Making Heads or Tails of SDN Standards: From OpenFlow to OpenDaylight and More

To paraphrase Abraham Lincoln (which you admittedly don’t often get to do in a technology blog), “God must have loved standards because he made so many of them.”

That sentiment is nowhere more evident than in the field of software-defined networking, a field in which recent standards news has been flying with the speed of software decoupled from hardware hurtling across Ethernet. The question is, if you’re interested in SDN, which standard should you be paying the closest attention to? Hint: the one that’s going to keep customers’ best interests in mind – not the vendors’.

Let’s recap quickly:

OpenFlow, managed by the Open Networking Foundation, is an open-source communications interface between the control and forwarding layers within an SDN architecture. Its supporters include most major networking vendors, among them Alcatel-Lucent/Nuage Networks, Arista, Big Switch, Brocade, Cisco, Extreme Networks, Hewlett-Packard, and Juniper. (It is odd to find Big Switch on that list, given that it has also created its own open-source software for creating SDN networks called Project Floodlight.)

OpenDaylight bills itself as “an open platform for network programmability to enable SDN and create a solid foundation for NFV for networks at any size and scale.” (For more on the confusion between what’s SDN and what’s NFV, see my previous post It counts many of the same network vendors among its supporters as OpenFlow.

OpenStack is part of the mix by virtue of the fact that it’s an open source cloud computing platform, and virtualization is a key component of cloud computing. Its supporters include both enterprise vendors and networking vendors; among the latter: Alcatel-Lucent/Nuage Networks, Arista, AT&T, Avaya, Cisco, and Hewlett-Packard. Because of the crossover between virtualization and cloud computing, you get announcements such as the one from OpenDaylight in early October that it now integrates more easily with OpenStack.

Reading the definitions, it’s admittedly hard to figure out the difference between OpenFlow and OpenDaylight. That’s why it’s necessary to do a little digging into who’s behind each one and why. NetworkWorld’s Jim Duffy provided a great perspective when OpenDaylight was first unveiled last year. Duffy rightfully noted that it was a vendor consortium rather than a truly open user community. He quoted Gartner analyst Joe Skorupa as saying, “We're skeptical of this effort for several reasons. Unlike the ONF, this effort is controlled by large vendors and has cut out the voice of the consumer. In private conversations with a number of vendors, they have expressed the same concerns. They may be members, but clearly aren't supportive.” Oops.

Case in point: as Scott Fulton III reminded us in his recent DataCenter Dynamics article entitled The Yellow Brick Road to SDN, Cisco is promoting its own OpFlex alternative to the OpenFlow protocol. Fulton writes, “OpFlex serves as software that defines a network, all right, so long as that network consists of physical switches — the product that continues to butter Cisco’s proverbial bread.” Is the Op of OpFlex meant to connote open, even though it’s … not?

To muddy the waters even further, the Linux Foundation, which manages OpenDaylight, announced a new project in September, Open Platform for NFV (OPNFV). As described by Steven J. Vaughan-Nichols in ZDNet: “The initial focus of OPNFV will be on building NFV infrastructure (NFVI) and Virtualized Infrastructure Management (VIM), leveraging existing open source components where possible.” The latter include OpenDaylight, OpenStack, Open vSwitch, and the Linux kernel. So there you not only have an impenetrable bowl of alphabet soup, but an echo of the old department store commercial where the frenzied shopper is pressing her face to the window saying, “Open open open.” (The department store was Mervyn’s, which did business in ten states and is now, perhaps tellingly, bankrupt.) Saying it doesn’t make it so.

Interestingly, Vaughan-Nichols also noted, “Not everyone who supports NFV is on board with this new effort. Telefonica SA (an early open source NFV advocate), BT, and Verizon are all noticeably absent.”

It’s clear what’s going on here. As someone who lived through the Unix religious wars (remember OpenLook and Motif?), I’ve seen this before, and it’s all too familiar. Vendors are jockeying for position and protecting their territory. They never seem to learn that doing so simply postpones the inevitable moment when they have to retract their elbows and actually create something that adheres to the standards that the users want. The sooner users demand that the vendors stop posturing and creating reliable, interoperable products, the sooner the industry can move forward. That’s the only action that benefits both customers and vendors.

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