If we're bypassing TCP/IP, does that mean we need to build our own protocol on top of this to achieve the reliability guarantees etc provided by the TCP stack?
RDMA (remote direct memory access) is a zero-copy communication standard.
RDMA is a user-space networking solution, accessed via queue pairs: lock-free data structures shared between user code and the network controller (NIC), consisting of a send queue and a receive queue.
RDMA supports several modes of operation [such as] reliable two-sided RDMA operations, which behave similarly to TCP. With this mode, the sender and receiver bind their respective queue pairs together, creating a session fully implemented by the NIC endpoints.
Once a send and the matching receive are posted, the data is copied directly from the sender’s memory to the receiver’s designated location, reliably and at the full rate the hardware can support.
A completion queue reports outcomes. End-to-end software resending or acknowledgments are not needed: either the hardware delivers the correct data (in FIFO order) and reports success, or the connection breaks.
