Facebook has been building its own servers and storage gear for years, and last June announced its first-ever networking gear in the form of a top-of-rack switch called “Wedge.” On Wednesday, the company furthered its networking story with a new switch platform called “6-pack,” which is essentially a bunch of Wedge switches crammed together inside a single box.
The purpose of 6-pack was to build a modular platform that can handle the increase in network traffic that Facebook’s recently deployed “Fabric” data center architecture enables. The Facebook blog post announcing 6-pack goes into many more details of the design, but here is the gist:
“It is a full mesh non-blocking two-stage switch that includes 12 independent switching elements. Each independent element can switch 1.28Tbps. We have two configurations: One configuration exposes 16x40GE ports to the front and 640G (16x40GE) to the back, and the other is used for aggregation and exposes all 1.28T to the back. Each element runs its own operating system on the local server and is completely independent, from the switching aspects to the low-level board control and cooling system. This means we can modify any part of the system with no system-level impact, software or hardware. We created a unique dual backplane solution that enabled us to create a non-blocking topology.”
In an interview about 6-pack, lead engineer Yuval Bachar described its place in the network fabric as the level above the top-of-rack Wedge switches. Facebook might have hundreds of 6-pack appliances within a given data center managing traffic coming from its untold thousands of server racks.
“We just add those Lego blocks, as many as we need, to build this,” he said.
Matt Corddry, Facebook’s director of engineering and hardware team lead, said all the focus on building networking gear is because Facebook user growth keeps growing as more of the world comes online, and the stuff they’re sharing is becoming so much richer, in the form of videos, high-resolution photos and the like.
That might be the broader goal, but Facebook also has a business-level goal that’s behind its decision to build its own gear in the first place, and to launch the open source Open Compute Project. Essentially, Facebook wants to push hardware vendors to deliver the types of technology it needs. If it can’t get them to build custom gear, it and dozens of other large-scale Open Compute partners can with immense buying power can at least push the Dells and HPs and Ciscos of the world in the right direction.
Corddry said there’s nothing to report yet about Wedge or 6-pack being used anywhere outside Facebook but, he noted, “Our plan is to release the full package of Wedge in the near future to Open Compute.”
If you’re interested in hearing more about Facebook’s data center fabric, check out our recent Structure Show podcast interview with Facebook’s director of network engineering, Najam Ahmad.