What is the difference between link state and distance vector

In every router, they have an identical copy of the LSDB in memory. Distance vector routing protocols send periodic full routing updates, but sometimes, these full updates are limited by split-horizon, which is used as a loop prevention mechanism.

Split horizon does not let a route to be advertised to the same interface where the route is generated. When a router fails, it sends an immediately triggered message, which is called a triggered update. After a router learns about a failed route, it suspends split-horizon rules for that route and advertises a failed route and removes it from the network. When a route is down, every router is given a time called hold down timer to know about that failure, and it to be removed.

A distance-vector routing protocol requires that a router informs its neighbors of topology changes periodically while link state protocol require a router to inform all the nodes in a network of topology changes.

Products By Bayt. Use Our Mobile App. Get Fresh Updates On your job applications, and stay connected. Download Now. A router can verify all the known routes and alters its local routing table on the basis of the updated information received from neighbouring routing.

In link-state routing , each router attempt to construct its own internal map of the network topology. At the initial stage of start-up, when a router becomes active, it sends the messages into the network and collects the information from the routers to which it is directly connected.

It also provides information about whether the link to reach the router is active or not. This information is used by other routers to build a map of network topology. Then the router uses the map to choose the best path. The link state routing protocols respond swiftly to the network changes.

It sends triggered updates when a network change occurs and sends periodic updates at long time intervals such as 30 minutes. If the link alters state, the device detected the alteration generates and propagate an update message regarding that link to all routers.

Then each router takes a copy of the update message and update its routing table and forwards the message to all neighbouring router. This flooding of the update message is needed to ensure that all routers update their database before creating an update routing table that reflects the new technology.

OSPF protocol is the example link state routing.