Dynamic Priority-based Ordered Transmission for Mixed Flows in Data Center Networks

Increasing diversity of applications and services are being migrated to modern data center networks (DCNs), and these applications and services are typically generating various combinations of long and short flows with or without deadlines. However, most existing flow scheduling solutions for DCNs either adopt single-queue strategy (e.g., D²TCP) that inevitably results in non-urgent flows blocking urgent flows or multi-queue mechanism (e.g., Aemon) that is at the cost of packet reordering. In this paper, we present DPOT, a Dynamic Priority-based Ordered Transmission mechanism that is aimed at minimizing the flow completion time and deadline missing rate. To avoid the urgent flows being blocked by the non-urgent flows, the DPOT switch adopts different priority queues to buffer packets for different types of flows. What’s more, when the switch detects that a data flow promotes the priority of its packets, it utilizes a disorder-free flow scheduling mechanism based on dynamic prioritization to make sure that packets of the same flow arrive at the receiver without reordering. Through a series of experimental tests, we demonstrate that DPOT can decrease the deadline miss rate by up to 95% while reducing flow completion time by up to 45% in comparison to the state-of-the-art flow scheduling approaches.