DEME: Decouple packet marking from enqueuing for multiple services in data center networks

Abstract

Most of current Data Center Network (DCN) protocols leverage Explicit Congestion Notification (ECN) for congestion control. However, the majority of them assume single-queue scenario in each switch port, making their performance inferior in multiple-queue scenario. MQECN [1] solves this problem by periodically measuring the round time of queue scheduling, calculating a threshold for individual queue based on its weight and the measured round time, and adopting standard ECN in each queue. However, MQECN incurs non-negligible overhead for frequent round time measurement, and inaccurate round time measurement is unavoidable. To this end, we propose DEME, a light-weight DCN scheme for multiple-queue scenario with no need for round time measurement or per queue threshold setting. The core idea of DEME is to decouple packet marking from enqueuing, which means, when a packet is enqueued and the total queue length exceeds the standard threshold, instead of marking this newly arrived packet, we mark the head packet of the queue whose length exceeds its fair share the most. Experiments show that our light-weight DEME has similar performance with MQECN in terms of average Flow Completion Time and guarantees the fairness.