Optimal Allocation of Rates in Guaranteed Service Networks

We examine the problem of rate allocation in Guaranteed Services networks by assigning a cost corresponding to a rate, and examining least cost allocations. We show that the common algorithm of allocating the same rate to a connection on all links along its path (called the Identical Rates algorithm henceforth) is, indeed, a least cost allocation in many situations of interest. This finding provides theoretical justification for a commonly adopted strategy, and is a contribution of this paper. However, it may happen that the single rate required is not available on some links of the route. The second contribution of this paper is an explicit expression for the optimal rate vector for the case where Identical Rates is in-feasible. This leads to an algorithm called General Rates that can admit a connection by allocating possibly different rates on the links along a route. Finally, we simulate the General Rates algorithm in a dynamic scenario, and observe that it can provide, at best, marginally improved blocking probabilities. Our conclusion is that the performance benefits provided by General Rates are not compelling enough, and the simpler Identical Rates suffices in practice.