As the link speed has grown steadily from 10 Gbps to 100 Gbps, high-speed data center networks (DCNs) require more efficient congestion management. Therefore, proactive transports, especially credit-based congestion control, nowadays have drawn much attention because of fast convergence, near-zero queueing and low latency. However, in real deployment scenarios, it is hard to guarantee one protocol to be deployed in every host at one time. Thus, when the credit-based protocols are deployed into DCNs incrementally, the network will convert to multi-protocol state and face the following fundamental challenges: (i) unfairness, (ii) non-convergence, and (iii) high buffer occupancy. In this paper, we propose a new protocol, called CCRP, aiming for converging credit-based and reactive protocols in data centers. Targeting the mostly deployed protocol, i.e. DCQCN based on explicit congestion notification (ECN), in DCNs, CCRP leverages the forward ECN to detect the network congestion in data queue and optimizes feedback control of the credit-based transports. Our experiment results show that this design can address the unfair link allocation and converge with reactive protocols rapidly. Furthermore, CCRP achieves high utilization and low buffer occupancy at the same time.

随着链路速度从10 Gbps稳定增长到100 Gbps，高速数据中心网络（DCN）需要更有效的拥塞管理。因此，由于快速收敛，接近零排队和低延迟，现今主动传输，尤其是基于信用的拥塞控制已引起了广泛的关注。但是，在实际部署方案中，很难保证在每个主机上一次部署一个协议。因此，当将基于信用的协议逐步部署到DCN中时，网络将转换为多协议状态，并面临以下基本挑战：（i）不公平，（ii）不收敛和（iii）高缓冲区占用率。在本文中，我们提出了一种称为CCRP的新协议，旨在融合数据中心中基于信用和反应性的协议。针对部署最多的协议，即 DCQCN基于显式拥塞通知（ECN），在DCN中，CCRP利用前向ECN来检测数据队列中的网络拥塞，并优化基于信用的传输的反馈控制。我们的实验结果表明，该设计可以解决不公平的链路分配问题，并迅速与反应式协议融合。此外，CCRP同时实现了高利用率和低缓冲区占用率。