[j-nsp] EX4200 MPLS Label Stacks

[Matthew Walster]

I'm aware that the Juniper EX4200 can do MPLS - indeed, I've used it
with RSVP signalled LSPs using CCC encapsulation. It's been made clear
to me that the EX series can only operate on 1 label, which completely
rules out most MPLS scenarios such as Fast Reroute, Martini/Kompella
L2VPNs, VPLS etc, leaving it just with the CCC capabilities, with
extreme loose possibilities of LDP support in the distant future.

What I'm interested in is if the EX4200 can be used as a P router,
just for RSVP LSPs, regardless of how many labels there are. That is,
if an MPLS encapsulated packet comes in with two labels, providing the
operation RSVP calls for is only a swap on the outer label, will that
work? Presumably as the inner labels are not touched/inspected except
for the L2 checksum, so it *should* work?

The scenario I'm envisioning is that the two XFP slots can act as a
"pass-through" and the 48 ports act as an MPLS CCC injector at a POP,
saving the necessity to use large amounts of rack space and cash on
MX80/240s when the EX4200 should cope.

Kind regards,



Matthew Walster