OpenFlow: The Future of Google’s Network?

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The OpenFlow networking standard is feeling the embrace of the world’s largest network operators. And perhaps none more so than Google, which sees great potential for the open networking standard to solve sticky problems in its sophisticated data center infrastructure.

“We’re not using (OpenFlow) yet in production, but we’re spending a lot of time experimenting with it and we plan to implement it,” said Urs Hoelzle, Senior Vice President of Engineering at Google, who will also serve as the president and chairman of the newly-formed Open Networking Foundation. “Over the past two years we’ve been collaborating with other OpenFlow users on the spec, and bringing our real world expertise into its development. Our first application will be in the network that connects our data centers.”

By shifting management features from the switch to an external server, OpenFlow simplifies the task of creating a centralized management plan for a vast network of data centers like Google’s.

Improving Network Plumbing

“We would expect there will be quite a lot of innovation in the WAN,” said Nick McKeown of Stanford University, who helped develop OpenFlow. “There are fairly simple plumbing operations that are difficult to do now which will be simple with a global perspective.”

One example is prioritizing different types of traffic and developing policies for how the network handles congestion and equipment problems.

“We have a lot of types of traffic that flow between our data centers,” said Hoelzle. “OpenFlow can help us decide what suffers first and last, and how your arbitrage works. In an OpenFlow world, you can have a plan for how the network behaves. Right now we have to encode these behaviors into the network protocols. These networks were designed before the cloud existed, so they didn’t foresee this use case.”

Boost for Network Testing & Development

Hoelzle also was intrigued by the potential for tools like FlowVisor, a special purpose OpenFlow controller that acts as a transparent proxy between OpenFlow switches and multiple OpenFlow controllers. With FlowVisor, Hoelzle said, you can run multiple OpenFlow networks on the same physical hardware.

“That lets the network administrator test new versions on production hardware, but without affecting the live network,” he said. “It will make it much easier to adopt something new. You can test, to a high fidelity, how the changes will perform a new network.”

That’s important to Google, which updates its software and systems on an ongoing basis, a process Hoelzle once described as akin to “changing the tires on a car while you’re going at 60 down the freeway.” (see How Google Routes Around Outages for more).

Hoelzle emphasizes that it’s “very early” in the development of OpenFlow. As head of the Open Networking Foundation (ONF), he’ll have a front-row seat for the effort.

“The exciting thing about OpenFlow is that it opens up a playing area for network applications,” said Hoelzle. “My guess would be two years from now, you’ll see dozens of different areas that have open flow underneath somewhere.”

About the Author

Rich Miller is the founder and editor at large of Data Center Knowledge, and has been reporting on the data center sector since 2000. He has tracked the growing impact of high-density computing on the power and cooling of data centers, and the resulting push for improved energy efficiency in these facilities.

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