A method of operating a communication network comprises receiving loopback addresses from a plurality of edge networks at a provider router of a core backbone network, the edge networks and the core backbone network being logically distinct from each other, advertising the loopback addresses to a transport route reflector element, propagating the advertisement of the loopback addresses to other provider routers of the core backbone network using a protocol for communicating between autonomous systems, and using the transport route reflector element to advertise at least one of the loopback addresses to a service route reflector element in one of the plurality of edge networks.