Refined approximations for design and optimization of wide-area, multi-service broadband networks

The problems of route optimization, and the sizing of virtual paths and explicit routes in wide-area multi-service broadband networks are considered. The problems are formulated at the call-level in the framework of multi-rate, circuit-switched, loss networks, with effective bandwidth encapsulating cell and packet-level behavior. Various asymptotic results based on uniform asymptotic approximations (UAA) have previously been obtained to substantially reduce the complexity of the numerical calculations. This paper offers refinements (RUAA) to UAA to the loss probabilities and their sensitivities to the offered traffic for individual links. These results are used to obtain refined asymptotic approximations to the network´s loss probabilities and implied costs. While the numerical accuracy is considerably enhanced, the computational complexity remains effectively unchanged. The network design tool TALISMAN has been extended to implement the refined approximations. Numerical examples illustrate the accuracy of the RUAA