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The promise of software defined networking

John Dix | July 1, 2013
SDN is still an emerging technology. We take a look if it can live up to its promise of redefining networking.

Nicira, which, besides Big Switch, was one of the other SDN early birds to spring out of the Stanford labs where SDN was conceived, is focused primarily on virtual networks, what some call overlay networks. That made it a good fit for the king of the virtual machine world, VMware, which shelled out $1.2 billion to acquire Nicira in 2012.

But aren't companies that are focused primarily on virtual networks artificially constraining their opportunity? Lippis says, "If you look at the number of virtual ports to physical ports, there are more virtual ports now and the number is growing a lot faster than physical ports, so [VMware/Nicira] believes they're focused on the high-growth part of the market."

Ultimately, however, SDNs will need to span the virtual and the physical if buyers are to realize the biggest return, and they will need to span the data center and the WAN.

Early ONF backer Google, for example, has already deployed an SDN WAN backbone that is paying dividends.

"The biggest advantage is being able to get better utilization out of our existing lines," says Google Principal Engineer Amin Vahdat. "The state-of-the-art in the industry is to run your lines at 30% to 40% utilization, and we're able to run our wide area lines at close to 100% utilization, just through careful traffic engineering and prioritization. In other words, we can protect the high-priority traffic in the case of failures with elastic traffic that doesn't have any strict deadline for delivery." 

Of course few organizations have the resources that Google does (it built the devices used to control that backbone), so much of the focus today is, in fact, in the data center.

Early benefits
Mark Leary, chief analyst at The First Tracks, says one of the earliest benefits of SDN will be simplifying networks. "Consolidating around a central control structure allows for greater automation. That's where you can see a lot of immediate impact."

But how do you get there from here given the huge investments in legacy gear?

"Incremental adoption is the key for success," Leary says. "The beauty of some SDN solutions is they are compartmentalized. You can drop them into some part of your network to reduce complexity and see immediate benefit. And then once you've expanded on that and finished simplifying the overall structure, SDN is about improving the dynamics, by, for example, allowing the network to adapt to load."

Lippis says one benefit mentioned by many early adopters at the first ever ONUG SDN users group meeting in Boston was network visualization. "What some companies are doing is using low-cost 10 Gigabit Ethernet switches with OpenFlow interfaces to connect mirror ports on data devices to analytic service nodes. That drastically lowers the cost to gather traffic and, since the costs are lower, gives you the ability to tap into more places so you get a larger view."


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