There is emerging interest in the use of MPLS LSPs for the delivery of multicast traffic. Efficient delivery of multicast traffic using MPLS requires P2MP LSPs. This document describes a mechanism to setup P2MP LSPs using PIM-SSM and LDP. PIM-SSM is a widely deployed multicast routing protocol and has well defined procedures for signalling multicast traffic. LDP is a well defined mechanism for distribution of MPLS labels. Utilizing both PIM-SSM and LDP for setting up P2MP LSPs keeps the clear separation between signalling and label distribution, and minimizes changes to both protocols. PIM-SSM signals when to receive multicast traffic and LDP distributes label information regarding how to receive multicast traffic.