Service Access Points (SAP) are linked to transport tunnels using Service Distribution Points (SDP). The service architecture of the 7210 platform allows services to be abstracted from the transport network.
MPLS transport tunnels are signaled using the Resource Reservation Protocol (RSVP-TE) or by the Label Distribution Protocol (LDP). The capability to automatically create an SDP only exists for LDP based transport tunnels. Using a manually provisioned SDP is available for both RSVP-TE and LDP transport tunnels. See the 7210 SAS-Mxp, R6, R12, S, Sx, T MPLS Guide for more information about MPLS, LDP, and RSVP.