This article includes a list of general references, but it lacks sufficient corresponding inline citations. (September 2010) |
Link-state routing protocols are one of the two main classes of routing protocols used in packet switching networks for computer communications, the others being distance-vector routing protocols.[1] Examples of link-state routing protocols include Open Shortest Path First (OSPF) and Intermediate System to Intermediate System (IS-IS).[2]
The link-state protocol is performed by every switching node in the network (i.e., nodes which are prepared to forward packets; in the Internet, these are called routers).[3] The basic concept of link-state routing is that every node constructs a map of the connectivity to the network in the form of a graph, showing which nodes are connected to which other nodes.[4] Each node then independently calculates the next best logical path from it to every possible destination in the network.[5] Each collection of best paths will then form each node's routing table.[6]
This contrasts with distance-vector routing protocols, which work by having each node share its routing table with its neighbors, in a link-state protocol, the only information passed between nodes is connectivity related.[7] Link-state algorithms are sometimes characterized informally as each router "telling the world about its neighbors."[8]