Distancevectorprotokollat

Distancevectorprotokollat is a class of routing protocols in computer networks that determine paths by exchanging distance vectors with neighboring routers. Each router keeps a routing table that lists reachable destinations and a metric indicating the cost to reach them, along with the next hop. Routers periodically send their distance vectors to directly connected neighbors, and upon receiving a neighbor’s vector, a router updates its own table using a Bellman-Ford calculation: the cost to a destination via that neighbor equals the neighbor’s reported cost to the destination plus the cost of the link to that neighbor. If a shorter path is found, the router updates its vector and propagates the change to others.

Key characteristics include the use of simple metrics (often hop count), distributed computation, and reliance on periodic or triggered updates rather than a global view of the network. Many distance-vector protocols support classful routing and employ techniques such as split horizon and poison reverse to reduce the likelihood of routing loops. Convergence—reaching a stable set of routes—tollows the propagation of updates but can be slow compared with link-state approaches and can suffer from problems like count-to-infinity and routing loops during changes.

Common examples and variants include the classic Routing Information Protocol (RIP) and its successors, as well as Enhanced Interior Gateway Routing Protocol (EIGRP), which extends the distance-vector approach with additional mechanisms to improve loop-free convergence. Distance-vector protocols are simple and lightweight, well suited for small networks, but face scalability and convergence challenges in larger or rapidly changing environments. As a result, many modern networks favor link-state protocols or path-vector strategies for large-scale deployments.