The Nokia service model uses encapsulation tunnels through the core to interconnect 7450 ESS and 7750 SR service edge routers. An SDP is a logical way of referencing the entrance to an encapsulation tunnel.
The following encapsulation types are supported:
Layer 2 within Generic Routing Encapsulation (GRE)
Layer 2 within RSVP signaled, loose hop non-reserved MPLS LSP
Layer 2 within RSVP signaled, strict hop non-reserved MPLS LSP
Layer 2 within RSVP-TE signaled, bandwidth reserved MPLS LSP