20 - Optimization Techniques in Connectionless (Wireless) Data Systems on ATM-Based ISDN Networks and their Applications

Abstract

Connectionless data service in an ATM-based B-ISDN can be realized directly by means of connectionless service function, which is provided in connectionless servers. This chapter discusses the way to locate a certain amount of connectionless servers among the switching nodes in a public ATM network for the internetworking of connectionless data networks. The problem is formulated as network optimization problems, which are similar to the p-median problem. Two optimization techniques, one based on the greedy method and the other using the branch-and-hound strategy, for determining the locations of connectionless servers are presented in this chapter. By finding the optimal locations of connectionless servers, an optimal virtual overlay network that has minimized total transport costs for connectionless data traffic can be constructed. Direct connectionless (CL) service is particularly suitable for delay-tolerant or non-real-time applications. As only the ATM layer is used to transport data, all data frames may arrive in sequence and with the lowest delay possible due to more specific routing at the ATM layer. It is remarkable that the best effort services do not reserve guaranteed non-preemptable bandwidth. Thus, the effective gain of statistical multiplexing is almost intractable. The effect of statistical multiplexing on VP-connecting connectionless servers (CLSs) is neglected while one is trying to find the optimal location of the CLSs in the formulation.