What is the difference between distance vector and link state routing protocols?

1. Routing Updates - First difference between link state and distance vector routing protocol is that Distance vector routing protocol send the entire routing table with an update whereas Link state doesn’t. Link State routing protocol sends only the incremental updates, means link state send the only update required in the network. It doesn’t send the entire routing table with an updates.

2. Send Periodic Updates - In distance vector routing protocol administrator has to set a timer in router for sending periodic updates either it is 30 sec or 90 as per the administrator and network convenience but it doesn’t happen with the link state routing protocols.  In link state  routing protocol updates are triggered, means it sends the updates only when if there is any change in the network happens like if there is any link down, link up, new router added in the network, new route found.

3. Broadcast and Multicast - Distance vector routing protocol sends the broadcast updates, means it send the update to all routers in the network (doesn’t happen with RIP 2) whereas in link state routing protocol updates are multicast. Link state routing protocol share the updates only with who requested for an update.

4. In distance vector routing protocol updates are sent to its neighbor router and it doesn’t have the visibility to the entire network. It only communicate with its neighbor routers whereas in link state routing protocol update send to entire network and it has the visibility to the entire network.

5. In distance vector routing protocol there is high availability for making loops in the network as it doesn’t have the information of the entire network. Its only communicate with its neighbor routers but in link state routing protocol there is very less chances for loops in network as it has entire network routes information.