How RDMA Works — Animated Data Path

Remote Direct Memory Access: application → Queue Pair → Memory Region → RNIC → fabric → remote memory, with kernel & CPU bypass. Pick an operation and step through it.
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Payload data Work Queue Entry (WQE) Doorbell (MMIO) DMA transfer Network packet ACK Completion (CQE)
Key idea: once memory is registered, the RNIC moves data straight between registered buffers by DMA. The kernel is off the data path (kernel bypass), and for one-sided WRITE/READ the remote CPU is never interrupted (CPU bypass, zero-copy). ←/→ step · Space play/pause.