Kyryk M. Methods and models for content management in distributed infocommunication systems.

The dissertation is devoted to the problems of information transfer management in distributed infocommunication systems and in content delivery networks in order to efficiently use network resources of entire global information infrastructure and its national segment in particular. It is reached by increasing the productivity of information transmission in conditions of its volumes growth. Management of multiservice streams requires using system models and algorithms of traffic management to optimize the performance of networks. The dissertation presents the solution to the problem of developing the methodological provision of information transmission control in distributed infocommunication systems and content delivery networks in order to effectively use the network infrastructure, increase the systemic productivity and quality of service delivery due to dynamic load balancing. In order to increase the productivity and efficiency of the information transmission control in the content delivery networks during content volume growth, there have been developed the model of self-similar multiservice traffic in distributed networks of streaming user load transmission as well as the mathematical model of probabilistic-time characteristics of the multiservice network. These models take into account the structural and functional features of the access level architecture. The criteria of traffic types classification in modern multiservice networks and traffic identification methods are determined. It allows to obtain a dynamic traffic model, which assists to select adequately the algorithms of transmission control in the infocommunication networks. The approaches that are used to determine the degree of self-similarity for network traffic are presented. The mathematical modeling was carried out to determine the quality of service parameters, which confirmed that the use of arbitrary methodology for calculating service quality parameters is inadmissible for traffic with self-similarity characteristic. The methods for increasing the efficiency of using the radio frequency spectrum and for improving the service quality in the cognitive wireless access network with the possibility of equipment parameters’ adaptive adjustment are proposed. As a result time used for decision on the change of radio frequency channels was redused. The multimedia content transmission technology, concept and architecture of the content delivery network are considered. The mechanisms of load management in CDN networks are proposed to choose the optimal route and provide quality of service with the usage of the contributed target function. The main load balancing methods are considered, which allow to rationally distribute the load between servers of the network and improve the quality of service. The system service model in wireless networks is presented, which should be used for efficient allocation of resources in a wireless environment. The simulation model for servicing queues of the multiservice network with the use of data prioritization was developed. A comparative analysis of the operation of queuing algorithms in wired and wireless networks for different types of streams was conducted. An algorithm for assessing the quality of service in the multiservice telecommunication network, which takes into account the work of several mechanisms of queuing and overload management was developed. The synthesis methodology of content delivery networks based on the segment of global network infrastructure was proposed. It takes into account resource management methods, cross-sectional evaluation of their parameters, quality of service and the state of active network equipment, as well as dynamic load balancing, which made it possible to increase the system productivity and quality of infocommunication services by more efficient use of network resources.