一种在接收端实现的TCP-Friendly拥塞控制机制

本文提出了一种基于速率的单播TCP-Friendly拥塞控制算法——RAAR(Rate Adaptation at Receivers)控制机制.RAAR是一种接收端的速率自适应算法,它抛弃了每包反馈机制,采用GAIMD(General Additive Increase Multiplicative Decrease)策略进行拥塞控制,其主要控制操作由接收方完成.本文建立了简化的数学模型对其进行吞吐量的分析,得到在RAAR中用于TCP-Friendly 的GAIMD拥塞控制中α与 β的关系.通过与TFRC及TEAR这两种重要的TCP-Friendly协议进行对比研究发现,RAAR协议在对TCP协议的友好性,协议内的公平性以及速率的平滑性等方面具有更好的综合性能.由于RAAR不需进行每包反馈,且主要功能在接收方实现,因此可方便地将该机制引入多媒体组播传输系统中.

A TCP-Friendly Congestion Control Mechanism Implemented by Receivers

A new unicast rate-based TCP-Friendly protocol called RAAR (Rate Adaptation at Receivers) is proposed.RAAR is a rate adaptive algorithm at receivers.It applies GAIMD (General Additive Increase Multiplicative Decrease) policy for congestion control and doesn't need to feed back per packet received.In RAAR,almost all complex operations of traffic control are carried out at receivers.A simple mathematical model is constructed to analyze the throughput of RAAR and get the relationship of α and β in RAAR for AIMD(Additive Increase Multiplicative Decrease)TCP-Friendly congestion control.Comparing with two important TCP-Friendly protocols,TFRC and TEAR,results are that RAAR has better performance in TCP-Friendliness,intra-protocol fairness and smoothness.RAAR is also a promising avenue of development for congestion control of multicast traffic,since it is not a per-packet acknowledgement and is mainly implemented at receivers.