Bandwidth Dynamic Allocation And QoS Control For Broadband Networks

In general, the bandwidth is at least 155Mbps in broadband networks, where bandwidth allocation is aimed at the control for Quality of Service(QoS), including network congestion control, Call Admission Control, QoS routing algorithm , virtual path's bandwidth allocation, and so on. The technologic advantages of ATM and IP are merged together by MPLS or InterServ. Using the RSVP and DiffServ technology in IP plus ATM framework, it is possible to provide QoS guarantee for multimedia session.This dissertation has conducted researches on these technologies around bandwidth allocation and QoS control. The main contributions of this dissertation include:·Proposing a new adaptive control algorithm for optimally distributing traffics based on collision function of distance metric.As the channel is used on statistical multiplexing mode in ATM networks, the session's traffics are generated burstly, it will lead the multiplexed flow poor in stability, so the aggregated traffic will fluctuate drastically. The more serious the congestion status are, the more the cells are discarded because of the block and overrun, it is difficult to guarantee the QoS. The existed traffic control technologies are algorithms based on each session only, so the global congestion control is needed to solve this problem, we provide a new method based on collision function sensitive to congestion, and use the collision function as the distance measurement of transmission channel. With this method, the network can response to congestion in local regions quickly and the routes in congesting status can be avoided, so as the adaptive control of optimal traffic distributing can be achieved, and thecongestion can be prevented in advance. Once congestion is appearing at some part in networks, it can be eliminated gradually by this algorithm.· Presenting a new QoS routing algorithm based AntNet. Weprovide a new QoS routing algorithm that is based on AntNet but different from the existed AntNet algorithms. The changes of link state can be detected in time by this algorithm, it can support global QoS routing perfectly. The emit of artificial ant within this method is driven by calling with the higher bandwidth requirement, the number of artificial ant is reduced largely, and the processing load is cut down when the request arrival rate is relatively high· Proposing a new method for bandwidth allocation of virtual paths using neural networks and masked genetic algorithms based on the model of multirate's traffic. The concept of virtual paths has become the key technology in the broadband networks. A control scheme using neural networks and masked genetic algorithms is proposed and applied to bandwidth allocation of the virtual paths in the broadband networks. The proposed scheme is capable of estimating utilization of the virtual path's network, and adaptively selecting optimal bandwidths of the virtual paths using masked genetic algorithms according to the arrival characteristics of the multirate's traffic and network environment. As the optimization problem is constrained, the traditional genetic algorithms are no longer applicable to this problem. The dissertation proposes the masked genetic algorithms to solve the optimization problem. Simulation results demonstrate the effectiveness of this kind of dynamic allocation.· Presenting a new admission control algorithm based on measurements and neural network estimation. Because of the diversity of traffic characteristics and the QoS requirement, it is very difficult to estimate QoS of statistical multiplexing traffic by preciseanalysis model. The method we proposed in this dissertation is based on arriving measurements of aggregated traffics using sliding window and estimation of the neural networks for cell loss rate, it can implement quick QoS estimation and call admission control using characteristic parameters inside the traffic. This method can fully take advantage of statistical multiplexing characteristics an...