What's the role of P in Frame-mode MPLS

[Harold Ritter]

Conceptually speaking, the P router forwards packet solely based on the label information. So still from a theorical perspective, it doesn't need the whole Internet routing table.

Is that what your question was about?

[melkomy]

The MPLS/VPN model can be running on 2 directly connected PEs routers ( on more precisely 2 E-LSRs ) without any LSR/P routers connecting them.

I've implemented such a LAB and there were no problems with MPLS-VPN connectivty across the PEs.

So does that mean that there can be no need for the P in Frame mode MLA environment??

[Harold Ritter]

You don't necessarily need the P routers (non edge LSR routers). It's just that if you have any routers between your PEs (edge LSR routers), from a conceptual viewpoint they are considered as being P routers (label switches).