[c-nsp] q-in-q mtu

[Tony]

--- On Fri, 22/10/10, Chris Wopat <me at falz.net> wrote:

> > On Thu, 21 Oct 2010, Daniel
> Hooper wrote:
> >
> > The 7206 doesn't accept anything higher than 1500 on
> that interface.
> 
> Some 12.2S trains allow you to up the MTU on 7200 to 1530.
> I'm
> currently running SB, I'm unsure if SR* can do it or not.
> 
> http://puck.nether.net/pipermail/cisco-nsp/2007-March/039033.html


We're running 12.2(33)SRD1 on 7204 with NPE-300.

The Fa0/0 port on the I/O controller (C7200-I/O-2FE/E) supports larger MTU (1530 is the max):

interface FastEthernet0/0
 mtu 1530
 no ip address

We're then running an IP MTU of 1524 on the subinterface that runs MPLS:

interface FastEthernet0/0.3
 encapsulation dot1Q 3
 ip mtu 1524
 mpls ip


The same setup works on the PA-FE-TX cards in these boxes and also worked on SRC.


regards,
Tony Miles.