RDMA
Beginner
A way for a network card to copy data straight into another computer’s memory. Neither main processor has to help.
Novice
Remote direct memory access. Applications register memory with the NIC, and the NICs move data between those buffers directly, skipping the operating system’s networking code. That cuts latency and frees the CPU.
Expert
Kernel-bypass, zero-copy messaging with one-sided (read/write) and two-sided (send/receive) operations on queue pairs. The transport (ordering, acknowledgment, retransmission) runs on the NIC, which is why RDMA traditionally assumes a lossless fabric.
Explained in Scale-out networking (Systems).
See also: InfiniBand, RoCE (RDMA over Converged Ethernet).