Adaptation scheme based on network testing and performance analysis
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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((Additive Increase and Multiplicative Decreas).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 (Testing Increase and Testing Decrease): 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.Abstract: 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 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. TITD is adaptive to the network status, and is superior to AIMD (additive increase and multiplicative decrease) in TCP-friendliness and rate oscillation.
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Key words:
- congestion control /
- RTT /
- TCP-friendliness /
- rate oscillation
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