Introducing Ethernet Scale Up Networking: Advancing Ethernet for Scale-Up AI Infrastructure
New Scale-Up Networking Collaboration Announced at OCP Global Summit
As AI systems continue to grow in scale and complexity, Ethernet is once again evolving to meet the challenge. At the OCP Global Summit 2025, Broadcom, together with AMD, ARM, Arista, Cisco, HPE Networking, Marvell, Meta, Microsoft, NVIDIA, OpenAI and Oracle announced a new collaborative effort called Ethernet for Scale-Up Networking (ESUN).
With the initiation of this workstream, the OCP Community now has the opportunity to work on areas that address scale-up connectivity across accelerated AI infrastructure. The scale-up domain in XPU-based systems can be viewed in two primary areas: 1) network functionality, and 2) XPU-endpoint functionality.
First, the network aspect of scale-up focuses on how traffic is sent out across the network switches themselves, including protocol headers, error handling, and lossless data transfer. This is what ESUN intends to address and what the planned OCP workstream by the same name will focus on. The workstream itself is planned to kick off shortly after the OCP Global Summit.
Second, in the XPU-endpoint domain, the design depends on factors such as workload partitioning, memory ordering, and load balancing, and it is often tightly co-designed with the XPU architecture itself.
What is ESUN?
ESUN is a new workstream collaboration designed as an open technical forum to advance Ethernet in the rapidly growing scale-up domain for AI systems. This initiative brings together operators and leading vendors to collaborate on leveraging and adapting Ethernet for the unique demands of scale-up networking.
Key Focus Areas:
- Technical Collaboration: ESUN serves as an open forum where operators, equipment and component manufacturers can jointly advance Ethernet solutions optimized for scale-up networking.
- Interoperability: The initiative emphasizes development and interoperability of XPU network interfaces and Ethernet switch ASICs for scale-up.
- Technical Focus: Initial focus will be on L2/L3 Ethernet framing and switching, enabling robust, lossless, and error-resilient single-hop and multi-hop topologies.
- Standards Alignment: ESUN will actively engage with organizations such as UEC (Ultra-Ethernet Consortium) and IEEE 802.3 (Ethernet) to align with open standards, incorporate best practices, and accelerate innovation.
- Ecosystem Enablement: By leveraging Ethernet’s mature hardware and software ecosystem, ESUN will encourage diverse implementations and drive rapid adoption across the industry.
Ethernet for Scale-Up Networking
What Are the Focus Areas for ESUN?
ESUN focuses solely on open, standards-based Ethernet switching and framing for scale-up networking—excluding host-side stacks, non-Ethernet protocols, application-layer solutions, and proprietary technologies.
How is this Different from SUE?
OCP has previously launched an effort to advance the endpoint functionality for scale-up networking through the SUE-Transport (Scale-Up Ethernet Transport) workstream (originally named SUE, it has been renamed and clarified as SUE-T in contrast to ESUN). SUE-T will carry forward some of the SUE work which was seeded with the Broadcom contribution of the version 1.0 specification.
Broadcom Commitment
Broadcom is looking forward to working with industry partners to advance an open and standards-based Ethernet architecture for scale-up AI systems. This effort reflects Broadcom’s ongoing commitment to support the OCP community and the broader ecosystem in defining interoperable, high-performance networking for AI workloads.
Broadcom’s recently-introduced Tomahawk 6 and Tomahawk Ultra switch families are aligned with this objective, providing the bandwidth, scalability, and congestion management capabilities required in scale-up AI deployments. In addition, Broadcom contributed the SUE (Scale-Up Ethernet) specification to OCP, which has evolved into the SUE-Transport (SUE-T) workstream. Together, SUE-T and ESUN define a unified, open framework that enables Ethernet to efficiently scale from endpoint to switch fabric, supporting the next generation of scale-up AI infrastructure.
Join the Conversation
At OCP, ESUN’s workstream will host regular, open meetings for all interested parties. Whether you’re representing an operator, vendor, or standards body, your participation is welcome as we shape the future of scale-up networking together.
Look for the official announcement in the OCP Global Summit opening, Broadcom and partner keynotes. Let’s build the next generation of open, scalable, and interoperable networking for AI and beyond.