Multicast routing method, interconnection device, mesh network system and configuration method thereof

A multicast routing method and an interconnection device for a mesh network system, a mesh network system and a configuration method thereof are provided. The method includes, at each internal interconnection device among multiple interconnection devices of each processing subsystem: in response to receiving a multicast access request to a destination memory, determining a shortest path from each internal interconnection device to the destination memory based on a topology structure of the mesh network system; where the internal interconnection device has no link connected to an external processing subsystem; in response to determining that the number of the shortest path is equal to one, routing the multicast access request to the destination memory along the shortest path; in response to determining that the number of the shortest path is greater than one, determining a next-hop interconnection device for the multicast access request based on a second static routing policy.