Bandwidth Management of Virtual Paths - Performance Versus Control Aspects -

Abstract

In the B-ISDN the asynchronous transfer mode is used, which is subdivided into the virtual path (VP) level and the virtual channel (VC) level. For an efficient network operation, economic resource management at both levels is required. In our paper we will focus on VP management. We will evaluate the performance of different bandwidth allocation strategies for VPs (e.g. loss probability for VC connections) and their influence on the processing load for the VP bandwidth manager, which is part of the VP management. These investigations show that an improvement in performance, relating to decreased loss probability and/or increased offered traffic, is possible by using virtual path bandwidth management based on a partial-sharing strategy with two limits. It is shown that these limits of an optimal strategy can easily be determined in a totally symmetric system (i.e. all VPs and VCs on a link are of the same kind and the same bandwidth demand, all VPs have the same offered traffic). The evaluations for an asymmetric system show that it is very difficult to determine the optimal strategy because there are too many variable, correlating parameters. This paper elaborates some rules to obtain a strategy for improved performance despite these difficulties.