Improved Routing Strategies In Complex Networks Based On Local Information

With the rapid development of society, communication networks such as the Internet havebecome indispensable necessities of daily life, which plays an important role in today’s society.However, network size and the number of users have grown explosively, and congestion hasbecome an inevitable phenomenon of network. Serious congestion will make network throughputand transmission reducing, and may even cause the collapse of the entire network. Therefore, howto mitigation and control network congestion and how to improve the communication capability ofthe network by routing strategy have become an important research direction of traffic dynamics.Early studies of complex network’s congestion control were carried out on a homogeneous network,but most of the communication networks possess the characteristics of the power-law distribution,so the study on the scale-free network routing strategy has important practical significance. Thisdissertation is based on the research of previous work on network congestion and optimal routingstrategy, deeply studies the routing strategy based on the local information, and propose twoimproved routing schemes to enhance network throughput and transmission performance.The main contents and contributions of this dissertation are as follows:(1) Aiming at the deficiencies of the traditional routing strategy based on local information, onan improved routing method based on local information is proposed on scale-free network. Thisalgorithm is only related to the degree of a node, and the improved method can choose the adjacentnode which has the smaller degree with a greater probability. And by this way the hub node can beavoided, the transport burden of the hub node can be reduced and the handling capacity of thenetwork can be maximized. Some simulations and relate theoretical proof are given to demonstratethe effectiveness of the proposed method, showing that this strategy does better than traditionalrouting strategy based on local information.(2) For the case the global information of a large network can not be available, on scale-freenetwork model, we present an improved routing method. When selecting the next hop node, weconsider not only the static topology structure such as the degree of the node of the network, butalso the current traffic flow condition of the node, for example, the length of the buffer queue andthe packet processing capacity of the node. In order to be close to the actual communication model,we assume that the node with larger degree has larger information packet processing capability,making it proportional to the degree of the node. For the nodes with smaller degree, we make its packet processing capacity be a constant. Simulations results show that there exists an optimalcontrollable parameter to make the throughput of the network achieve the maximum.