OpenDaylight, Hydrogen, and the Vagaries of Open Networking
Open source and open standards are becoming increasingly important in the SDN sphere, but openness isn't a magic bullet.
Open source is emerging as a key requirement for software defined infrastructure, particularly when it comes to the network layer. But how open does SDN really have to be? And do we run the risk of integration issues and other compatibility problems even among systems that share the same open source architectures?
In theory, open source and open standards should alleviate these concerns. But any IT expert will tell you that open systems do not guarantee plug-and-play compatibility. Quite often, deployment of open platforms requires a lengthy integration phase, which can even require input from outside specialists, adding to the supposedly lower cost of open hardware and software.
Software defined networking, however, seems to have embraced open standards from the beginning, namely through the OpenFlow and OpenStack protocols. And the OpenDaylight Project, backed by many of the leading proprietary systems developers, recently released its Hydrogen platform. OpenDaylight Hydrogen aims to provide a fully open standard for everything from the SDN controller to the OpenFlow plugin, the service abstraction layer and even configuration and management tools. In short, the platform appears to extend the open southbound capabilities of the OpenFlow protocol to higher-level northbound functions, once the province of proprietary systems from Cisco, Juniper, Big Switch and others.
Of course, how open can a standard be when the organization that created it is funded largely by the vendors the standard would undermine? Gartner’s Andrew Lerner says that was a key concern of his when OpenDaylight was launched. He is now cautiously optimistic about the Hydrogen release because it is the first usable code to come from the organizations – a sign that the group is not simply a delaying tactic to give top vendors a chance to co-opt the open SDN market.
Is Hydrogen any good? Well, it’s too early to say, but the same can be said for rival systems like OpenContrail and Floodlight as well.
Let the doubters doubt, says the Linux Foundation’s Jim Zemlin. Linux faced widespread skepticism when it first hit the scene. Now it is difficult, if not impossible, to imagine hyperscale operations like Facebook and Amazon without it. Hydrogen, Zemlin noted, is the sum total of more than 150 contributors who have written upwards of 1 million lines of code.
OpenDaylight is not the only open SDN format in town, though. Dell recently inked a deal with Cumulus Networks to incorporate the latter’s Linux-based operating system in a bid to challenge Cisco, Juniper and others for the rising cloud provider market. The companies say that by going with a straight-up Linux approach, organizations will be able to integrate SDN architectures more easily with legacy infrastructure and avoid both the proprietary approaches of leading vendors and the scale-out original design manufacture (ODM) approach championed by large providers like Google and Facebook. Dell is offering the Cumulus package on the S6000 and S4810 ToR switches due to hit the channel in a few months.
There is no reason why a Dell/Cumulus device could not sit comfortably within a broader Hydrogen environment, but it does point up the fact that there are numerous levels to the SDN stack, and determining exactly what open solution is right for each one could prove tricky. And there is always the comfort of knowing that a proprietary system is more likely to extend key features end-to-end and will probably (probably) provide a shorter, smoother deployment process.
Is that worth the risk of vendor lock-in that open source is so desperate to avoid? That’s up to the CIO to decide, but when it comes to networking, the importance of interoperability of all components cannot be overstated.
Open source groups like OpenDaylight say they can enable that kind of broad integration as well. But like their proprietary rivals, they now need to prove it in the marketplace.
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Arthur Cole covers networking and the data center for IT Business Edge. He has served as editor of numerous publications covering everything from audio/video production and distribution, multimedia and the Internet to video gaming.