1. RoCE 1.1 Connectivity Requirements RDMA requires the same class of network end to end, for example the same /16 subnet. Single switch. RoCE: host NIC ── Ethernet switch (PFC) ── peer NIC Multiple switches. RoCE: host NIC ── Leaf ── Spine ── Leaf ── peer NIC When there are multiple hops, note:

1. What RDMA Is RDMA (Remote Direct Memory Access) is a technology created to solve the delay of server-side data processing in network transmission. With TCP/IP transmission, data passes through the network stack, then through the NIC to be sent; after the receiver receives it, the data is reassembled according to sequence numbers.

1. InfiniBand Network InfiniBand (abbreviated IB) is a computer network communication standard for high-performance computing. It offers extremely high throughput and very low latency, and is used for data interconnection between computers. InfiniBand is also used as a direct or switched interconnect between servers and storage systems, as well as between storage systems themselves.