A robust methodology for the design of virtual paths in ATM network systems

In this paper, a robust logical network layer built on the top of the physical layer of a general network is introduced. End-to-end separated virtual paths (VPs) are established beforehand, and a set of alternative paths can be used in order to meet the required Quality of Service (QoS) for each class. A bandwidth pool is proposed to react to a high blocking probability of new incoming calls. A service separation has been chosen. The high percentage of blocking which characterizes service separation is decreased in the proposed mechanism. The performance of service separation with the proposed bandwidth pool, which is used to enlarge direct virtual paths, affects positively the blocking rate. A three level routing strategy is proposed: choose the direct path first, indirect path if necessary, or enlarge direct path otherwise (if possible).