Method for implementing multicast in rapid spanning tree protocol ring network

A method for implementing multicast in a Rapid Spanning Tree Protocol (RSTP) ring network comprising access equipment, the method comprising:

• configuring, at the access equipment, an uplink port and a port mode of the uplink port for each of multicast programs, wherein a variety of port modes including a fixed port mode, a root port binding mode and an upper layer querier port following mode are allowed to be configured to each of multicast programs separately;
• when the access equipment is aware that a RSTP root port is switched, transmitting by a RSTP protocol module at the access equipment a root port switching message including a changed RSTP root port to a multicast module at the access equipment, after determining by the multicast module that a first multicast program is binded to the RSTP root port in response to the root port switching message, updating by the multicast module a first uplink port of a first multicast program whose mode is configured to the root port binding mode to the changed RSTP root port, updating by the multicast module an ingress port of the first multicast program in a hardware multicast forwarding table and a transmitting port of a first uplink Internet Group Management Protocol (IGMP) packet of the first multicast program to the changed RSTP root port and transmitting a first IGMP REPORT packet from the changed RSTP root port to an upper layer querier device so as to ensure the access equipment is included in group members of the first multicast program;
• and
• when the access equipment is aware that an upper layer querier port is changed, updating a second uplink port of a second multicast program whose mode is configured as the upper layer querier port following mode to a changed upper layer querier port.