Online Routing Problems for Broadband Networks

Abstract

The area of broadband communication networks gives rise to a large number of on-line problems. One of the most extensively studied problem in this area is the on-line processing of calls; two classes of problems have been considered: call control and load balancing. In the first case a sequence of requests for calls is given on-line to an algorithm which can be either accepted or rejected; the algorithm has to select a virtual circuit between the communicating parties of an accepted call, obeying the network constraints, with the goal of maximizing the total benfit of accepted calls. In load balancing the goal of the algorithm is to find virtual circuits for all calls that minimize the use of network resources. Algorithms for on-line problems are usually analysed in terms of their competitive ratio, i.e., the worst case, over all input sequences, of the ratio between the values of the solution found by an optimal off-line algorithm (that knows the whole sequence in advance) and by the online algorithm. In this talk we review the main results that have been proposed in the literature by presenting both deterministic and randomized algorithms for various kind of network topologies and discussing lower bounds.