Arista introduced the eXtra-dense Pluggable Optics (XPO) module, which delivers 12.8 Tbps of bandwidth over 64 electrical lanes and features an integrated liquid-cooled cold plate capable of handling more than 400 W of power. The networking company also announced that it has brought together around 45 leading optics module suppliers under a multi-source agreement (MSA) to develop and support XPO, though it named only three: Lightmatter, Eoptolink Technology, and TeraHop.

Figure 1. Arista Launches Liquid-Cooled Pluggable Optic Module for AI Data Centers.

According to Arista, XPO establishes a new category of pluggable optics, providing an alternative to ZR, ZR+, and 800ZR modules. It is particularly aimed at Octal Small Form-Factor Pluggable (OSFP) modules, which are widely used across optical networks in data centers—from hyperscalers to enterprises. Figure 1 shows Arista Launches Liquid-Cooled Pluggable Optic Module for AI Data Centers.

“More than 100 million OSFP modules are expected to ship this year, making OSFP the most significant optics module form factor in history,” wrote Arista co-founder and chief architect Andreas Bechtolsheim, along with Vijay Vusirikala, Cloud and AI Networking leader, in a blog about XPO. “OSFP will remain the highest-volume optics module form factor for the foreseeable future. However, the ever-growing bandwidth demands of large AI data centers are pushing OSFP beyond its design limits in terms of density, cooling capacity, and reliability.”

XPO delivers four times the front-panel density of OSFP, features integrated liquid cooling compatible with any type of optics, and significantly reduces failure rates. According to Arista co-founder and chief architect Andreas Bechtolsheim and Cloud and AI Networking leader Vijay Vusirikala, a single XPO module can replace the work of eight OSFP modules.

“In short, XPO enables customers to build large AI data centers using just a quarter of the switch racks,” they wrote. “This is critical for both scale-up and scale-out applications, where without XPO, the number of traditional switch racks would exceed the number of GPU racks.”

To illustrate, the authors considered a hypothetical 400 MW AI data center with 1,024 GPU racks, each housing 128 GPUs, for a total of 128,000 GPUs. Assuming 12.8 Tbps scale-up and 1.6 Tbps scale-out bandwidth per GPU, OSFP switch racks—at 1.6 Pbps per rack—would require more than 1,400 switch racks for the fabrics. With XPO, the number of racks drops by 75%, saving over 1,050 racks and 44% of floor space.

Arista also highlighted XPO’s water-cooling capability as a key advantage. “All large AI data centers will be liquid-cooled, and the switches powering them must also support liquid cooling,” Bechtolsheim and Vusirikala explained. “Although liquid-cooled cold plates can be added to flat-top OSFP modules, this does not substantially improve thermal performance.”

XPO modules are considerably simpler than OSFP modules, which contributes to higher reliability. “Each 32-channel paddle card has only one microcontroller and a single set of voltage converters—a 75% reduction in common components compared to four OSFP modules,” wrote Arista co-founder Andreas Bechtolsheim and Cloud and AI Networking leader Vijay Vusirikala.

Arista noted in a white paper that in large-scale AI fabrics with tens of thousands of optical links, component failures are statistically inevitable. “Yet the hard and soft failure rates of today’s optical modules remain higher than desirable for the operational reliability needed in such environments,” the company stated.

“A single module failure can disrupt or halt a multi-million-dollar training job, wasting compute cycles and causing significant financial loss. Diagnosing and replacing a failed module in a fabric with over 50,000 optical links presents a major operational challenge, often triggering cascading effects on job scheduling and severe resource fragmentation across the network,” Arista added.

Power consumption is another critical constraint in modern data center design. “High-density racks operate within a finite power budget, and every watt consumed by the network is a watt unavailable for revenue-generating compute resources,” Arista explained. “Optical interconnects must therefore deliver significantly lower power per transmitted bit. High efficiency is essential not only to reduce operational costs but also to maximize computational density and overall rack performance.”

XPO addresses this need in two ways. “First, it provides a clean electrical channel to the switch chip that supports a low-power linear interface. Second, it enables the use of the most power-efficient photonics technologies, as well as other low-power approaches such as RF-Microwave,” Bechtolsheim and Vusirikala wrote.

Source: NETWORK WORLD

Cite this article:

Priyadharshini S (2026), Arista Unveils Liquid-Cooled Pluggable Optic Module for AI Data Centers, AnaTechMaz, pp.186