumar Subburayan]

  Global System MTU can be used for dropping packets on the 
egress.

For eg, if the 'system jumbomtu.. ' is set at 5000 byte,s this will
make all switchports with 'mtu 9216' to drop packets above 5000 bytes on 
the egress, regardless of the individual port mtu configuration.

L2/L3 physical Interface MTU (mtu <mtu-size>) is used to enable jumbo 
frame support on the physical interfaces for L2 or L3.

SVI MTU again can be used to enable L3 Jumbo frame support for that 
Switch Virtual Interface (SVI).

There is no need to touch 'vlan MTU' in the vlan config mode to support 
Jumbo frames.

When you enable L3 Jumbo frame support on L3 ports (L3 physical port or 
SVI), it automatically adjusts 'ip mtu..' . The reverse is not true.

I don't know about MPLS MTU stuff. Someone else can chime in.

How you want to use all this depends on what you want to do.


sukumar

On Fri, 30 Mar 2007, Alaerte.Vidali at nokia.com wrote:

> Thank you.
>
> Would you indicate good documentation public available that explains if
> when using system MTU it is still necessary use interface MTU?
> (or not)
>
> And shows the relation between:
> Vlan MTU
> System MTU
> MPLS MTU
> Interface MTU
>
> I read documents I found in Cisco page, and applied it on 7600. The
> result I got is that only system MTU was not enough. It was necessary
> configure interface MTU.
>
>
> Regards,
> Alaerte
>
> -----Original Message-----
> From: ext Sukumar Subburayan [mailto:sukumars at cisco.com]
> Sent: Friday, March 30, 2007 3:27 PM
> To: Vidali Alaerte (Nokia-NET/RioDeJaneiro)
> Cc: cisco-nsp at puck.nether.net
> Subject: Re: [c-nsp] Show system jumbomtu
>
> We had supported 'show system mtu' cli only on the cat4k.
>
> On the 6k, since the configured system MTU can be viewed in the running
> config, it command to show the value was not added.
>
> we never got to implement 'show system jumbomtu'.
>
> Please refer to CSCdy28580
>
> sukumar
>
>
>
>
> On Fri, 30 Mar 2007, Alaerte.Vidali at nokia.com wrote:
>
>> Do you know if there is any hidden issue with this command?
>>
>> I tried it in 2 IOS versions it was supposed to work, but no support.
>>
>> Version 12.2(33)SRA1
>>
>> OSR-1#show system ?
>> % Unrecognized command
>> OSR-1#show system
>>
>> Version 12.2(17d)SXB7
>> OSR-2#sh system?
>> % Unrecognized command
>> OSR-2#sh system
>>
>>
>>
>> Tks,
>> Alaerte
>>
>> _______________________________________________
>> cisco-nsp mailing list  cisco-nsp at puck.nether.net
>> https://puck.nether.net/mailman/listinfo/cisco-nsp
>> archive at http://puck.nether.net/pipermail/cisco-nsp/
>>
>