RDMACMEVENTESTABLISHED

RDMACMEVENTESTABLISHED is the name used for the RDMA Connection Manager (RDMA CM) event type that signals a successful establishment of a connection between two RDMA endpoints. It is part of the RDMA CM API (such as librdmacm) and represents the point at which the CM layer has completed its handshake and a communication path has been established between the client and server.

In typical usage, applications create an event channel and monitor it for RDMA_CM events. When a connection attempt succeeds, the event loop receives an RDMA_CM_EVENT_ESTABLISHED event. The application usually acknowledges the event with rdma_ack_cm_event and then proceeds to configure or finalize the lower-level resources required for data transfer, such as QP state transitions and memory registrations.

The established event indicates that the connection at the CM level is ready, but it does not automatically imply that data transfer can begin. After this event, applications typically exchange necessary connection information (for example, queue pair attributes) and move the relevant QPs to the RTS state before performing RDMA operations.

Common related events in the RDMA CM lifecycle include RDMA_CM_EVENT_ADDR_RESOLVED, RDMA_CM_EVENT_ROUTE_RESOLVED, RDMA_CM_EVENT_CONNECT_REQUEST, RDMA_CM_EVENT_DISCONNECTED, RDMA_CM_EVENT_REJECTED, and RDMA_CM_EVENT_ABORTED. If a connection attempt fails, events such as REJECTED or DISCONNECTED may be observed instead of ESTABLISHED.

In code references, the constant is RDMA_CM_EVENT_ESTABLISHED. Some documentation or examples may refer to it in a compact form as RDMACMEVENTESTABLISHED.