Routing - Link-State vs Distance-Vector routing protocols

Dynamic routing protocols are used to exchange routing information between routing devices. Interior Gateway Protocols (IGPs) are separated into two primary groups based on their routing methodology: link state and distance vector.

Link state and distance vector routing protocols are two fundamental approaches used in network routing to determine the best path for data packets to travel across a network. Here's a comparison table highlighting their key differences:

FeatureLink State Routing ProtocolDistance Vector Routing Protocol
Basic ConceptEach router builds a map of the connectivity to the network, calculating the shortest path to every other node by using algorithms like Dijkstra's.Each router calculates distances to all nodes and forwards this information to its neighbors. Uses algorithms like Bellman-Ford.
Routing Information ExchangeRouters flood the entire network with information about directly connected links.Routers periodically share their routing tables only with their immediate neighbors.
Convergence TimeGenerally faster, as updates are propagated quickly and calculations are done concurrently.Slower, due to the iterative process of exchanging information with neighbors.
ScalabilityMore scalable due to hierarchical structuring. Can handle larger networks by dividing them into areas.Less scalable, as the routing tables can grow very large in expansive networks.
Bandwidth UsageHigher during the initial flooding of link state information, but more efficient once the network stabilizes.Lower initial bandwidth usage, but can become inefficient over time due to periodic updates.
Memory and CPU UsageHigher, because routers need to store the entire network topology and run complex algorithms.Lower, as routers only need to maintain information about adjacent routers and use simpler algorithms.
Example ProtocolsOpen Shortest Path First (OSPF) and Intermediate System to Intermediate System (IS-IS).Routing Information Protocol (RIP) and Border Gateway Protocol (EIGRP).
SuitabilityMore suitable for large, complex networks due to faster convergence and better scalability.More suited for smaller or simpler networks where routing simplicity and lower resource usage are prioritized.

These the main differences between link state and distance vector routing protocols, helping network engineers and administrators choose the appropriate protocol based on the specific requirements and scale of their networks.

For more details about how each type of routing protocol can be leveraged best, take a look at: