[c-nsp] GRE/MPLS

[Tim Franklin]

Hi Tim,

On Tue, June 24, 2008 10:30 am, Timothy Arnold wrote:

> PE1/PE2 are 7600s with RSP-720s running 12.2(33)SRC. CPEs are 1841s with
> 12.4(19b) and the advanced IP services feature pack.
>
> The CPE has a static default towards PE1 via the GRE tunnel. It has
> another route via the FE interface to the GRE tunnel destination

Is the FE interface with the tunnel destination *just* running vanilla IP,
or also label-switching?

I've previously had to split out a physical interface into a
label-switched and an IP-only sub-interface, together with some magic
around /32 routes to force GRE tunnels onto their own sub-interface -
without this, the router was refusing to apply a label to packets coming
out of the tunnel.

(Sorry, a fair while ago and in another life, so I don't have details of
platform / code).

> The CPE can access other hosts on PE1 so the routing to/from the CPE must
> be OK?  E.g.
>
> 1 172.31.255.45 164 msec 164 msec 8 msec
> 2 172.31.255.18 20 msec 24 msec 16 msec
> 3 10.201.0.13 20 msec 20 msec 20 msec
> 4 10.201.8.2 20 msec *  24 msec
>
> To any host on other PE routers
>
> 1 172.31.255.45 12 msec 212 msec 152 msec
> 2  *  *  *

This definitely sounds label-related - 'regular' routing works, but
anything requiring label imposition doesn't.

Regards,
Tim.