[c-nsp] 7200 MPLS MTU Issues

[mikus]

Beware of mpls mtu issues across cisco platforms, especially in
6500/7600's.  Many have several ddts' for bugs, variable in 6500's
depending on the line card.  We saw issues with 67xx gige blades where
it would ignore "mpls mtu", and were forced to change mtu on the
interface to work around a bug.  In the same chassis, mpls mtu worked
fine on a 6416 gige blade.  Similiar issues on some revs of 7200/7300
routers of ignoring mpls mtu. We run 12.2.18SXD3 on all our 6500's,
and these bugs aren't set to be fixed until next month with SXE (if
they get it right the first time).

Anyways, just wanted to warn to to expect mileage to vary.  Good luck!

-mb


On Wed, 16 Mar 2005 07:36:59 -0500 (EST), Jon Lewis <jlewis at lewis.org> wrote:
> On Wed, 16 Mar 2005, Kenny Stoltz wrote:
> 
> > interface Vlan112
> >  ip address ip2 secondary
> >  ip address ip1
> >  no ip redirects
> >  tag-switching mtu 1526
> >  tag-switching ip
> > end
> >
> > (my other router is a 7600, the link into it is an ISL trunk)
> 
> Exactly what supervisor are you using in the 7600?  AFAIK, it has to be a
> sup720-3b or 3bxl for tag-switching to work.  Lower sups won't stop you
> from configuring tag-switching...but they won't work.
> 
> ----------------------------------------------------------------------
>  Jon Lewis                   |  I route
>  Senior Network Engineer     |  therefore you are
>  Atlantic Net                |
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