基于区分服务的分层多播拥塞控制算法

多媒体多播应用在Internet上的广泛部署对拥塞控制提出了要求,分层多播是适应网络异构性较为有效的方案.为了克服现有分层多播存在的拥塞响应延时大、吞吐率抖动剧烈和不满足TCP友好的问题,给出了一个基于区分服务的分层多播模型,提出了一种基于区分服务的分层多播拥塞控制算法DSLMCC(DiffServ-based layered multicast packet dropping),在边缘路由器上引入了基于概率的区分优先级的分组标记算法,在核心路由器上采用区分优先级的分组丢弃算法.仿真结果表明,该算法能够有效地改进区分服务网络上的分层多播拥塞控制的性能,具有较快的拥塞响应速度、较好的稳定性和公平性,并且较好地适应了网络的异构性.

A Congestion Control Algorithm for Layered Multicast Based on Differentiated Services

Effective multicast congestion control mechanism is urgently needed with the deployment of multimedia multicast application in Internet. Layered multicast is considered to be an efficient approach to cope with the network heterogeneity. A Differentiated Services (DiffServ)-based layered multicast model is presented firstly. Then a congestion control algorithm for DiffServ-based layered multicast, called DSLMCC (DiffServ-based layered multicast packet dropping), including DSLMPM (DiffServ-based layered multicast packet marking) and DSLMPD (DiffServ-based layered multicast packet dropping) algorithm, is proposed through introducing probability-based priority packet marking and dropping mechanisms. Simulation results show that DSLMCC algorithm is more responsive, more stable and fair, and can adapt to network heterogeneity better.