[c-nsp] EoMPLS terminating on PE?

[Marko Milivojevic]

I don't think that routed pseudowire would work for you, but I could
be mistaken. However, external loop may work. If I understand your
problem well, this is what you want (horrible ascii art follows):

[CE]---{ATM PVC}--->[PE]---[P]---[PE]
                   |              >{L3}
                   |              |
                   +---xconnect---+

If I understood that correctly, and you are willing to play with
external loopbacks (since you own 7600, you definitely are, btw.) read
on.

> Most definitely one-off, but what kind of loop cable would that be ? An ATM one?

Yes, you can loop, for example ATM3/0/0 to ATM3/0/1 on rightmost PE.
Have xconnect from 3/0/0 to leftmost PE and L3 interface on 3/0/1. If
you have available and unused ATM interfaces, this is the easiest
thing to do. It's a little bit expensive, IMHO.

> I'm thinking that I could terminate the aal5snap pvc into a VLAN on
> some convenient third PE router, and then run a straight 802.1q into
> the PE router I want the termination on, but mightn't there be some
> kind of encapsulation problem? All the examples I've seen do xconnects
> between VLANs or between PVCs, not between a VLAN on one hand and a
> PVC on the other hand.

This could be on the right track, though. I'm not entirely sure about
support on 7600, but you could have xconnect between ATM and 802.1Q
interface using IP interworking.

Another approach, without 3rd party router would be to loop two
GigabitEthernet inerfaces on rightmost PE using an external cable and
do exactly the same thing as described with ATM loopback above. You
would xconnect from one and have L3 on the other one. Note that if you
are using LAN cards for this excercise, you will need to configure
VLAN mapping, as VLAN's are global. It's still a little bit cheaper
than using ATM interfaces, albeit messier.

> (Anxiously waiting to see if anyone has insights on my service provider network design
> question from a few days ago, no one's taken me up so far ;-))

( it was a little bit unclear :-) )

HTH.

--
Marko
CCIE #18427
My network blog: http://cisco.markom.info/