A receiver-driven transport protocol using differentiated algorithms for differential congestion in datacenters.

With the continuous development of applications, data centers run application traffic from various service providers, and the requirements for data center networks are also increasing. Congestion control has always been a hot topic of discussion. Prevalent sender-driven transport protocols require adjusting their sending rate after network congestion occurs, and the long feedback delay makes them susceptible to a buffer overflow. Therefore, receiver-driven transport protocols are proposed, and the receiver adopts credits to allocate downlink bandwidth to overcome network congestion. This type of scheme solves last-hop congestion and reduces congestion feedback latency. However, the existing receiver-driven transport protocol is insensitive to congestion location and thus reacts inaccurately to congestion. To address this problem, this paper proposes a congestion control algorithm with congestion location awareness. In this scheme, 1) we first design an ECN-based congestion detection method to achieve lightweight congestion types awareness, i.e., instantaneous congestion and continuous congestion. 2) Based on this, we further design a differentiated transmission control strategy. For instantaneous congestion, we adopt adaptive backoff and delay control algorithms. For continuous congestion, we employ a rate control algorithm to reduce in-network congestion. This does not require complex modifications to the switch. In our evaluation, the overall average flow completion time (FCT) of DCC is up to 21%, 89%, 1.5×, and 3.4× better than Homa, ExpressPass, Timely, and pHost, respectively.