"SDN is just a tool set," he continues. "Network virtualization is an actual solution. It's a product that you sell. And it solves many of these problems. It will decouple the security policy from the physical topology. It natively supports mobility. It allows for dynamic service interposition. It natively supports isolation. Whether or not you build network virtualization with SDN is an independent question. You can certainly do it without using SDN; I just question whether you'll have the guarantees you need on the scale you'll need. My sense is, without SDN you can't do virtualization at scale with guarantees. But the solution that will change the operational model of the enterprise is virtualization."
HP agrees with that perspective from Nicira: OpenFlow and SDNs are just tools to enable the real value of programmability, which are applications like network virtualization and granular policies for different use cases -- like managing the bring-your-own-device (BYOD) phenomena in enterprises. HP earlier this year rolled out 16 OpenFlow-enabled switches for the enterprises that interoperate with controllers from vendors Big Switch, NEC and NTT, as well as open source controllers like NoX, Beacon, Floodlight, and Trema.
HP also demonstrated its Virtual Application Network orchestration capabilities at Interop in May.
"SDN is a capability and then there are the network applications that run on top of it: network virtualization, BYOD policy, or things of that nature which is what people are actually using," says Saar Gillai, CTO of HP Networking. "In network virtualization, SDN can help you in doing some of the overlay tunneling but there's other things you need to provide to create that capability. SDN is a technology that can be leveraged to provide some unique applications but in and of itself it's just a technology."
OpenFlow and SDN's real value comes from what it enables. Network virtualization allows enterprises to share a common physical infrastructure with different attributes among multiple organizations, says Karl May, CEO of Vello Systems, a maker of OpenFlow and SDN cloud switches for enterprises.
With SDNs, customers build an abstraction of the physical infrastructure to use it for a combination of production and test networks.
"That is greatly undersold when people talk about SDNs," May says. "That's a very valuable element of the SDN architecture."
The programmability afforded by OpenFlow and SDNs enable applications to define the behavior of the network and provide them with a level of deterministic performance, May says. This is appealing to enterprise customers with very high performance computing or Big Data needs, he says.