Ethernet switch sales for AI back-end networks more than doubled during the first quarter of 2026, according to a new report from Dell’Oro Group.

The analyst firm’s AI Back-end Networks Quarterly Report revealed Ethernet switches accounted for around two-thirds of data center switch sales in AI clusters in Q1, extending its already extensive lead as the leading network protocol.

While InfiniBand held 80% of the AI back-end market in 2023, Ethernet’s rise has been driven by engineering familiarity and the integration of lossless technology, which previously gave InfiniBand its advantage. Prior Dell’Oro Group research said Ethernet would dominate the data center-scale fabric space, projecting the protocol to drive around $80 billion in switch sales over the next five years.

This latest report shows Ethernet continues to command the backend, with AI cluster buildout driving strong demand for high-performance switches.

But while Ethernet dominates, InfiniBand demand looks to be rebounding, with the analyst firm stating related switch sales more than tripled during the quarter, owing to the ramp of switches being shipped as part of Nvidia’s Blackwell Ultra platform. Earlier this week, we got a glimpse at the first InfiniBand-centric co-packaged optic network switch, the Quantum-X Q3450-LD.

“While greenfield deployments may have contributed to some of this growth, we believe a significant portion of this demand was tied to upgrades of the installed base in brownfield deployments rather than greenfield expansion,” said Sameh Boujelbene, VP at Dell’Oro Group.

Despite InfiniBand’s resurgence, Ethernet accounted for the “vast majority” of 800 gigabit per second (Gb/s) switches sold during the quarter, as operators continue to upgrade their existing 400G stack, the report revealed.

Sample shipments of 1.6 terabits per second (T/bs) have also kicked off and are projected to ramp in the second half of 2026. Early examples include Broadcom’s Tomahawk Ultra, Edgecore’s AIS1600-64Os, and Aria Networks' switch line – with the latter pun running on Broadcom’s Tomahawk 6.

Beyond shipment specifics, the vendor landscape continues to vary.

Dell’Oro states Celestica regained its leading position during the quarter, though Nvidia remains hot on its heels with networking becoming a core component of its infra offering beyond solely GPUs.

Arista, meanwhile, ranked third, despite what the analyst firm noted as a significant portion of its AI-related product revenue being deferred.

“Including Arista’s deferred revenue for the quarter, its AI back-end network sales would have been very close to those of Celestica and Nvidia,” Boujelbene said. “Cisco recorded the largest share gain during the quarter and ranked fourth. We expect ongoing customer diversification, vendor competition, and the transition to higher speeds to continue driving share shifts in this market.”