Executive Summary:

Distance Vector and Link-State algorithms are two fundamental routing algorithms used in IP routing protocols. Distance Vector algorithms, such as RIP and IGRP, use distance and direction to determine the best route. In contrast, Link-State algorithms like OSPF and IS-IS maintain a complete map of the network topology and use the Dijkstra SPF algorithm to calculate the best path. This report will discuss the main differences between these two algorithms and the protocols that use them.

Introduction:

In IP networks, routers use routing algorithms to determine the best path to reach a destination. Distance Vector and Link-State algorithms are two main types of routing algorithms that differ in their approach to routing table calculation and the way they exchange routing information.

Distance Vector Routing Algorithm:

1. Principle: Distance Vector algorithms determine the best route based on the distance (number of hops) and a vector (direction) to reach a destination.
2. Routing Updates: Routers periodically exchange routing updates with their neighbors. Each router shares its routing table with its neighbors, which is then used to update their routing tables.
3. Routing Table Calculation: Distance Vector algorithms use the Bellman-Ford algorithm to update routing tables.
4. Example Protocols: Routing Information Protocol (RIP) and Interior Gateway Routing Protocol (IGRP) are examples of Distance Vector protocols.

Link-State Routing Algorithm:

1. Principle: Link-State algorithms maintain a complete map of the network topology and use the Dijkstra SPF algorithm to calculate the best path to each destination.
2. Routing Updates: Link-State protocols share information about their directly connected networks with all other routers within the same area. Routers exchange Link-State Advertisements (LSAs) to maintain an up-to-date view of the network topology.
3. Routing Table Calculation: Link-State algorithms use the Dijkstra SPF algorithm to calculate the shortest path to each destination.
4. Example Protocols: Open Shortest Path First (OSPF) and Intermediate System to Intermediate System (IS-IS) are examples of Link-State protocols.

Conclusion:

Distance Vector and Link-State routing algorithms are fundamental to IP routing protocols, each with its unique approach to routing table calculation and routing information exchange. Distance Vector algorithms, such as RIP and IGRP, are relatively simple but can suffer from slow convergence and routing loops. On the other hand, Link-State algorithms like OSPF and IS-IS provide a more sophisticated solution that scales better in larger networks and offers faster convergence. Understanding the differences between these algorithms is crucial for network administrators when choosing and configuring appropriate routing protocols for their network infrastructure.