QoS ROUTING IN REAL TIME NETWORKS USING DISTRIBUTED ROUTE SELECTION APPROACH

Abstract

For a network to support real time services, it has to deliver performance guarantees. For this purpose, it has to make resource reservation and excise network control. Before reservation can be done, a path with the best chance to satisfy the resource requirement must be selected. This selection procedure is referred to as QoS routing. Existing distributed routing algorithms fall in two categories. One is preferred neighbor-based and the second is flooding-based. The preferred neighbor approach offers a better call acceptance rate, whereas the flooding approach is better in terms of call setup time and routing distance. There are three performance metrics, which are considered for relative evaluation of the routing algorithms: average call acceptance rate (ACAR) average call setup time (ACST), and average Routing distance (ARD). This thesis gives an overview of the QoS routing and discusses a new distributed route selection approach, called parallel probing, for real time channel establishment in a point-to-point network. This technique attempts to combine the benefits of both preferred neighbor and flooding approach, in a way to improve all the three performance metrics simultaneously, besides also improving resource utilization. In the presented work, the parallel probing approach is simulated and its performance is compared with that of flooding and shortest path first approaches. The relative performance comparison is done for three performance metrics (ACAR, ACST and ARD) for variations in different parameters. It has been shown that parallel probing approach is better than flooding and preferred neighbor based approach. The simulation model is developed in C++, and runs under Linux environment.