数据中心对应用服务提出了越来越严格以及多样化的要求,例如,为使用户请求得到更多的反馈应答,大多数应用对传输延迟有最后期限的限制,使得更少的最后期限错过率成为各种协议争相比较的指标,因此出现了基于TCP的最后期限可感知协议.但这类协议存在优先级同步问题,即相似优先级流竞争时总是相继错过最后期限.为此,提出了基于优先级控制的两种降速协议HPD(highest priority deceleration deadline-aware data center TCP)和P²D(priority probability deceleration deadline-aware data center TCP),对具有侵略性的高优先级数据流进行自适应的降速处理.实验结果表明,与已有的D²TCP相比,降速协议在优先级高度同步的情况下能够减少20%的错过率.

In modern data centers, due to the deadline-agnostic congestion control in transmission control protocol (TCP), many deadline-sensitive flows cannot finish sending before their deadline. Therefore, providing high deadline meeting ratio becomes a critical challenge in typical OLDI (online data intensive) applications of DCN. Under the partition-aggregate workflow pattern, since all the responses of single request have the same flow deadline and size, they are likely to respond nearly at the same time, which may result in that all flows with similar priority miss their deadlines. In this paper, two kinds of deadline-aware TCP, HPD and P²D are proposed. By using the novel deceleration, HPD and P²D alleviate the impact of priority synchronization problem. At-scale NS2 simulations show that P²D reduces the fraction of missed deadlines by 20% compared to D²TCP.

国家自然科学基金(61462007, 61363067);广西信息科学实验中心开放基金