SDN: Open Source Advances Interoperability

I've been working actively in the area of software-defined networking for the past three years, with a particular focus on the challenges of delivering products that are both interesting and interoperable. I'm happy to report that recent events in the SDN space are bringing the once-cloudy future into much sharper focus.

Among other efforts, the Forwarding Abstractions working group I chair in the Open Network Foundation (ONF) will soon finalize a spec that will improve OpenFlow scalability and interoperability. The industry investments in network functions virtualization (NFV) and the progress at OpenDaylight are also very helpful.

If you've been tracking SDN, you know it refers to an architecture where the control plane can be decoupled from the data plane. But what does that translate to in practical terms? For example, should SDN-related topics already be part of your equipment purchase criteria? I expect you can guess the answer: "It depends."

Key dependencies include: How central is IT to your strategic differentiation? Do you have significant software development resources, or can you instead fund it externally? Does your industry suggest that you should be near the bleeding edge of IT?

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In the buzz around SDN, we've seen suggestions that convergence toward a new and common networking stack will soon occur. We're told it will resemble the familiar compute stack that lets buyers make independent, best-of-breed choices for software and hardware. That's a compelling vision, but it's also a long-term one.

To realize that vision, we need rich and open interoperability. I must mention "standards," but we all know that there are standards that fail to enable true interoperability. In purely software environments, open source can often simultaneously enable interoperability and API innovation better than standards, which typically move more slowly than open source software. On the other hand, insisting on end-to-end open source can potentially stifle innovation by discouraging investment.

I'll talk about interoperability and openness on April 2 in an Interop Las Vegas session: "How SDN Ready is Your Network Infrastructure?" The core promise of SDN depends on efforts toward openness, so I'll discuss OpenFlow, Open vSwitch, OpenStack, and OpenDaylight. If time permits, I may even comment on OpenCompute and OpenContrail, and perhaps some other OpenWhatsit™ (JK!) that pops up by then.

A good discussion of interoperability must include conformance testing, too. The ONF's Forwarding Abstractions working group's spec, which will be nearing release by the time of Interop, creates a framework that allows industry participants to precisely define and share specific SDN functionality "profiles" well ahead of SDN runtime.

The profiles, called table type patterns (TTPs), can be defined by switch vendors, application vendors, customers, or other interest groups such as standards bodies (including ONF working groups) or industry consortia. TTPs dramatically reduce the scalability and interoperability challenges that are otherwise present with arrival of OpenFlow 1.3-enabled products. My talk will provide more details on how TTPs actually deliver those benefits. You can get a mini-preview of TTPs from these slides at SlideShare.

My session wouldn't be complete without some mention of some controversial subjects like SDN washing and commoditization too, but perhaps it's better if I leave the provocative topics for you folks in the audience. I'm looking forward to sharing my views at Interop Las Vegas, March 31 - April 4. Save the date, and I will see you there.

Join top-rated speaker Ivan Pepelnjak for a half-day workshop Designing The Virtual Network For The Software-Defined Data Center. Ivan will cover the pros and cons of core SDN components, explore overlay virtual networks and tunnel protocols, and help you select optimal networking technology for a private or public cloud deployment. Register now for Interop Las Vegas. Use the code SMBLOG to get $200 off the current price of Total Access and Conference Passes.