Research Of TFRC Protocol In High Speed And Wireless Networks

With the rapid development of network technology and a large increament of multimedia real-time audio/video services, the traditional congestion control (TCP) suffers new challenges. The AIMD mechanism of TCP is not appropriate for multimedia transmission. When UDP protocols and TCP protocols sharing the network bandwidth, because UDP protocols have no congestion control mechanism and access the most of the bandwidth. Therefore, many scholars provide a new congestion control mechanisms TCP-Friendly congestion control protocols. In recent years, a variety of TCP-Friendly protocol been widely studied. TFRC (TCP-Friendly Rate Control) is the most important one.Firstly, the thesis reviews the researches of TCP-Friendly protocols in recent years, mainly focuses on the performance of TFRC protocols. Based on this study, there are some performance problems of TFRC in high speed and wireless networks. We will study these problems independently from the high speed and wireless networks.Second, we discuss the performance of slow start phase in TFRC. Based on the performance of TFRC in high bandwidth-delay product Networks, we divided the slow start strategy into three stages to improve network utilization and reduce packet loss rate. Simulation results show that the improved TFRC protocol－TFRC-Astart has improved the slow start performance,especially in high bandwidth-delay product networks.Then we study the performance of TFRC in wireless networks. Based on the poor performance of TFRC, we provide the improvement from two sides:the method of caluating RTT and distinguishment of the network status, which is based on Spike algorithm. Simulation results show that the improved TFRC protocol－TFRC-P has improved sending rate and reduced the delay jitter in wirless networks.Finally, the thesis summarizes the current existing open issues, and provides some further interesting directions on TFRC and TCP-Friendly congestion control protocols over new networks.