Optimization methods for telecommunications networks physical and logical structures

B.A. Buhyl, O.A. Lavriv, M.I. Beshley, V.V. Chervenets

Lviv Polytechnic National University

The article deals with reasons why the planned network resource is not used completely. The main attention is paid to the dynamic routing protocol, which does not consider the current load of local network segments according to the principle of its functioning. In the paper local segments loading considers with existence of a constant flow to reduce the computational complexity of the proposed method. The method is proposed in the work to maximize the use of network resources and resource allocation improving based on alternative routes variation through less loaded local segment. The proposed method implemented as a simulation model in Matlab. It allows making decision on routes variation based on introduced efficiency index for resource allocation. The article shows results of two experiments on the proposed method to determine its adequacy. The task of the first experiment is to determine the effectiveness of the method to vary the network resources allocation for simple network structure. The second experiment compares the value of efficiency index for resource allocation with load balancing according to the protocol EIGRP and the one with route replacement. The proposed method replaces dynamically defined routes to alternative that maximizes the efficient use of shared network resource. The major factors influencing the effectiveness of a network resource handling is a network physical or logical structure. It depends on the number of edges in the network topology. Physical structure forms when designing the network in the future does not undergo significant modifications, so the paper proposes a method of physical structure selecting that will provide the highest flows service quality for a given number of nodes and edges. Physical structure redundancy increases with connectivity increasing, leading to a set of possible logical structures. Formation of these logical structures provides routing policies in the network. In this paper, we propose a comprehensive method of physical and logical structures selection, which provides the most effective use of network resources to ensure a high level of flows service quality. Routing protocols operation depends on the network physical structure, because it has to form the best logical structure. The criterions of logical structure effectiveness are the QoS parameters for transmitting flows. The main disadvantage of dynamic routing protocols is that the selection of the optimal route bases on mono-criterion metric does not considers all the network features and causes an ineffective use of network resources. At present, the only way to control the network resources allocation during the routing process is traffic balancing. It means that all equivalent routes are uses, through which you can reach the recipient.