Facebook builds world's longest optical network

You know that the telecoms sector has undergone a serious paradigm shift when you get a press release announcing that “the world's longest [8-terabit] terrestrial optical network route” has been deployed in Europe – by Facebook.

Five years ago, posting that on April 1 might have lead some readers to assume this is a prank story. Today, it’s a legit press release (dated March 31, you’ll notice) from Infinera, which supplied equipment for the network, including its SDN-ready DTN-X platform.

According to Infinera, The new route is 3,998 km (with no regeneration) – stretching from Facebook’s data center in Lulea, Sweden to major hubs throughout Europe – and sports up to 8 Tbps of data transmission capacity. The network delivers 100G coherent transmission via 500G super-channels, featuring a forward-scale design to support 1.2-Tbps super-channels in the future.

Facebook isn’t the first major content provider to build its own long-haul fiber network – Google has been investing in optical networks for some time now. But it emphasizes the fact that content providers are emerging as a significant driver of the optical networking space as they seek a DIY approach to data center connectivity. From the Infinera release:

"Content providers, such as Facebook, are adding long-haul capacity at a rapid pace," said TeleGeography Research Director Alan Mauldin. "According to our research, private network capacity in Europe has increased more than 8-fold between 2010 and 2014."

A recent article from Computerworld sheds some light on Facebook’s hunger for next-gen optical. For a start, 10GE is a minimum requirement for east-west connectivity inside its data centers, while upstream connectivity is mostly 40GE with a few 100GE links. Facebook is also seriously interested in applying silicon photonics to things like rack-level computing.

Meanwhile, Facebook Director of Technical Operations Najam Ahmad explained during an Optical Society of America meeting on the sidelines of the OFC conference last month why Facebook would rather buy and build long-haul dark fiber capacity than lease it:

One reason is that leasing the kind of bandwidth Facebook needs is sometimes more expensive than just buying the fiber capacity. But by controlling the fiber itself, the company also can respond to rapid changes in traffic, he said.

"Leasing capacity takes too long. Usually four to six weeks," Ahmad said. "We want to be able to do it in four to six minutes."

Of course, one of the selling points of deploying SDN at the optical layer is that it gives optical network operators the ability to provision capacity as quickly as customers like Facebook want it. Pacnet is already doing just that, having extended its PEN service to the optical layer a few weeks ago. 

However, Pacnet is pretty far ahead of the pack in that regard. And while other longhaul operators will eventually catch up, clearly the Facebooks and Googles of the world can't wait that long.