Ultra Accelerator Link

Overview

Ultra Accelerator Link (UALink) is an open industry specification for scale-up interconnects between AI accelerators within a rack or pod. It is positioned as a vendor-neutral alternative to proprietary scale-up fabrics (such as NVLink), enabling multi-vendor accelerator compositions in a single high-bandwidth, low-latency scale-up domain.

UALink defines the physical layer, link layer, and logical interface for accelerator-to-accelerator communication at bandwidths targeting hundreds of gigabytes per second per link. The standard is managed by the UALink Consortium, which includes AMD, Broadcom, Cisco, Google, HPE, Intel, Meta, and Microsoft.

At OCP Global Summit 2025, Google highlighted that OCP is developing complementary manageability and security solutions for UALink, ensuring that heterogeneous UALink-based AI clusters can be operated, monitored, and secured through open interfaces consistent with the rest of the OCP ecosystem.