Where We Stand with SDN

One gauge of industry progress on the software-defined networking front is the momentum of the Open Networking Foundation (ONF), the user-lead group that is spelling out the core SDN standards and championing the cause.

By John Dix
Mon, December 02, 2013

Network World — One gauge of industry progress on the software-defined networking front is the momentum of the Open Networking Foundation (ONF), the user-lead group that is spelling out the core SDN standards and championing the cause.

According to Marc Cohn, chairman of the ONF Market Education Committee and senior director for market development at Ciena, the ONF now has close to 110 members, vendors have released more than 60 products that support the ONF's OpenFlow protocol, and some 30 million Open- Flow-enabled ports have shipped.

Progress indeed.

But don't confuse that with activity in production shops. "One of our clients said, 'If SDN was a baseball game, we haven't finished singing the National Anthem yet,'" says Joe Skorupa, vice president and distinguished analyst at Gartner. "A lot of folks are trying to come to terms with what they need to do and how to get there."

Not that these folks are laggards.

[ALSO: Planning for SDN]

After all, the standards are still evolving and the strategic direction of the leading network vendors is still coming into focus. Regarding the former, the ONF just ratified version 1.4 of the OpenFlow protocol in August, even as the ONF board called on the industry to focus their efforts on version 1.3 in an effort to get everyone on the same page and provide industry stability.

OpenFlow is the standard way

SDN controllers communicate with and control OpenFlow-compliant network devices in these newly bifurcated environments. Bifurcated in that, with SDN, the network control plane is separated from the data plane, meaning control of the network is pried out of the devices that forward the packets and centralized on a server, what the ONF calls a controller. See: Understanding SDN

Rather than the classic approach of each network device forwarding traffic based on knowledge about adjacent devices, centralizing intelligence makes it possible to see the network end to end so decisions are based on a bigger picture and can take more variables into account, such as the needs of a certain application at a given time of day.

And when it comes time to make network changes, you do it at the controller and the configuration changes and policy updates are pushed out to the individual components instead of requiring you to update each link in the chain.A

This is the broad view of SDN, where all resources, physical and virtual, play together in a softwarecontrolled world. While it may take some time to reach that nirvana given the huge installed base of legacy gear, the lower hanging fruit is network virtualization, which involves overlaying a software controlled network in a hypervisor environment to stitch together virtual server assets. This is the approach being driven by VMware using technology picked up in its 2012 acquisition of Nicira.

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