摘要
网络拥塞是基于包交换的IP网中不得不面对的问题 .流媒体应用有实时性等要求 ,需要检测网络拥塞状态并进行相应的调整 .传统的检测拥塞的方法是计算丢包率 ,而调整策略是AIMD ( (AdditiveIncreaseandMultiplicativeDecreas) .AIMD中的调整参数通常事先确定 ,不能很好地反映网络状态 .在对网络状态进行测试的基础上 ,提出了一种新的拥塞调整策略TITD (TestingIncreaseandTestingDe crease) :当网络拥塞时 ,发送速率直接降低到接收端实测的接收速率 ;当网络空闲时 ,速率增幅根据测试出的RTT值确定 .由于速率的调整自适应于网络状态 ,TITD策略在TCP友好性和速率波动方面均优于AIMD .
In packet-switched IP networks, congestion perhaps is unavoidable. Therefore, it is necessary to perform congestion control for real-time multimedia service. Usually, loss rate is considered as the sign of the network congestion and AIMD(additive increase and multiplicative decrease) is the adjustment scheme. It is difficult to obtain the optimal performance, because the parameters in AIMD scheme are fixed. An adaptation scheme TITD (testing increase and testing decrease) based on network status was proposed. When the network is in congestion, sending rate is reduced to the receiving rate obtained at the receiver. When the network is idle, the additive rate is according to the RTT (resonant tunnelling transistor). TITD is adaptive to the network status, and is superior to AIMD in TCP (transport control protocol)-friendliness and rate oscillation.
出处
《北京航空航天大学学报》
EI
CAS
CSCD
北大核心
2005年第1期5-7,共3页
Journal of Beijing University of Aeronautics and Astronautics
基金
国家 973资助项目 (G19990 3 2 7)
国家发改委"CJ IPV6合作项目"中间件子课题资助
关键词
拥塞控制
往返时间
TCP友好性
速率波动
Adaptive systems
Congestion control (communication)
Multimedia systems
Oscillations
Packet switching
Testing
