Method, system and access service router for implementing multicast service

A system for implementing multicast service, the system comprising a multicast source, an Access Service Router (ASR) to which the multicast source belongs, a General Switch Router (GSR) and an ASR in a service area, wherein:

• the multicast source is configured to:
• send a multicast service packet of which a destination address is configured to be a Group Access Identity (GAID) assigned to the multicast source;
• the ASR to which the multicast source belongs is configured to:
• search for a corresponding GRID in an established GAID-Group Router Identity (GRID) mapping table according to the GAID after receiving the multicast service packet, and send the multicast service packet to the GSR by adopting the found GRID;
• the GSR is configured to:
• search for a corresponding multicast tree according to the GRID of the multicast service packet, and send the multicast service packet to the ASR in the service area according to the multicast tree;
• the ASR in the service area is configured to:
• search for a corresponding GAID in the established GAID-GRID mapping table according to the GRID, and send the multicast service packet to a terminal under the ASR in the service area by adopting the found GAID;
• wherein the system for implementing multicast service is applied to the Location Identification Separation Network, the GAID is used to identify multicast stream between the terminal and the ASR, the GRID is used to identify the multicast stream in a core network.