Enhanced Convolution Approach for Connection Admission Control in ATM Networks

Abstract

In this paper the utilisation of the Probability of Congestion (PC) as a bandwidth allocation decision parameter is presented. We assume short buffers at the switch nodes to cope with cell level multiplexation contention (“bufferless” environments). Therefore, delay and cell delay variations are strongly bounded. Moreover, the Cell Loss Ratio (CLR) becomes the critical performance parameter. The validity of PC utilisation is compared with quality of service parameters in bufferless environments. The convolution algorithm is an accurate approach for Connection Admission Control (CAC) in ATM networks with small buffers. However, the convolution approach has a considerable computation cost, in terms of calculation and memory. To overcome these drawbacks, a new method of evaluation is proposed and analysed: the Enhanced Convolution Approach (ECA). In complex scenarios, with ECA, PC calculation can be carried out in real time while maintaining the desired accuracy. Several experiments have been carried out to compare the demanded bandwidth evaluated by: analytical methods, simulations and measurements in actual ATM switches. The main contribution of this paper is the proposal and analysis of ECA to the PC-evaluation for use in CAC schemes