Characterization and Admission Control of Delay Sensitive Traffic
Resource allocation is necessary for a network which guarantees quality of service. To avoid over allocating resources to increase network utilization, traffic sources must be characterized as accurate as possible. An important traffic characteristics is the burstiness of the traffic stream, which, unfortunately, does not have a unanimously acceptable definition. In this thesis, we provide a definition of burstiness based on the loss probability at a bufferless multiplexer. The definition is aimed at characterizing delay sensitive traffic streams which do not allow delay caused by buffering. This definition is utilized to characterize (or quantize) traffic streams for networks which vrovide only finitely many bit rates for users to describe their traffic. To guarantee quality of service,the quantized version has to be burstier than the real traffic. We present an optimum quantization algorithm which yields a quantized version that is burstier than the real source and achieves minimum loss rate for all possible allocated bandwidths. The quantized version, called a pseudo source, can be used to represent the real source and is considered by the network for bandwidth allocation. Using the optimum quantization algorithm,we design a real-time admission control scheme for ATM networds. Both global loss probability and individual loss probability are considered in the proposed admission control schemes. To cope with multiple quality of service requirements,the concept of burstiness is generalized to the case which the cells of each traffic stream are allowed to have different loss priorities. We prove the optimum quantization algorithm we proposed for single quality of service requirement environments is also applicable to this case. By using this property, we design an efficient admission control scheme for heterogemneous delay sensitive traffic with multiple quality of service requirements. Numerical results that our proposed admission control schemes are efficient.
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