A township engineer asks why modern RoCE-capable IP fabrics bother with Explicit Congestion Notification. What role does ECN play?
Select an answer to reveal the explanation.
Short Explanation
ECN is the yellow traffic light for RDMA stacks—it waves “slow down” before you smash into a red drop. That early signal is why it shows up in modern RoCE fabric CoS designs.
Full Explanation
Explicit Congestion Notification allows network devices to mark packets when queues build, informing congestion-controlled transports (including RoCEv2-related stacks using ECN) to reduce rate before tail drops. It does not replace VXLAN, eliminate buffering, or authenticate BGP. Used with proper classification, ECN complements PFC-oriented designs for RDMA performance.