ZTE Corp. ZTE Corp. China Mobile China Mobile China Mobile China Telecom This document describes a Remote Direct Memory Access (RDMA) over Converged Ethernet version 2 (RoCEv2) congestion control mechanism, which is inspired by Really Explicit Congestion Notification (RECN) described in RFC 7514, also known as Fast Congestion Notification Packet (Fast CNP). By extending the RoCEv2 CNP, Fast CNP can be sent by the switch directly to the sender, advising the sender to reduce the transmission rate at which it sends the flow of RoCEv2 data traffic.