Anycast service model and its QoS routing algorithm

来源期刊：中南大学学报(英文版)2001年第2期

论文作者：WANG Jian-xin CHEN Song-qiao CHEN Jian-er

文章页码：135 - 139

Key words：QoS; anycast service; network routing; randomized algorithm

Abstract: In the Internet, a group of replicated servers is commonly used in order to improve the scalability of network service. Anycast service is a new network service that can improve network load distribution and simplify certain applications. In this paper, the authors described a simple anycast service model in the Internet without significant affecting the routing and protocol processing infrastructure thatwas already in place, and proposed an anycast QoS routing algorithm for this model. The algorithm used randomized method to balance network load and improve its performance. Several newtechniques are proposed in the algorithm, first, theminimum hops for each node are used in the algorithm, which are used as metric for computing the probability of possible out-links. The metric is pre-computed for each node in the network, which can simplify the network complexity and provide the routing process with useful information. Second, randomness is used at the link level and depends dynamically on the routing configuration. This provides great flexibility for the routing process, prevents the routing process fromoverusing certain fixed routing paths, and adequately balances the delay of the routing path. the authors assess the quality ofQoS algorithm in terms of the acceptance ratio on anycastQoS requests, and the simulation results on a varietyof network topologies and on various parameters show that the algorithm has good performances and can balance network load effectively.