Evaluation of Clustering Techniques to Estimate the Effective Bandwidth of a Markovian Fluid from Traffic Traces

Abstract

Integrated services digital networks, designed to transport data in real time, are modeled by a multiplexer system, where several data fluids share a single output. At the time of admission of a new connection, in order to maintain the quality of service (QoS), it is important to know the amount of available resources required by the connections sharing the channel. It is therefore important to have models for the sources and techniques that provide accurate estimates of the resources required for each of them. It is assumed that the network sources are modeled using the Generalized Markovian Fluid Model (GMFM) because of its versatility in describing traffic fluctuations. This is a Markovian fluid where the transfer rate is a random variable whose range and probability distribution are determined by the state of the modulating chain. To measure resource allocation, the concept of Effective Bandwidth (EB) is used, since it allows expressing this magnitude as a function of the model parameters, which will be estimated from traffic traces. As the size of the data to describe the behavior of a source is clearly enormous, they are studied using clustering techniques. In this work, different methods, supervised and unsupervised, are presented to estimate the parameters involved in the calculation of the EB. Finally, the performance of the estimators is analyzed by calculating partition comparison indices, corresponding to the dispatch intervals, which are based on the confusion matrix and the notion of mutual information entropy between partitions, on simulated data.