Optimizing flooding of information in link-state routing protocol

Abstract

A technique modifies an asynchronous flooding algorithm associated with a link state routing protocol operating within an area of a computer network from a per-interface to a per-neighbor paradigm. A router executes the flooding algorithm to distribute its local state over its interfaces and throughout an area of the network to each neighboring router with whom it has an adjacency. The router maintains a list of neighbors within an area data structure. When a new neighbor (adjacency) arises on an interface belonging to the area, the router updates the neighbor data structure describing that adjacency by linking it to a corresponding entry in the list of neighbors. Utilizing information contained in the list of neighbors, as well as information describing the types of interfaces used by the neighbors in the list, the router marks each interface data structure within the area as either flooding-active or flooding-passive. Marking of the interface is performed in connection with an interface election process that selects a flooding-active interface on the basis of, e.g., interface cost, giving preference to faster interfaces. Thereafter, link state protocol data units (PDUs) are sent to the neighbors over those interfaces marked as flooding-active.