Computing approximate blocking probabilities for large loss networks with state-dependent routing

Abstruct — We consider a reduced load approximation (also referred to as an Erlang fixed point approximation) for estimat-ing point-to-point blocking probabilities in loss networks (e.g., circuit switched networks) with state-dependent routing. In this approximation scheme, the idle capacity dktribution for each link in the network is approximated, assuming that these distribu-tions art independent from link to link. This leads to a set of nonlinear fixed-point equations which can be solved by repeated substitutions. We examine the accuracy and the computational requirements of the approximation procedure for a particular routing scheme, namely least loaded routing. Numerical results for six-node and 36-node asymmetric networks are given. A novel reduced load approximation for multirate networks with state-dependent routing is also presented. 1. lNTRODuCTIO