Where are we with respect to SDN? That’s a question a lot of people are asking, and that a lot of vendors are watching. The answer, at least according to my survey this fall, is “We don’t know”, and that’s an important point to consider if you want to understand what might happen in the SDN space in 2013.
I measure “buyer literacy” for a given technology based on their ability to articulate the benefit case for the technology sufficiently to justify a project, and to draw the deployment architecture well enough to be able to engage vendors in purchase dialogs. Based on that measurement, we’re at about 8% buyer literacy in SDN. In the past, a successful market has demanded about a 33% buyer literacy, which says that with SDN we have a long way to go.
Why is this such a mess? One reason is that there are three different models of SDN value being tossed around wrapped in common technology nomenclature. We call “virtual networking” a la Nicira SDN. We call OpenFlow networks SDN. We call vendor-sanctioned software-driven network behavior exercised through traditional protocols (Cisco’s ONE) SDN too. Users, meaning enterprises, rarely understand the distinction much less the “value focus” for each of these approaches. How then could you justify a project? Because of this, SDN for enterprises is very much a defensive issue; if my vendors don’t have an SDN strategy I’m risking stranding assets if SDN takes hold. Blow a kiss at the SDN baby and most buyers are happy (which is why network vendors’ lips are pursed into permanent puckers).
But the big problem in the survey wasn’t the issue of the value proposition; buyers think that either SDN is a cost play or it’s linked to cloud deployment, and both of those things are substantially true even if buyers don’t understand why that is. What the buyer doesn’t understand is how to draw an SDN, how to create a simple functional diagram. If you ask them, the model that emerges most of the time is two blocks, with the top labeled “software” and the bottom labeled “network”. OK, functionally perhaps that’s true, but if you then try to go out and buy your SDN tools, how far do you get by saying “I need software” and “I need network?”
Google’s SDN deployment offers us a vision of the issues of SDN. What Google has is an SDN enclave (a core, in their case) surrounded by “gateway” points. These gateway points talk IP-control-plane to the rest of the network, and take the topology/forwarding information they obtain back to a central point where it’s converted into route policies, meaning preferred paths between points. These aren’t user flows, they’re trunk routes, and they are then converted by an OpenFlow controller into commands that drive forwarding plane changes on devices Google custom-built. How much of this do you suppose a typical enterprise understands? Where are the commercial products that could support these various functional missions?
I’m not arguing against OpenFlow or SDN; you all know by now that I’m a believer. But I am arguing for an end to the totally vacuous discussion we’re having on the subject. Nobody in this day and age is going to make a technology investment for no reason other than to consume a new technology. Nobody is going to buy into an architecture they can’t even block-diagram. We’re creating a fog around SDN, or at least allowing a fog to descend on it, and it’s not just blocking the details of SDN, it’s threatening the opportunity. The vendor who sings this particular technology song very well may have an immense opportunity…if they can get the song heard in the real world, by real buyers.