Despite the promise of SDNs and the filled sessions at Network World's Open Network Exchange conference this week, lots of questions remain on the technological trend virtually everyone says will redefine networking.
First, what is this "Daylight" open source SDN controller Cisco, IBM, HP, NEC and Citrix are reportedly developing? SDNCentral broke the story last week that the companies are forming an open-source foundation, modeled after the Apache and OpenStack foundations, and plan to unveil the Daylight controller project around the time of the Open Networking Summit conference in April.
Other questions swirling around the Open Network Exchange conference were: is anyone working to standardize the northbound API between controllers, and orchestration systems and applications? Currently, those APIs are proprietary and/or various versions of RESTful or Java APIs.
Also, OpenFlow is the most popular southbound API between controllers and switches; but is there work underway to standardize a controller-to-controller API for redundancy and failover and scalability requirements? Currently, no there is not, participants agree.
And lastly, can SDN, with its promise of network virtualization, emulate the models of server and storage virtualization that came a generation before it? And can those models serve as successful schematics for how network virtualization should unfold?
"Virtualizing the network is going to be the next big thing," says Casimer DeCusatis, distinguished engineer in IBM Systems Networking. "It's going to change the playing field a little bit. Those that have been successful in networking are not necessarily going to remain successful. The only way this works at all is if it's based on open industry standards and interoperability."
DeCusatis would not comment on the Daylight project or the accuracy of the SDNCentral reports. Nor would Don Clark, director of corporate business development for NEC; Sarwar Raza, director of Cloud & Software Defined Networking at HP Networking; and a Cisco spokesperson.
But Daylight sounds a lot like what Juniper was referring to when it disclosed an effort to coalesce the industry around an open source controller to serve as a third "standard" alternative to those from Cisco/Insieme and VMware/Nicira. Juniper backtracked a bit from that when it divulged its overall SDN strategy earlier this year, saying that its vision had "evolved" since then to a belief that open source may not be the best source for core controller functionality.
This week, Juniper would not comment when asked if it would join or support or participate in the Daylight effort, but said it dovetails with its own SDN principles. From a company spokesperson:
As you know, we believe industry collaboration and a move toward standards will be key to realizing the potential of SDN and we are actively involved in key industry initiatives that will play a role in this effort. Juniper's approach to SDN includes six principals aimed at helping enterprises and service providers address their networking challenges. A large part of SDN's success, and the fifth principal in Juniper's vision, will hinge on standardizing protocols for interoperable, heterogeneous support across vendors, providing choice and lowering cost.
We are not going to comment directly on the effort described but it is consistent with the principles of SDN we've discussed over the past few weeks. We believe industry collaboration/standards will be key to realizing the potential.
Sources say the Daylight effort will not stop with the companies already identified as participants. The roster is expected to expand by the time it's announced in April. They've also heard rumors it's being led by David Ward, Cisco's Service Provider Chief Architect, Chief Technology Officer, but that could not be confirmed.
But a padded roster doesn't necessarily mean all are behind the effort. Some may want to just witness the progress and learn from it; others may want to try and blunt its momentum.
Jim Metzler of consultancy Ashton, Metzler & Associates, and moderator of the Open Network Exchange conference, noted the same dynamic in the Open Networking Foundation, which has 90 user, vendor and service provider customers ostensibly rallying behind OpenFlow:
"Some are pushing (the effort), some are watching it and some are slowing it down," he said. "It's like herding kittens."
Until the consortia sort it all out, users at the Open Network Exchange still have open questions about SDNs: implementation, use cases, and benefits.
"What are some of the inhibitors" of SDNs, one participant asked, before rattling off a litany of potential obstacles, like education and training of those with CLI-intensive skill sets honed over decades; vendors not adopting standards fast enough; co-existence of "pure" SDN switches and networks with those supporting hybrid implementations; ambiguity on how latency will be handled in controller-to-switch interactions; production proof points; and justification of its value to business.
"How do you sell it internally?" the participant asked. "How do you make the case that it's not bleeding edge, but a lot of dollars that could be saved?"
Others wanted to hear more about what wasn't discussed in vendor presentations at the conference.
"We haven't talked about future ASIC development going forward," another participant said. "What's going to happen in ASICs to facilitate SDN? What about name and directory service tie-in? How is failover handled, if at all? There was nothing mentioned about QoS; and very little was said about the enterprise - it was too data center focused."
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