What is the Difference Between Link State and Distance Vector?

The main difference between link-state and distance-vector routing protocols lies in the way they gather and share information about the network topology. Here are the key differences between the two:

1. Information Gathering: Distance-vector protocols only need to know the state of their neighbors and the metrics for each path to a particular subnet. In contrast, link-state protocols require a complete picture of the network topology, as each router shares information about its directly connected links with all other routers in the network.
2. Data Sharing: Distance-vector protocols send their entire routing table to directly connected neighbors. On the other hand, link-state protocols flood the entire network with information about their directly connected links.
3. Algorithms: Distance-vector protocols make use of the Bellman-Ford Algorithm for making routing tables, while link-state protocols use Dijkstra's algorithm.
4. Bandwidth Requirements: Distance-vector routing requires less bandwidth due to local sharing, small packets, and no flooding. In contrast, link-state routing requires more bandwidth due to flooding and sending large link-state packets.
5. Router Utilization: Link-state protocols have higher router utilization as they need to keep information about the entire network. Distance-vector protocols have lower router utilization as they only need to know about their directly connected neighbors.
6. Network Convergence: Link-state protocols have faster convergence times as they have a complete picture of the network topology. Distance-vector protocols have slower convergence times as they rely on the exchange of information between neighbors.
7. Best Path Accuracy: Link-state protocols can deterministically compute the shortest path to any given destination using the Dijkstra algorithm. Distance-vector protocols base their decisions on the best path to a given destination based on local knowledge, which may not always result in the optimal path.

In conclusion, the choice between link-state and distance-vector routing protocols depends on the specific requirements of a network, such as network size, topology, and desired performance characteristics.

Comparative Table: Link State vs Distance Vector

Link State and Distance Vector are two different approaches to dynamic routing algorithms in computer networks. Here is a comparison table highlighting the key differences between them:

In summary, Link State Routing protocols have a broader perspective of the network, using a global view of the routers, while Distance Vector protocols work with the state of the neighbors' routers, using a more local view of the network.