Patent ID: 7154889

Claim:
In a service-provider network comprising a plurality of interconnected provider edge routers and transit routers, a router method comprising the following steps: A) receiving from a source not in the service-provider network packets that include destination-address fields that specify final destinations that also are not located in the service-provider network; B) for each of a plurality of such received packets: i) making a routing decision based not only on the contents of that packet's destination-address field but also oil the source from which it receives that packet; ii) inserting into the packet an internal-routing field, determined at least in part in accordance with the source from which the edge router received the packet, that specifies a route to an interface on another of the provider edge routers; and iii) forwarding the resultant packet to another router in the service-provider network in accordance with the routing decision; and C) receiving from other routers in the service-provider network, packets that include internal-routing fields and destination-address fields and: i) forwarding some such packets without their internal-routing fields to routers, not located in he service-provider network, that it selects in accordance with a routing decision based on the contents of the packets' internal-routing fields; and ii) for other such packets, making routing decisions based on the contents of those packets' internal-routing fields without reference to those of their destination-address fields, and, in accordance with those routing decisions, forwards those packets to other routers in the service-provider network.