Link-state routing protocol

A Link-state routing protocol is a protocol concept used in routing of packet-switched networks in computer communications, as in for example the OSPF for Internet traffic.

Workings

In contrast to the distance-vector routing protocol which works by sharing its knowledge of the entire network with its neighbors, link-state routing works by having the routers tell every router on the network about its closest neighbors. The entire routing table is not distributed from any router, only the part of the table containing its neighbors.

1. The neighbor information is gathered continuously.
2. The neighbor information list is then broadcasted to every router that can answer to this protocol, a process known as flooding, which means that it sends the information to all of its neighbors who in turn send it to all of their neighbors and so on. Soon, all routers on the network have this information.
3. The neighbor information is flooded whenever there is a (routing-significant) change in the network.
4. As every router knows everything about the network by structuring the information from other routers, it can calculate the best path to any host on any destination network by using Dijkstra's algorithm.