A Multicast Service Method in MPLS Network

PURPOSE: A multicast service method in an MPLS(Multi Protocol Label Switching) network is provided to eliminate the consumption of resources due to path establishment by making all groups share a previously established LSP(Label Switched Path), instead of forming a distribution tree for each group. CONSTITUTION: A BSR(BootStrap Router), the highest priority node among RP(Rendezvous Point) nodes, broadcasts an integrated, certified bootstrap message to the RP nodes periodically, and the RP nodes broadcast bootstrap messages to their respective LERs(Label Edge Routers)(101). Subscriber terminals transfer join messages to RP nodes through LERs respectively. The LERs and the RP nodes get to a group data forwarding state and a multicast forwarding state respectively by the transmitted join messages(102). If a packet is received from an arbitrary subscriber terminal to an adjacent LER(103), the LER analyzes the header of the received IP packet(104). Based on RP information delivered from the bootstrap message, the LER transfers the packet to an RP node appointed to service a group specified as the destination of the packet(105). The RP node reproduces the transferred multicast data packet as much as the number of LERs to which the members of the group are connected and delivers them to the LERs through an LSP(106). Each LER reproduces the delivered packet as much as the number of group members in an external network and delivers them to the subscriber terminals(107).