OCP Launches ESUN for Ethernet for Scale-Up

Jim Carroll

6 months ago

The Open Compute Project Foundation (OCP) has announced the formation of Ethernet for Scale-Up Networking (ESUN), a new community workstream to address the growing demands of AI-accelerated data center infrastructure. Introduced at the OCP Global Summit 2025, themed “Leading the Future of AI,” ESUN brings together leading operators and silicon vendors—including AMD, Arista, Arm, Broadcom, Cisco, HPE-Juniper, Marvell, Meta, Microsoft, and NVIDIA—to develop Ethernet-based solutions optimized for scale-up networking.

The initiative focuses on Ethernet’s role within tightly coupled, accelerator-based systems—sometimes referred to as the “scale-up domain.” ESUN aims to enhance how traffic is managed within network switches, including Layer 2/3 framing, lossless data transfer, error handling, and protocol optimization for single-hop and multi-hop topologies. This complements OCP’s existing SUE-Transport (SUE-T) effort, which targets XPU endpoint functionality such as workload partitioning, memory ordering, and flow control.

OCP describes ESUN as an open technical forum emphasizing interoperability between Ethernet switch ASICs and XPU network interfaces. The group will align its work with external standards bodies including the IEEE 802.3 and the Ultra Ethernet Consortium (UEC). By leveraging Ethernet’s mature ecosystem, the initiative seeks to accelerate adoption of open, standards-based scale-up networking and to ensure that Ethernet remains central to next-generation AI system design.

• ESUN focuses on Ethernet framing, switching, and lossless data transport for AI scale-up networks

• Complements OCP’s SUE-Transport initiative for endpoint functionality

• Initial members include AMD, Arista, Arm, Broadcom, Cisco, HPE-Juniper, Marvell, Meta, Microsoft, and NVIDIA

• Will coordinate with IEEE 802.3 and UEC to ensure alignment with open standards

• Excludes host-side stacks and proprietary or non-Ethernet protocols

“OCP’s mission is to accelerate innovation through openness and collaboration,” said an OCP spokesperson. “ESUN represents the next logical step in making Ethernet the foundation for scale-up AI infrastructure.”

🌐 Analysis: ESUN’s launch reflects a coordinated industry move to define Ethernet’s role in scale-up AI systems—a space increasingly dominated by proprietary interconnects. It also signals OCP’s deepening collaboration with the Ultra Ethernet Consortium, reinforcing Ethernet’s adaptability in an AI-centric data center era.