Abstract: Routing in computer network is an essential functionality, which influence both the network management as the quality of services in global networks. The management of the traffic flows has to satisfy requirements for volume of traffic to be transmitted as avoidance of congestions for decreasing the transmission delays. These two requirements in general are contradictory. The optimal traffic management is a key issue for the quality of the information services. Routing in networks, applying shortest path algorithm is widely used in communication protocols in WAN. Short explanations and illustration of these algorithms is given.