基于DASH流媒体的TCP拥塞控制算法优化  

Optimization of TCP Congestion Control Algorithm in Dynamic Adaptive Streaming over HTTP

作　　者：吴桦 王凌 程光[1,2] Wu Hua;Wang Ling;Cheng Guang(School of Cyber Science and Engineering, Southeast University, Nanjing 211189;Key Laboratory of Computer Network and Information Integration (Southeast University), Ministry of Education, Nanjing 211189)

机构地区：[1]东南大学网络空间安全学院,南京211189 [2]计算机网络和信息集成教育部重点实验室(东南大学),南京211189

出　　处：《计算机研究与发展》2019年第9期1965-1976,共12页Journal of Computer Research and Development

基　　金：国家重点研发计划项目(2017YFB0801703);国家自然科学基金项目(61602114,61872080,61502098);赛尔网络下一代互联网技术创新项目(NGII20150108,NGII20170406);江苏省自然科学基金项目(BK20151416)~~

摘　　要：随着互联网视频流量的快速增长,流媒体传输技术也日新月异,从传统的使用UDP传输协议的实时流媒体协议到使用TCP传输协议的HTTP协议,各大视频服务提供商都在为获得更多用户不断发展新的流媒体传输技术.超文本传输协议上的动态自适应流媒体作为目前最流行的自适应流媒体传输技术,在提高用户观影体验方面具有很多的优点.但是它的分片传输所形成的ON-OFF传输模式会造成TCP流的突发.这种间歇性的流突发会对其他的应用产生一定的影响.当多个客户端同时竞争带宽时会造成播放器错误估计网络带宽,从而产生视频分辨率频繁切换,对用户体验产生极大的负面影响.TCP作为传输层的协议,其拥塞控制算法对视频的传输效率起着决定性作用,由于传统的拥塞控制算法不能很好地适应DASH流媒体的传输,提出了TCP-HAS拥塞控制算法.该算法基于TCP Vegas进行了优化,将带宽估计值与视频码率相结合用于设置TCP拥塞控制参数.实验表明TCP-HAS能够提升网络QoS,并能在多个用户共享链路带宽时提升用户观影体验.With the rapid growth of Internet video traffic, streaming media transmission technologies are also developed rapidly. From the traditional real-time transport protocol (RTP) over user datagram protocol (UDP) to hyper text transfer protocol (HTTP) over transmission control protocol (TCP), major video service providers are constantly developing new media transmission technologies to attract more users. As one of the most popular adaptive streaming media transmission technologies, dynamic adaptive streaming over HTTP (DASH) has many advantages in improving users experience. However, due to its fragmented transmission, the resulting ON-OFF transmission mode causes bursts of TCP traffic. The intermittent traffic bursts have an impact on other applications. When multiple users compete for the bandwidth at the same time, the players may estimate the network bandwidth incorrectly. This will cause the players switch among the different video resolutions frequently, and the users experience bad QoE (quality of experience). As the transport layer protocol, TCP congestion control algorithm plays a decisive role in the video transmission efficiency, but the traditional congestion control algorithm is not customized for the DASH streaming media transmission. This paper proposes a TCP congestion control algorithm TCP-HAS which adapts TCP Vegas to the DASH streaming media transmission. More specifically, bandwidth and video s bitrate are also used to set TCP congestion control parameters in TCP-HAS. Experimental results demonstrate that TCP-HAS can improve network QoS (quality of service) as well as QoE of the users when multiple users share the bottleneck link bandwidth.

关 键 词：自适应流 超文本传输协议上的动态自适应流 传输控制协议拥塞控制算法 体验质量 服务质量 

分 类 号：TP393[自动化与计算机技术—计算机应用技术]