"The big question is do you have to buy into SDN whole hog -- jump into the deep end first -- or can you make this transition in a more gradual fashion?" Eric Hanselman, chief analyst at 451 Research and SDN track chair for Interop Las Vegas, said in an interview. "Fortunately, it's not something that you have to do all in one shot."
Companies can get started on the road to SDN by automating pieces of their network environment through virtualization. "Most organizations have gotten to the point where they're automating some of the simple networking technologies, like VLANs, but those basic techniques need to take a step up," Hanselman said.
Network overlays are a good choice for stepping up automation, he said. "Overlay technologies are a great way to enhance connectivity, but not yet cause disruption in the existing network operation."
A network overlay is an SDN option in which tunnels are set up between virtual switches inside hypervisors, networking expert Greg Ferro wrote in a recent InformationWeek report, "Overlay Networking: An Introduction."
"While the tunnels make use of the physical network to send packets, they don't have to configure switches to get traffic to its destination," he wrote. "By contrast, other SDN approaches use methods such as OpenFlow to program switches."
For organizations interested in migrating to OpenFlow-based SDN, the Open Networking Foundation's migration working group recently made available a paper that describes SDN use cases and best practices for SDN migration. The paper includes three use cases: Google's inter-data center WAN, NTT's service provider edge, and Stanford's campus network.
[Read about the security challenges that come with software-defined networking in "Beware SDN Security Risks, Experts Warn."]
The level of readiness for SDN depends on an enterprise's organizational maturity in terms of how much automation and orchestration they already have in their infrastructure, Hanselman said.
"To really leverage SDN, you need some level of sophistication in orchestration. ...If you're not already starting to automate deployment of compute and storage resources, there's not much point in starting to automate the network," he said.
SDN's Impact On Networking Pros
All the movement toward automation naturally has some network engineers on edge. Networking practitioners are wondering if SDN will put them out of work, Hanselman said.
He urges network pros to embrace the transition as something that can help them play a bigger role in an organization. Otherwise, they risk being left behind.
"So much of what has been guiding networking for so long has been the firefighting -- all of the modifications, all of the odds and ends of troubleshooting that occupy your average networker's day," he said. "By integrating with more sophisticated management, SDN can get rid of the more repetitive day in and day out drudge work."
To make this transition, network engineers will need to be better versed in the various aspects of IT operations, Hanselman said. Learning some programming skills -- for instance, Python -- can go a long way in terms of understanding the steps toward greater automation.
"We've spent a lot of effort getting really good at CLI wrangling," he said. "Now, we need to set the console cable aside and work within management systems and scripting capabilities to really understand in greater detail the higher capabilities of our various platforms."
Anxiety aside, many organizations appear to be marching ahead with SDN plans. An Enterprise Strategy Group survey of 300 IT pros in charge of networking found that two-thirds of the companies polled are committed to SDN as a long-term strategy. Twenty-seven percent said they've actually begun implementation.
"For better or worse, we've come through a period of tremendous hype ... What's happening is people are starting to understand there's value of moving beyond the hype," Hanselman said. "They're understanding there is something other than all of the flash and grand claims -- the fact it can really work and help operations work more efficiently."
[Eric Hanselman will moderate a panel discussion on the changing roles of network pros as virtual networks, SDN and automation makes inroads in the enterprise. Don't miss "Will SDN Make Me Homeless?" at Interop Las Vegas March 31-April 4. Register today!]