互联网络服务质量路由算法研究综述

如何提供不同的服务质量(quality of service,简称QoS)是互联网络面临的一个重要问题,而服务质量路由(quality-of-service routing,简称QoSR)则是其中的核心技术和热点问题.QoSR的主要作用是为QoS业务请求寻找可行路径,这体现了QoSR的两个目标:(1) 满足业务QoS需求;(2) 最大限度地提高网络利用率.由于QoSR是NP完全问题,研究者们设计了很多启发式算法进行了广泛深入的研究.在有权图和QoS度量的基础上介绍了QoSR的基本概念,详细分析了面向单播应用的QoSR算法中的热点问题,并按照所求解的问题类型和求解方法,将这些算法分成以下几类:多项式非启发类、伪多项式非启发类、探测类、限定QoS度量类、路径子空间搜索类、QoS度量相关类、花费函数类和概率求解类.在分析每类中典型算法的基础上,总结和对比了各类的特点,进而详细剖析了算法的有效性,并基于此总结了基于概率模型求解QoSR问题的方法.最后指出了该领域中需要进一步研究的热点问题.

Research on Internetwork QoS Routing Algorithms:a Survey

It is a challenging problem to provide QoS (quality-of-service) guarantee for the next-generation networks, among which QoSR (QoS routing) is one of the key issues. QoSR seeks to find a feasible path for QoS traffic with two objectives: (1) providing the QoS guarantee for QoS traffic, (2) maximizing the utilization of the whole network. However, some multi-constrained QoSR problems, which are NP-complete, can t be resolved accurately in polynomial time. Thus heuristics are studied extensively in recent years. Based on the weighted graph netword model and QoS metrics, the basic concept of QoSR is introduced and the hot issues of the unicast QoSR heuristics are analyzed in this paper. QoSR algorithms can be classified into the several classes: polynomial non-heuristics, pseudo-polynomial non-heuristics, QoS metrics restriction, path subspace search, QoS metrics relation, cost functions study and possibility solution. After typical algorithms are analyzed, the summary and conparison are given for each of the above classes. The validity of algorithms is dissected in detail, including the routing loop problem, stale network state information, the impact of the network topologies and traffic models. Based on the validity analysis, a summary is given for the QOSR algorithms bases on probability models. At last, key issues are pointed out to be further studied in the QoSR field.