Routing Strategies in Computer Networks

A principal function of distributed computer networks is message routing in which a data unit is moved along a network path from where it is first accepted (source node) to where it is to be delivered (destination node), through possibly one or more network nodes. In the OS1 protocol architecture, routing is the principal function of Level 3, the Network Layer. 1 In most operational networks, the network automatically generates the routes used to forward data units. To use network resources efficiently, selected routes must involve minimum cost, according to some specific cost criteria, such as the number and type of communications channels on the route, the utilization levels of the channels, and the average delay incurred in transporting a data unit along the route. The cost of a route is the sum of the costs of the constituent links. Once we know the cost of the network links, we can calculate the minimum-cost path for any source-destination pair using algorithms developed in operations research. Major issues related to routing include