Trends in Ethernet Switch Development


Here’s something you probably didn’t know. There is only a small number (maybe four) major suppliers of Ethernet switch fabrics in the world.

And: they’ve all been going in similar directions recently, following the same sort of trends as we’re seeing in general CPU silicon. The most notable of those trends are finer lithography and more integration, and both of these have made it easier to produce better products for the military. In particular, these changes have stretched things at both the bottom end (low speed) and the top end (higher speed) of the product range.

First, though, some background. The Ethernet switch relies on a piece of silicon referred to as a ‘switch fabric’. The fabric is connected to a set of Ethernet ports. The fabric is the device which decides where to forward each packet, so that it comes in on one port and gets forwarded out on another port (or several other ports.)

Within the military, switches are becoming more and more common, as an increasing number of devices (such as sensors) are now using Ethernet instead of specialist buses, like 1588. The military also has requirements that are not typical of the commercial Ethernet switch market, and some of the trends in Ethernet switch fabric technology have implications for use of the technology within the military.

Improved performance, less power

But to return to those trends… Finer lithography has meant improved performance and a reduced power draw for all levels of switch speed. The most obvious place for this is at the top end, where we’re now able to produce switches capable of large numbers of ports capable of 40 Gigabit per second (Gbps) traffic. The Abaco SWE540, for example, is a fully managed switch with 20 x 40Gbps ports (and 16 x 1Gbps ports) in a single 6U VPX card. This sort of switching capability was impossible to squeeze into a single card a few years ago. And: we’re now looking at putting this sort of capability in a 3U card before later this year.

More integration has brought a related, but different, advantage. Fabric suppliers are now using system on a chip (SoC) techniques to integrate CPUs into the switch fabric chipsets. This means that we can design a managed switch without using a separate CPU. This in turn means we use less board space (and less power) and so can fit more capability into a smaller space. Our favorite example of this is the RES3000 family of switches. These are very rugged switches within a really small enclosure, but still with all the management features required to provide a secure, robust and efficient network. This has been made possible because we have a highly integrated fabric and CPU chipset at the heart of it.

Of course, not all these trends play perfectly for the military. One of the areas where some compromise was made in integrating the CPU was with the processor clock speed – the CPUs that are integrated tend to be something like a little ARM, running at a few hundred Hertz. For most switch management roles, this is not important, as the software isn’t involved in most of the high-speed forwarding of packets. However, the clock speed tends to impact the start-up time. For the military, switch start-up time can be really important: imagine, for instance, if the switch is at the heart of all external vision for a combat vehicle. You are effectively ‘blind’ until the switch is up and running. Therefore, the difference between 30 seconds and two minutes is pretty vital.

Major advantages

For Abaco, our OpenWare switch management software (which is very focused on the needs of the military) has already given us some major advantages in this area. We had got the start-up time (which we define as “power-on to first packet switched”) down to about 15 seconds on some of our products. (See our white paper here.) Unfortunately, the move to SoC integrated CPUs has pushed that up again. However, with carefully focused OpenWare development, we again are under 30 seconds for most of our switch models. It is probably the case that switch manufacturers who are not able to tailor their software to military requirements could be pushed to start-up times measured in minutes!

So, these trends in silicon technology have had impact for our military customers. The 40Gbps market is now really active, especially for high-definition radar processing, and Ethernet switches can now support that. At the 1Gbps end of the market, smaller, less power-hungry devices can far more easily be deployed in vehicles and aircraft. It truly is a golden age for those who rely on Ethernet switches, as the military does – and even more so for those who rely on Abaco switches. While our competitors may have access to the same switch silicon we do, they don’t have access to OpenWare – and that’s the Abaco difference.

 


John Thomson's picture

John Thomson

John Thomson has been working on software for over thirty years, having done a degree in Computing Science in the early 80s at Glasgow University. His focus has always been networking, in particular Local Area Networks, including years working on international standards for protocols - back in the early days of the Open Systems Interconnection (OSI). Having worked for a number of multinational companies (both large and small) he has been with Abaco (or its predecessors) since 2000, and leads the team of software people working on OpenWare – our Ethernet switch management suite. The OpenWare team is based in Edinburgh and California.   He and his wife took a career break for five years in the early 1990s, and were heavily involved in relief and development work (with Unicef and others) in Ulaanbaatar, Mongolia. He still claims to remember enough of the Mongolian language to ask for some very interesting foodstuffs! 

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