RoutingPrinciples

Routing is the process of determining a message path from source to target (which are not directly connected) using multiple other hosts in the middle. Low level network communication is usually point to point and does know routing. Therefor higher level protocols need to be established -- routing protocols.

Many objectives lead to different routing mechanisms serving different ranges of application. This article will discuss the routing principles, the basic protocols, which are basis for many other optimized and specific protocols.

While Distance Vector and Link State Routing serve to show these principles, Destination-Sequenced Distance-Vector Routing is an example for a more specific, Ad-Hoc Network oriented implementation.

Distance Vector Routing (DV)

History

Distance Vector -- also known as Bellman-Ford or Ford-Fulkerson -- is a dynamic routing algorithm, meaning it dynamically determins the route for each packet independently. DV is the original ARPANET routing algorithm, was replaced by Link State Routing in 1979, though.

Routing Table

In DV each router maintains a routing table containing one entry for each router in the subnet.