Ethernet for Scale-up Networking

Overview

Ethernet for Scale-up Networking (ESUN) is an OCP work stream launched at the 2025 Global Summit to standardize Ethernet for tightly-coupled AI accelerator scale-up networks. With 12 founding industry members — including major hyperscalers and leading XPU builders — ESUN establishes open Ethernet as the industry consensus path for AI scale-up networking beyond proprietary interconnects such as NVLink.

ESUN complements the Ultra Ethernet Consortium (UEC), which focuses on scale-out (longer-distance multi-rack AI training fabrics). Together, the two initiatives establish Ethernet as the open standard across all tiers of the AI fabric stack: UEC for scale-out, ESUN for scale-up.

Broadcom contributed its Scale-up Ethernet (SUE) specification to OCP as a foundational input to ESUN. The SUE specification defines a standard transport framework for integrating Ethernet into accelerators (GPU/XPU/TPU), covering push/pull memory access, ordering model, load balancing, and scheduling.