Question

A team is deploying a multi-node GPU training cluster in a public cloud region that does not offer InfiniBand, but does offer instances with RDMA over Converged Ethernet (RoCE) support at 400 Gb/s per node. The training job is a large distributed model that relies heavily on frequent all-reduce collective operations across nodes. Which statement best describes the appropriate networking approach for this deployment?

Accepted Answer

Use RoCE-enabled instances so RDMA can bypass the CPU/OS network stack and provide low-latency, high-bandwidth collectives comparable in approach to InfiniBand

Answer

Abandon the cloud deployment because distributed training collectives are impossible without native InfiniBand hardware

Answer

Use standard TCP/IP sockets over the Ethernet links, since RDMA offers no measurable benefit for GPU-to-GPU communication

Answer

Rely solely on intra-node NVLink and disable inter-node communication to avoid the slower Ethernet fabric