Abstract: Internet’s traditional shortest path first routing algorithm may lead to congestion in its nature.Network congestion will not only degrade the performance of the network,but also break ISP’s QoS guarantees.By combining traffic engineering objectives in routing procedure,we can reduce the risk of congestion and improve the utilization of network resource.In this paper,we try to give a survey on recent advances of constraint based routing algorithms for traffic engineering.We first present three main traffic engineering objectives：minimization of resource usage,load balance and minimum interference.And then we examine typical algorithms.This paper ends with a conclusion and some future research directions.

Key words: constraint based routing, traffic engineering, QoS, path selection

摘要： 互联网中传统的最短路径路由算法本质上存在导致拥塞的可能。网络拥塞不仅会降低网络性能,而且会使得服务提供商难以完成对客户的服务质量保证。通过在路由选择阶段面向流量工程实施优化,能够避免拥塞,提高网络资源利用率。概述面向流量工程的约束路由算法的研究进展。首先阐述了三类主要的流量工程优化目标：最小化网络资源占用、负载平衡和最小干涉,然后分析了各类典型算法,最后对此方向的研究进行了总结和展望。

关键词: 约束路由, 流量工程, QOS, 路径选择