Broadcom: The Supplier Arista Cannot ReplaceNarrow moat

Arista does not make its own switching silicon. Its systems are built on merchant chips, overwhelmingly Broadcom's Tomahawk and Trident families, and that decision is central to both the moat and its limits. Buying the silicon let Arista put its engineering into software rather than into a fabrication roadmap, which is why one operating system runs the whole line.

The cost is a dependency Arista cannot design around. Broadcom sells the same silicon to every other switch vendor, so the hardware Arista ships is available to its competitors on similar terms — the differentiation has to come from EOS and systems engineering, which is exactly what the moat pages argue and exactly why gross margin is the number that tests it.

It also means a single supplier sits upstream of Arista's entire product line, setting the roadmap, the timing and the price. When Broadcom prioritises a customer or a generation, Arista's schedule moves with it. Broadcom's own pages in this collection describe the relationship from the other side, where Arista appears as the model customer that never became a competitor.

Watch whether Arista ever announces internally designed silicon. It would signal that the merchant model's limits had been reached — and it would put Arista into a capital-intensive business it has spent twenty years deliberately avoiding¹.