A method, router and system for multicast stream forwarding

The method comprises the following steps: when the router reaches the multicast route or the unicast path of the convergence point RP is switched from the first route to the second route, the method comprises the following steps: when the router arrives at the multicast route or the unicast path of the convergence point RP, Establishing a new multicast forwarding path for the neighboring upstream router corresponding to the second route and forwarding the multicast data stream through the original multicast forwarding path; when the router receives the multicast data stream from the newly created multicast forwarding path , The original multicast forwarding path is disconnected and the multicast data flow is forwarded through the new multicast forwarding path. By adopting the method of the invention, it is possible to avoid the interruption of the multicast data flow when the multicast forwarding path is switched when the unicast switch arrives at the multicast source or the convergence point RP.