White Box Systems

Broadcom Ups Its Game in Ethernet Switching

Broadcom has begun sampling a new merchant chip for high-end Ethernet switches, specifically targeting the most demanding hyperscale networks.

The Tomahawk 3, announced to the world today, is the merchant chip that would go into white box switches -- or into the systems of OEMs that use merchant silicon, such as Arista Networks Inc.

With Tomahawk, Broadcom Corp. (Nasdaq: BRCM) is specifically targeting throughput. The new version packs 128 100-Gbit/s ports, multiplying out to a theoretical bandwidth of 12.8 Tb/s. Startup Innovium is the only other company to have announced a chip this large.

The chip is also primed for the upcoming 200-Gbit/s and 400-Gbit/s Ethernet standards and is capable of handling 400-Gbit/s flows internally, says Rochen Sankar, Broadcom senior director of marketing.

For years, Broadcom has enjoyed more than 90% market share in merchant silicon for Ethernet switches; The Linley Group put Broadcom's market share at 94.5% in 2015. The company now has a few startups to contend with, some of which are trying to leapfrog the chip giant. Barefoot Networks , for example, announced a chip with 65 100-Gbit/s ports at a time when Broadcom's highest-end chip had 32 such ports (Broadcom quickly caught up, though).

Innovium, founded at the end of 2015, is still working toward getting its first chip shipping in volume. And Cavium Inc. (Nasdaq: CAVM) got into this market by funding, then acquiring, startup Xpliant. (See Innovium Raises $38.3M and Cavium Claims Ethernet Switch Breakthrough.)

Broadcom is also facing some renewed competition from established competitor Mellanox Technologies Ltd. (Nasdaq: MLNX), which recently announced its latest switch chip. (See Mellanox Chip Shop Aims to Batter Broadcom With Next-Gen Ethernet Switch.)

One twist is that the Tomahawk series isn't meant to be programmable, whereas Barefoot, Innovium and Cavium all are all touting programmability as a central feature of their chips.

Broadcom contends that the hyperscale players are more interested in raw bandwidth and low power consumption. They're willing to sacrifice programmability for those metrics, Sankar says.

"We've done the microarchitecture to know how these tradeoffs play out," Sankar says.

Broadcom did add programmability to Trident, its chip line that targets more mainstream Ethernet switches. (That 90% market share was built largely on the Trident franchise.)

Going beyond straight bandwidth, Broadcom says hyperscale players want to adapt their networks to trends such as deep learning and storage disaggregation. Both are driving the need for lots of connections in the network, but operators don't want this to lead to lots of hops between switches; they'd prefer for each switch to fan out to as many devices as possible. That's where sheer port count -- having 128 100-Gbit/s ports rather than the 64 on the Tomahawk 2 -- becomes important, Sankar says.

It's also worth pointing out that Tomahawk 3 isn't only about bandwidth. The chip comes with some features, too. For example, it can detect so-called elephant flows in real time; these are the traffic flows that are enormous and pervasive, such as the kind created by streaming video. The chip is able to queue up these flows so that they don't block smaller flows from getting through.

— Craig Matsumoto, Editor-in-Chief, Light Reading

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