Ethernet is replacing the traditional storage networking technologies like Fiber Channel and Infiniband in Datacenters. The key feature of these traditional technologies that make them suitable for datacenter is their low-loss low-delay operation. Consequently IEEE 802.1 standards committee is developing new specification for congestion management for Ethernet in datacenter networks. Backward Congestion Notification (BCN) and Forward Explicit Congestion Notification (FECN) are two proposals. Each of the proposals has its own advantages and disadvantages. FECN outperforms BCN in fairness and response time while BCN is able to respond to sudden increases in load in less than a round trip time. In this paper, we propose an enhanced version of FECN that takes the best of both proposals and adds BCN if there is a sudden severe congestion. It is shown that E-FECN performs better than the previous proposals.
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