Abstract: A computing or controlling apparatus includes a remote direct memory access (RDMA) adapter device. Responsive to an initialized state, a create queue pair adapter device command is provided by a host processing unit. The adapter device processes the command to create a queue pair in the initialized state. Responsive to a ready to send (RTS) state, a queue pair state transition command is provided by the host processing unit. The adapter device processes the queue pair state transition command to transition the queue pair from the initialized state to the ready to send (RTS) state skipping over the ready to receive (RTR) state. However, if the adapter device processes a ready to receive (RTR) in-band RDMA WQE received from the host processing unit, the state of the queue pair transitions from the initialized state to the RTR state.

Abstract: Tunneling packets of one or more remote direct memory access (RDMA) unreliable queue pairs of a first adapter device through an RDMA reliable connection (RC) by using RDMA reliable queue context and RDMA unreliable queue context stored in the first adapter device. The RDMA reliable connection is initiated between a first RDMA RC queue pair of the first adapter device and a second RDMA RC queue pair of a second adapter device. The RDMA reliable queue context is for the first RDMA RC queue pair, and the RDMA unreliable queue context is for the one or more RDMA unreliable queue pairs of the first adapter device.