In the present work, the problem of routing in packet-switching computer networks has been considered in order to minimize the mean delay of packets. Routing algorithms are applied at network nodes to perform the routing decision. This thesis presents the evaluation of two known routing algorithms. The first is the distributed minimum delay routing algorithm of Gallager. It is a heuristic algorithm with information exchange between nodes. The second is the centralized Flow Deviation (FD) routing algorithm. The FD Algorithm is a computational algorithm based on the shortest path notion. These two algorithms are used in the quasi static environment. Gallager and FD algorithms were applied to networks whose topologies are random, with a maximum of (7) nodes, (22) links, and (19) commodities. A large number of simulation results is given. The convergence of Gallager algorithm to the minimum average delay (less than 70 ms) will be experimentally demonstrated. Verification of convergence limits is done by the use of the FD algorithm . Results are also presented for the adaptivity of Gallager's algorithm. The development of several procedures makes this algorithm adaptive to sudden changes such as (I) link or node addition, (ii) possible link deterioration, (iii) step change in the input flow rate. The adaptivity will be experimentally confirmed by many simulated case studies. The scope of the FD algorithm is extended, so its adaptivity will be evaluated. Introduction new procedures makes this algorithm adaptive against (I) link or node addition, (ii) possible link deterioration.