LAS VEGAS -- Interop -- One concept taking shape around software-defined networking (SDN) is the idea of applications knowing more about the network. But how much should they know, really? That was one of a few general SDN topics discussed during a Wednesday morning keynote panel with Broadcom, Microsoft and VMware -- a group that arguably represents the vanguard of what networks are becoming. (See Virtualization Takes the Stage at Interop.) It's a position even network incumbents share, but it's still a bit vague right now, and it opens questions such as how to control how much information certain applications can get. This goes beyond the obvious security question and deep into network operations. After all, under SDN, "applications become part of your network infrastructure," said Rajeev Nagar, Microsoft's group program manager for Windows core networking. At the same time, there's a valid argument to not go oveboard with this, said Martin Casado, chief networking architect with VMware, alluding to some problems he'd had in his supercomputing days. Attempts to let applications know more about the hardware sometimes ended up killing off the application -- "too much information" exists in the software world, too, it turns out. "There does have to be some interaction," he said, but "the less that the application has to know about the network, the better it is for everyone." The other two panelists didn't completely agree. Many applications truly don't need to know that much about the network, Nagar said, but then again, "the control and management applications -- certainly they're going to be very aware of the network, and they're going to interject themselves into the network." "There's always going to be network visibility that will impact network performance," said Rajiv Ramaswami, executive vice president of networking at Broadcom. "You don't need to know bits and bytes, and you don't need to provision every port, but you do need abstractions." Most of the time, the panel dealt with the bigger questions around SDN and how it might or might not change the world. SDN has come to be thought of as a "single point of impact," said panel moderator Eric Hanselman, an analyst with 451 Research. "It creates an expectation that the network has to be saved," he said. But really, the underpinnings of SDN are in place. Casado reiterated his observation (previewed yesterday on Light Reading) that large data centers have already evolved into a simple Layer 3 network surrounded by computing platforms that handle many of the networking functions -- a very SDN-friendly shape. "These [data centers] which have been around 10-plus years already look like what we attribute to SDN," he said. "It's living among us already. " As a side note, he thinks the reason the large data-center operators did this was to gain speed and agility, which could then be said to be the primal drivers of SDN. The panel didn't make the leap of logic that their work is going to displace the equipment vendors such as Cisco and Juniper (which got the keynote spots on either side of this panel). Casado, in particular, thinks it's too early to make that call. But he does agree that the rules are changing. "It's pretty clear that the voices of the dialogue have changed with different members. For example, we have customers that have direct conversations with the silicon players or with us, the software vendors," Casado said. For more

— Craig Matsumoto, Managing Editor, Light Reading