Abstract: With the development of Software Defined Networking（SDN） data center, the problem about high latency of short flows is brought by competitions of long flows and short flows as well as TCP Incast. This paper proposes the SDN-D2TCP scheme to solve this problem. The scheme uses the advantages of SDN centralized control and detects many-to-one communication by controller, then predicts bottlenecks of switches caused by TCP Incast. Considering the requirements of latency-sensitive flows, the scheme combines the deadline-aware of D2TCP and the explicit congestion notification mechanism to modulate the congestion windows and improve the competitive power of short flows. The NS2 simulation experiments indicate that, compared with DCTCP and D2TCP, SDN-D2TCP can reduce the occurrence of TCP Incast effectively and ensure low latency for short flows.

Key words: software defined networking, data center network, deadline-aware, congestion control, TCP Incast

摘要： 当前SDN的数据中心发展迅速，针对数据中心网络存在的长短流竞争和TCP Incast引起的短流高延迟问题，提出SDN-D2TCP方案。该方案借助SDN的集中控制优势，利用控制器侦测多对一的网络流通信行为，预测交换机的TCP Incast发生瓶颈，并考虑时延敏感流的特性要求，结合D2TCP的时限感知和显式拥塞通知机制，调整拥塞窗口，增强短流竞争力。通过NS2实验仿真，相较于DCTCP与D2TCP，SDN-D2TCP能够有效降低TCP Incast的发生概率，保证短流低延时。

关键词: 软件定义网络, 数据中心网络, 时限感知, 拥塞控制, TCP Incast