Patent ID: 8023517

Claim:
A system comprising: a first router that is connected to: (1) a core router, and (2) an edge router that is connected to the first router and another device, the core router being a router that is connected only to other routers: a first module in the first router that: identifies a transit-only interface that connect only routers; sends an identification of the transit-only interface to a second module present in the first router; and a second module in the first router that: receives the identification of the transit-only interface from the first module present in the first router; maintains, using the identification of the transit-only interface, a list of transit-only interfaces; determines, from the list of the transit-only interfaces, which transit-only interfaces are local to the first router: selectively omits transit-only route information pertaining to the transit-only interfaces from a topology table in the first router and also from a route table in the first router if the transit-only interfaces are not local to the first router; and writes the transit-only route information pertaining to the transit-only interfaces to a transit-only table, where the transit-only route information includes Internet Protocol (IP) addresses associated with the transit-only interfaces.