Patent ID: 6526056
Filing Date: 2003-02-25
Classification: H04L

Abstract:
A communications system comprising:A) a set of customer nodes so divided into at least first and second customer-node subsets that no node of any given subset is a routing adjacency of a node of any other subset; and B) a service-provider network forming a virtual private network with the set of customer nodes and comprising a plurality of provider nodes including provider transit routers that form no routing adjacencies with any node of the set of customer nodes and further including at least first and second provider edge routers associated with the set of customer nodes, said first provider edge router being linked by a first provider-customer channel with at least one customer node, denominated a first customer edge router, in the first customer-node subset, said second provider edge router being linked by a second provider-customer channel with a plurality of customer nodes, denominated second customer edge routers, of which at least one is in the second customer-node subset, wherein: i) the first provider edge router includes circuitry for: a) receiving by way of the first provider-customer channel data packets that include destination-address fields that specify nodes in another of the customer-node subsets; and b) for each of a plurality of such received packets: (1) making a routing decision based on the contents of that packet's destination-address field; (2) inserting into the packet an internal-routing field that includes both an egress-router field and an egress-channel field and specifies a route to a channel that links another of the provider edge routers; and (3) forwarding the resultant packet to another router in the service-provider network in accordance with the routing decision; ii) the second provider edge router includes circuitry for receiving, from at least one other router in the service-provider network, packets that include internal-routing fields and forwarding them without their internal-routing fields by way of a second provider-customer channel that it selects in accordance withe the contents of the packets' egress-channel fields; and iii) at least one said provider transit router includes circuitry for: a) receiving, from other routers in the service-provider network, packets that include internal-routing fields and destination-address fields; b) making routing decisions based on the contents of those packets' internal-routing fields without reference to those of their egress-channel fields or their destination-address fields; and c) in accordance with those routing decisions, forwarding those packets to other routers in the service-provider network.