Summary: | 碩士 === 國立臺灣大學 === 電機工程學研究所 === 91 === This thesis proposes a new TCP-friendly congestion control algorithm designated for multimedia transport over best effort network, namely Adaptive Multi-Rate Transport Protocol (AMRTP). Compared to current TCP-friendly congestion control algorithm, AMRTP does take data rate generated by upper layer protocol into consideration. As a consequence, the sending rate of AMRTP may be any combination of discrete sending rate, while other approach use continuous sending rate or require some restriction among those data rate generated by application. AMRTP uses virtual congestion window as its bandwidth estimation. The growth of virtual congestion window could be governed by any of existing TCP-friendly congestion algorithm. More over, by adaptively tuning the congestion control parameters, AMRTP is able to capture network transient dynamics while maintaining smoothness in steady state. To further reduce the sending rate variation, AMRTP calculate normalize the RTT at each congestion epoch to dispel large sending rate variation caused by queuing delay. Finally, the difference between estimate sending rate and application data rate is masked using probabilistic decision. From the simulation result, AMRTP is able to maintain high utilization, fairness and TCP-friendliness over wide rage of network settings.
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