An Incast-Coflow-Aware Minimum-Rate-Guaranteed Congestion Control Protocol for Datacenter Applications

Abstract

Today s datacenters need to meet service level objectives (SLOs) for applications, which can be translated into deadlines for (co)flows running between job execution stages. As a result, meeting (co)flow deadlines with high probabilities is essential to attract and retain customers and hence, generate high revenue. To fill the lack of a transport protocol that can facilitate low (co)flow deadline miss rate, especially in the face of incast congestion, in this paper, we propose DCMRG, an incast-coflow-aware, ECN-based soft minimum-rate-guaranteed congestion control protocol for datacenter applications. DCMRG is composed of two major components, i.e., a congestion controller running on the send host and an incast congestion controller running on the receive host. DCMRG possesses three salient features. First, it is the first congestion control protocol that integrates congestion control with coflow-aware incast control while providing soft minimum flow rate guarantee. Second, DCMRG is readily deployable in datacenter networks. It only requires software upgrade in the hosts and minimum assistance (i.e., ECN) from in-network nodes. Third, DCMRG is backward compatible with and, by design, friendly to the widely deployed, standard-based transport protocols, such as DCTCP. The results from large-scale datacenter network simulation demonstrate that in the absence of incast congestion, DCMRG can reduce flow deadline miss rates by 3x and 1.6x compared to D2TCP and MRG, respectively. Moreover, DCMRG further reduces the coflow deadline miss rate by more than 40% and 60% and lowers the packet drop probability by 60% and 80%, in the face of incast congestion, compared to D2TCP with ICTCP and MRG with ICTCP, respectively.