Beshley M. Increasing the quality of real-time priority traffic service in multiservice network nodes

The thesis is devoted to the modeling and investigation of multiservice networks and takes into account improved methods of information flows management in network nodes. Quality of service time parameters, methods of prognostication and distribution of network resources have been investigated. A modified algorithm of prioritized processing of queues based on the proposed methodic of services prioritization has been developed. A testbed for modeling multiservice network has been created and its adequacy has been proved. The analysis of tasks of ensuring quality of service has been conducted and its importance for the development of modern multiservice telecommunication networks has been shown. It has been proved that the important aspect for improving the main indexes of QoS is solving the problem of routers buffer resource management when applying existing algorithms of queues processing and their modifications. A model and algorithm for resource management in multiservice network nodes have been proposed. The method of priority assignment has been improved. The algorithm for statistical prognostication of the buffer size, evaluation of QoS parameters and performance of the routers classifier under the conditions of multiservice traffic arrival has been developed. The algorithm of imitation model of dynamic distribution and channel throughput reservation has been developed. The method of optimal access node selection based on fuzzy logic has been perfected. The prognostication of the delay value for packets of service with i-th priority and nodes number for ensuring QoS based on the imitation model has been conducted. Based on the obtained dependencies the volume of necessary network node resources for ensuring the established level of QoS time parameters has been determined. Based on the proposed methodic of dynamic prioritization and modified algorithm of queue planning when processing aggregated load, in particular real time multimedia flows, the decrease in delay of processing and transmitting of the information flows of a great granularity in 5 times compared to existing algorithms WFQ has been achieved. Moreover the proposed solutions allow significant decreasing and stabilization of jitter which is very important for the real time flows. In this thesis it is proposed to use the developed methods and models in telecommunication structures as the basis for ensuring quality of service when constructing flexible long-haul transport systems with possibility of organization of scalable networks including broadband wireless networks. The system becomes especially effective under the conditions of significant load on the network communication core, since even slight decrease in delay of real time flows significantly increases quality of service, and in some cases is a major determining factor for ensuring responsiveness of network system on crisis situations.