SnapRoute, a startup that builds open source software that enables network engineers to customize commodity networking switches and routers to meet their exact requirements, announced a $25 million A round today, led by Norwest Venture partners.

Lightspeed, AT&T and Microsoft Ventures also participated in the round and Norwest’s Rama Sekhar will join the SnapRoute board of directors.

Company founder and CEO Jason Forrester came from Apple, and it was there that he learned that when your data centers reach hyper scale, the underlying networking hardware doesn’t always behave the way you think it will.

He also found that many times the traditional vendors were giving you a switch with every single configuration option under the sun, when maybe your problem only required a couple of options. Those additional options not only increased the cost, they increased the complexity.

That’s when he came up with the idea for FlexSwitch, an open source network operating system that gives network operators more control and flexibility than traditional networking hardware vendors like Juniper and Cisco. “The problem with the traditional network guys is that it’s one size fits all. [Our solution] is designed to give [our customers] the ability to customize for a particular use case with only the code you need,” company founder and CEO Jason Forrester explained.

By separating the hardware from the software, it enables network operators, especially ones charged with building data centers at scale, to buy the cheapest commodity hardware that meets their needs, and design it for their unique requirements, something that was only previously within reach for hyper scale companies like Facebook and Amazon.

Forrester says that today he’s seeing non-tech companies building their own switches too, and for him, that’s changing the market. “When these down market folks are comfortable enough to design their own switch, and they can execute on that, then network space is changing,” he said. SnapRoute wants to be the operating system for that hardware.

As for monetization, SnapRoute open sources the parts of the stack that give the network folks the flexibility they need, but it holds back some key features to make money. “The protocols themselves are open source. The standards are open source, but there is a closed source piece — the hardware abstraction layer to support network at scale. That piece is closed source. That’s what we charge a subscription for,” he said.

Today, SnapRoute has around 35 employees, but with the $25 million funding, that should increase as they begin to build the company. Although he couldn’t share any customer names just yet, he says that Fortune 50 companies are interested in this product. “We won some of the biggest logos out of the gate,” he said.