"There's no reason tomorrow it couldn't be an OpenFlow or OpenStack API," Ullal says. "But here's a well-defined interface. Today we do Netconf and XMPP because it was easy to implement, well-defined specs and we had some customer interest there."
Ullal says Arista's EOS will support a suite of APIs for different "use cases" that customers demand. Right now, Arista is detecting initial demand for OpenFlow among research institutions, and in data centers to redirect flows to taps and tap aggregators.
"One new technology does not preclude the pragmatic approach of also enhancing existing technologies," she says with regard to SDNs. "In operational environments where legacy prevails, enhancing existing technologies is even more important than innovation."
Rather than OpenFlow driving SDNs, SDNs will drive OpenFlow, Ullal believes.
"The combination of OpenFlow with broader SDN APIs is vital for OpenFlow to be more broadly deployed," she says.
Big Switch's Forster says SDNs would not have the buzz or momentum in the market today were it not for OpenFlow. And with myriad APIs each tailored for a specific "use case," that means there needs to be fewer to program to.
"In many of the programmability approaches that vendors are trying the APIs become so incredibly specific that it's simply not profitable for a third-party vendor -- and really barely worth the customer's time -- to write on top of these incredibly specific APIs," he says. "There's a fairly broad consensus of folks realizing that unless there's a baseline of standardization, there's some that will never create an ecosystem of third-party applications for this."
With respect to XMPP, Forster says it's "clever" but doesn't mask the complexity of automation scripts written to it.
"XMPP doesn't let you write a Perl script that can roll back (unintended commands)," he says. "The Perl scripts that you write on top for automation still end up being pretty complicated."
But what's not debatable is the visibility OpenFlow is bringing to SDNs, and vice versa.
"OpenFlow is critical, and not because it's the answer," says Andre Kindness, an analyst with Forrester Research. "It's one of the answers. But it's the only one getting a lot of play because there are a lot of communities working on it. It's a huge amount of brainpower working on it. It's driving a lot of discussions and new ways of thinking. We got a good horse race going on here."
Read more about lan and wan in Network World's LAN & WAN section.