Marvell's latest switch may not be fast but the timing is great

The chipmaker's Prestera DX1500 family brings Ethernet to OT networks

At a rather pedestrian 10Gbps, Marvell's latest networking silicon isn't going to win any races. But then again the chipmaker's Prestera DX1500-series switch chips and Alaska E1781 PHYs aren't destined for your typical enterprise or campus network.

The chips are intended for deployment in appliances on factory floors, power utilities, transportation, and other critical infrastructure where time, latency, and redundancy trump bandwidth any day.

In these environments, ensuring that packets arrive not just quickly but in the order intended can mean the difference between an assembly line working in harmony or falling into disarray, explains Reza Eltejaein, director of product marketing for Marvell's Ethernet switching business, in an interview with The Register.

This is one of the reasons Ethernet has been slow to enter the operation technology (OT) space until recently, he added. "There's some Ethernet shipping in that market but we believe that the growth is still yet to come."

However, unlike other OT switches, Marvell's DX1500 isn't using a proprietary protocol piped through an FPGA. Instead, the company has designed a switch for a new generation of deterministic Ethernet networks that take advantage of time sensitive network (TSN) standards. TSN isn't so much a standard in itself as a group of IEEE standards which govern network behavior around latency, packet loss, and timing.

The goal is to deliver deterministic networking over standard Ethernet at very low latencies – but it's not without caveats. For one, you can't just drop a DX1500-equipped switch into OT environment and expect it to work. While Marvell says its switch silicon can achieve the time and latency requirements of an OT environment, most legacy sensors and equipment weren't designed with Ethernet in mind.

However, as Industry 4.0 and industrial IoT initiatives take off, the company expects that to change. Even in brownfield environments, Eltejaein sees applications for this tech if only to make IT's life easier. By attaching the switch to control systems, the silicon can act as a bridge between IT and OT networks.

Marvell expects to sell the silicon to a variety of traditional OT and IT equipment vendors such as Schneider Electric, Cisco, or Extreme Networks. According to Eltejaein, the switch family is also quite flexible, supporting a wide range of configurations with as few as eight ports, or as many as 54 ports using the chipmaker's Alaska E1781 PHYs. The idea here is that if customers want to build appliances to bridge OT and IT networks, they're not stuck with more bandwidth or ports than they can use.

"What we're offering is a highly integrated solution," says Eltejaein. "We have integrated the CPU. In some systems we have integrated the PHY. We've integrated the switch. And we've integrated the TSN features."

"With that you get a smaller footprint, lower power consumption, simpler design and higher reliability because there are fewer components on the board," he adds.

Additionally, because the DX1500 shares the same APIs as other Prestera switches, like the 2K-4K announced earlier this year, the same control planes used to manage IT networks can also be applied to OT networks and vice versa. "Now, these two would have the same control pipeline, same API level, and now they're using one SDK," he says.

And because OT networks often operate in uncontrolled environments, Marvell has also instituted SecureBoot and MACsec security as standard, to prevent firmware tampering and encrypt device traffic.

Finally, as you'd expect from any industrial-focused appliance, the silicon is "ruggedized" in that it can operate in extreme temperature ranges from -40°C to more than 85°C.

Marvell's Prestera DX1500-series switch chips and Alaska E1781 PHYs are sampling to customers now. ®