XPO liquid-cooled pluggable optics MSA targets 12.8 Tbps modules for AI networks

Arista Networks has formed a multi-source agreement (MSA) for XPO, a 12.8 Tbps liquid-cooled pluggable optics module aimed at AI networking fabrics, including scale-up, scale-out, scale-across, and metro reach designs.

The XPO module is specified as a 64-channel pluggable delivering 12.8 Tbps per module. Arista says XPO enables a front-panel density of 204.8 Tbps per Open Compute Project (OCP) rack unit, which it describes as a 4x improvement compared to 1600G-OSFP optics. The module integrates a cold plate and is specified to cool up to 400 W per module.

On the interoperability side, the XPO spec is intended to support multiple optics standards, including DR, FR, LR, SR, and ZR/ZR+, plus “next-generation coherent-lite, slow&wide, copper, and RF-Microwave,” as Arista describes them. The MSA also covers different interface architecture options, with support for linear, half-retimed, or fully-retimed designs.

For data center operators building high-radix AI fabrics, front-panel density and thermal limits on pluggables are becoming first-order constraints, not footnotes. A 400 W cooling target per module and a stated 204.8 Tbps per rack-unit density point directly at the same practical problem: keeping optics serviceable at the faceplate while rack power density and liquid adoption keep climbing.

“The unprecedented growth in AI fabric bandwidth and the transition to liquid cooling requires a new generation of pluggable optics modules,” said Andreas Bechtolsheim, chief architect at Arista Networks. “XPO solves this challenge by providing fundamental improvements in density, cooling capability and reliability for pluggable optics modules.”

Microsoft’s Matthew Mattina, VP for AI systems architecture, said, “Microsoft believes this specification can help establish a robust, broadly adopted form factor that enables a diverse optical ecosystem.” Dell’Oro Group vice president Sameh Boujelbene said, “The success of any new optical form factor hinges on a strong ecosystem of suppliers,” and noted XPO support “by all major optical module suppliers.”

More information on the XPO MSA, including how to join, is available at xpomsa.com. Arista also published an executive blog post titled AI Datacenters are Reshaping the Optics Industry on its site.