适用于实时应用的网络服务自适应系统

随着网络带宽可用性的提高以及网络延迟的减少,如何在端主机上保证网络传输的服务质量(End-hostQoS)已经逐渐成为一个关键的问题。尤其是针对分布式实时应用的环境:媒体流服务器,视频会议以及VoIP((Voiceover Internet Protocol)是一种以IP电话为主,并推出相应的增值业务的技术应用)。End-hostQoS的实现需要操作系统的支持,比如提供网络层的系统调度和流量控制。笔者在这篇文章中提出的QoS自适应系统可以在最优使用系统资源的基础上提供per-flow或者per-service-class的差别服务。并且通过将EDF调度算法同PID控制理论相结合,保证系统的实时响应、适应网络波动,在服务器瞬间过载的情况下,保证网络服务质量的平稳过渡。

End-host System for QoS-Adaptive Communication in Real-time Application

With the increase in available network bandwidth and reduction in network latency,more emphasis has been placed on the guarantee of the End-host QoS of network transportation,especially of guarantees for distributed video conferencing applications,and VoIP applications.End-host QoS requires support from the underlying Operation System(OS) in the form of network schedulers and traffic controllers.It proposes an End-host System for QoS-Adaptive Communication,which provides per-flow or per-service-class QoS guarantees and integrates PID control techniques into EDF scheduler algorithm so as to guarantee real time response,gracefully adapt to transient overload with maximizing the aggregate utility of the communication service across all clients.