For all its faults, conventional cable is reliable. Engineers know exactly how much data the network can carry. That number won't change, regardless of rain, sleet, or snow.
Gigabit Wi-Fi offers no such guarantees. Championed by both Starry and Facebook's Terragraph project, the new technology uses higher frequencies to send data through the air at rates as high as 7 Gbit/s. But that speed comes with a price. The smaller waves are easily absorbed by moisture or flying objects, so any single link could degrade or drop out at any time. Since a given connection might rely on half a dozen different links, shepherding data through the system requires routing programs that can make smart decisions at almost instantaneous speeds. Outside of a few prototypes, the software to solve those problems simply doesn’t exist yet.
"Not something routing protocols in the past have been built to handle"
Today, Facebook announced a new software platform called Open/R to tackle that problem. The platform serves as a foundation for all the software running on Terragraph's various hardware units, and gives developers crucial flexibility in changing that software on the fly. Open/R can’t solve Terragraph’s complex routing problems by itself, but it offers a framework for testing out new routing programs faster and more effectively. Facebook hopes that Open/R's flexibility will give Terragraph a head start in figuring out how to move data through such an unpredictable network.
"Most routing protocols are about basic connectivity in a fixed wired network," says Omar Maldonado, who handles software engineering for Facebook’s networking team. "How do you handle varying rate conditions? Weather or other obstructions can change the amount of bandwidth you have very quickly. That’s not something routing protocols in the past have been built to handle."
That’s also a challenge facing Terragraph’s rival, Chet Kanojia’s Starry. Like Terragraph, Starry aims to deliver unprecedented connection speed through its gigabit Wi-Fi system, although many of the technical details are different. Still, the company has said little about the details of how it will manage the inherent instability of the higher-frequency signal.
Any solution to Starry and Terragraph’s problems could potentially be applied to the rest of the internet. While Open/R plays an integral role in Terragraph, it can be adapted to any kind of network, and Facebook plans to ultimately publish the platform as open-source. Open/R is already in place in Facebook’s internal server networks, as well as the Terragraph pilot system on the company’s Menlo Park campus. Terragraph is slated for a public test in San Jose later this year.