The designing of wide area networks is usually an optimization process with accurately selected optimization criterion. The most utilized criterions are the quality of service in the network (indicated by average packet delay), the capacity cost (channel capacity leasing cost) and server costs (cost of connecting servers or replicas at nodes). This paper studies the problem of designing wide area networks with taking into account those three criteria. Then, the goal is select servers replica allocation at nodes, network topology, channel capacities and flow routes in order to minimize the linear combination of average delay per packet, capacity cost and server cost. The problem is NP-complete. An exact algorithm, based on the branch and bound method is proposed. Some computational results are reported and several properties of the considered problem are formulated.