US Patent 11362954 Tunneling inter-domain stateless internet protocol multicast packets

A router is configured for deployment in a first domain of a network. The router includes a processor and a transmitter. The processor is configured to access addresses of egress routers for a multicast flow that are partitioned into local addresses of egress routers in the first domain and external addresses of egress routers in a second domain of the network. The processor is also configured to prepend an explicit multicast route (EMR) to a packet in the multicast flow to form a first EMR packet. The EMR includes information representing the external addresses. The transmitter is configured to unicast the first EMR packet to an advertising border router (ABR) that conveys the multicast flow from the first domain to the second domain. In some cases, the router includes a receiver configured to receive another EMR packet from another router in another domain via a tunnel between the routers.