US Patent 8018873 Enhanced link state protocol for identifying broadcast networks

An enhanced link state protocol is described for uniquely identifying broadcast networks having overlapping address spaces within a network system. A network device generates first and second link state advertisements (LSAs) in accordance with this link state protocol. The first LSA includes a first identifier dependent on layer 3 addressing information assigned to a physical interface of the first network device that interfaces with a layer 2 communication medium, e.g., an IP subnet address prefix. The second LSA includes a second identifier independent of the layer 3 addressing information assigned to the physical interface of the first network device that interfaces with the layer 2 communication medium, e.g., a unique network identifier associated with a broadcast network. By transmitting this second LSA to a second network device, the network device may uniquely identify broadcast networks having overlapping address spaces.