- Set NCCL_IB_DISABLE=0 to enable IB - Add IB-specific config (GID_INDEX, TC, TIMEOUT, RETRY_CNT, NET_GDR_LEVEL) - Update deprecated NCCL_BLOCKING_WAIT to TORCH_NCCL_BLOCKING_WAIT - Set NCCL environment variables before torch imports for proper initialization Co-Authored-By: Claude <noreply@anthropic.com>