Configuring sessions in programmable networks with capacity constraints

The provision of advanced computational services within networks is rapidly becoming both feasible and economical. As computational services become popular, it is important to have effective methods for configuring application sessions so that they use resources efficiently. In this paper, we discuss the problem of configuring application sessions that require intermediate processing. The problem was introduced in an earlier paper, where we showed how to optimally configure sessions in programmable networks by reducing the session configuration problem to the problem of finding a shortest path in a special graph constructed for the particular problem. This layered graph method is quite flexible and can handle a variety of specific session configuration problems. However, it does not explicitly model limits on link bandwidth or processing capacity. In this paper, we show that the optimal session configuration problem is NP-hard when capacity is constrained. Nevertheless, we have found efficient heuristics for which the network performance closely approximates the performance that can be achieved with optimal session configurations.