Patent ID: 7746859
Filing Date: 2010-06-29
Classification: H04L

Abstract:
1. A method for implementing multicast, comprising: copying and forwarding a multicast message sent by a multicast source to a user who joins a multicast group stage by stage according to a corresponding relationship between a private network multicast address and a public network multicast address established in a provider backbone bridging device (PBB), a private network multicast forwarding table, a public network multicast forwarding table and a Layer 2 multicast forwarding table of a backbone network established in a backbone network device (PB) in a backbone-virtual local area network (B-VLAN) multicast domain, wherein before copying and forwarding the multicast message, a user joins the multicast group by: A: sending, by a custom edge device (CE), an Internet Group Management Protocol (IGMP) report message for requesting to join a multicast group of a designated service instance to the CE in which the multicast source exists via the PBB and the PB; B: allocating, by the PBB, a public network multicast address, establishing the corresponding relationship between a private network multicast address and the public network multicast address, and generating a private network multicast forwarding table for identifying the multicast message out-port, according to the received IGMP report message; and C: transporting, by the PBB, private network multicast address information to the PB, and establishing the Layer 2 multicast forwarding table of the backbone network in the PB; transporting, by the PB, the IGMP report message to the CE providing multicast service in the designated service instance via the PBB in which the multicast source exists, and establishing the corresponding relationship between the public network multicast address and the private network multicast address and the public network multicast forwarding table in the PBB which the IGMP report message passes through.