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Ultra Accelerator Link (UALink) is an open specification for a die-to-die interconnect and serial bus between AI accelerators. It is co-developed by Alibaba, AMD, Apple, Astera Labs, AWS, Cisco, Google, Hewlett Packard Enterprise, Intel, Meta, Microsoft and Synopsys.[1] The UALink Consortium officially incorporated as an organization and electronics industry consortium in 2024, for promoting and advancing UALink.

Its first specification will provide interconnectivity specifically for a scalable network. The initial 1.0 version 200Gbps UALink specification, is based on the IEEE P802.3dj 200 Gb/s (Ultra Ethernet) PHY Layer. Each system node is made up of a host and as many accelerators as needed, and is managed by one OS image. The accelerators can be connected to the host using a variety of interconnect protocols (CXL, PCIe, XGMI, CHI c2c, Infinity Fabric). UALink Switches (ULS) connect up to 1024 accelerators within an AI ‘pod’, where each Accelerator is assigned a unique 10-bit routing identifier. Each UALink Switch port connects to a distinct Accelerator.[2] AMD Infinity Fabric is expected to be the main shared-memory protocol.[3]

The specification was due to be available to Contributor Members in 2024.[4] The 1.0 version (UALink_200) was released to the public in 2025. Members of the public can download an “evaluation copy” after providing contact information.[5]

Version 2.0 of the specification was published in April 2026.[6]

References

  1. ^ “UALink Members UCIe”. ualinkconsortium.org. Retrieved 2024-11-01.
  2. ^ “UALink 1.0 White Paper v3” (PDF). Archived from the original (PDF) on 2025-08-09.
  3. ^ Morgan, Timothy Prickett (30 May 2024). “Key Hyperscalers And Chip Makers Gang Up On Nvidia’s NVSwitch Interconnect”. The Next Platform. Retrieved 19 May 2026.
  4. ^ “ABOUT UALINK”. UALink Consortium. Retrieved 2025-01-20.
  5. ^ “Ultra Accelerator Link Consortium, Inc.™ UALink_200 Rev 1.0 Specification”. ualinkconsortium.org. pdf
  6. ^ Cooter, Maxwell (7 April 2026). “New v2 UALink specification aims to catch up to NVLink”. Network World. Retrieved 19 May 2026.

See also