Will light replace cables in blade servers?

Microsoft Research has its hands on a start-up's 32-way server that uses light and mirrors to get around the bottlenecks of traditional cabling.

Ina Fried Former Staff writer, CNET News
During her years at CNET News, Ina Fried changed beats several times, changed genders once, and covered both of the Pirates of Silicon Valley.
Ina Fried
3 min read

A start-up has plans to turn the traditional approach to blade servers on its ear, and it's not just smoke and mirrors. But it is light and mirrors.

For the past seven years, Lightfleet has been working on a technology that employs light signals to replace the cabling and switches typically used to connect various server nodes in a blade server. And as of December, it had delivered its first unit--to Microsoft's Research's labs.

Lightfleet's first product is code-named Beacon, a 32-node server that uses dual-core Intel processors along with standard off-the-shelf disks, memory, and storage all in a package that stands about 16 inches tall on a server rack (9U in server speak).

In Lightfleet's approach, light and mirrors replace the cabling traditionally used to connect the nodes in a blade server. Lightfleet

What's different is the way each node talks to the others, the so-called interconnections within the server. Although not typically the sexiest part of computing, the interconnections in a server blade play a critically important part in determining not just how fast it that server runs, but also how much power the whole data center uses and how much heat it throws off.

Just improving performance is a big deal. No matter how fast the chips and memory inside servers get, there is always the challenge of how fast one can connect the different nodes together. And, historically, the more nodes you put in a blade server, the more complex that job of interconnection gets.

But that's not the case with Lightfleet's approach. The company's motto--all to all, all at once--may sound like a bad reinterpretation of the Three Musketeers' slogan, but it's the key to how the company gets around the standard bottleneck.

Instead of having to pass the message from one server to the next or use a switch to route the various signals, each of Lightfleet's server nodes can broadcast the signal to all the others, and each node can receive the signal sent by every other node's transmitters.

Think of traditional signaling as trying to make a series of messenger deliveries throughout Manhattan. Whether you have a Ferrari or a Pinto, you are only going to move so fast through traffic. And even if you have a fleet of cars, things will only speed up so much. Plus you have the hassle of distributing all the packages.

Lightfleet's approach, meanwhile, is more akin to being able to deliver the messages by beaming them from rooftop to rooftop.

On the technical side, the receivers work a bit like a tiny video camera, capturing all of the light signals that come in so that something known as a demultiplexer can then translate the signals into a bunch of ones and zeroes.

Lightfleet is, of course, not the first to use optics for signal transmission. Fiber optics also take advantage of the fact that light moves faster than just about anything else. But with fiber optics, you've still got the signal only traveling from one point to another. With Lightfleet's approach, each node can talk to all 32 nodes at once.

(Intel, meanwhile, proposes a technology called Light Peak that be used to connect PCs to all manner of peripherals.)

Based based in the tiny Pacific Northwest town of Camas, Wash., Lightfleet is still in its infancy, even after seven years of work. The company, which got angel funding in 2006, has just 22 employees and expects to ship just a handful of systems this year.

"We want to really support our customers this year and make sure each of them gets the maximum benefit," said CEO John Peers. At the same time, he said, "You want to put out enough that we prove the claims we're making."

Still, the company hopes to follow in the footsteps of its far more famous customer and fellow resident of the Evergreen State.

"We hope to do to Camas what a certain company did to Redmond," Peers said.

Lightfleet ended up with Microsoft as its first customer a bit by accident. Some folks on Wall Street had heard about Lightfleet's technology and were interested in seeing it for themselves. Microsoft got wind of it and asked the company to stop by its New York offices while they were in town. Pretty soon, the colossus of Redmond was Lightfleet's first customer.

"We would have given our right arm to give it to these folks but they were good enough to buy it," Peers said.

A diagram showing Lightfleet's broadcast system in action. Lightfleet