On the IP network design problem with QoS constraints

Abstract

We present a model for the design problem of reliable IP networks with quality of service (QoS) constraints. The proposed model deals with: selecting the location of routers; selecting the router types (where a router type is characterized by its number of slots and its switch fabric capacity); selecting the interface card types (where an interface card type is characterized by its number of ports, by the rate and technology of each port and by the number of slots required to insert the card in the router); designing the access and the backbone network, and selecting the link types. The QoS constraints we refer to are bandwidth guarantees between the clients. Moreover, we not only consider the QoS that the planner wants to obtain for the normal state of the network, but also in the event of important failures (e.g., single router failure scenarios). The proposed model is adaptable to any type of routing and mechanisms used to reserve bandwidth. An illustrative network design example is presented and solved using a branch-and-bound algorithm. The results show that the model is very difficult to solve, even for small-size instances of the problem.