"The industry has been looking for the reinvention of the WAN for 25 years," Zeus Kerravala, principal analyst with ZK Research, told eWEEK. "It was designed for client/server technologies. Now we've got mobile traffic, a lot more cloud traffic, a lot of PLP [packet layer protocol] traffic. … The architecture we have just doesn't work now."
Software control of the network enables greater ability and flexibility, Kerravala said. Even now, making changes in the WAN means having to go from box to box, a process that can take months. That effort can be reduced to hours or days through the adoption of SD-WAN technologies.
It also can drive down the costs of networking by enabling businesses to complement expensive MPLS connectivity with more affordable alternatives, creating hybrid environments where the best options can be used via automated intelligent routing. WANs can more easily be connected directly to the Internet, rather than having to first run through a central data center, reducing complexity and simplifying management.
It's bringing networks up to par with servers and storage, which already have been virtualized, according to Paul O'Farrell, senior vice president and general manager of the SteelHead, SteelFusion and SteelConnect (for SD-WAN) businesses for Riverbed technology.
"Today you can spin up servers with applications running in hours or minutes," O'Farrell told eWEEK. "But you can't do that with enterprise networks. … [SD-WAN] is all about turning network management from being kind of a fairly anachronistic skill based on an anachronistic approach to IT management to dragging it into the 21st Century."
Michael Wood, vice president of marketing for VeloCloud, described current architectures as "proprietary," "closed," "static" and "rigid." They need to be open, agile, automated and dynamic, Wood told eWEEK.
The key driver behind the push toward SD-WAN is where most applications are now located, according to Gartner analyst Andrew Lerner. Before, most workloads were in the data center, and businesses could use MPLS for connectivity. However, with the rise of software-as-a-service and the growth of businesses like Salesforce.com and Workday, that's changing.
"A good portion of apps no longer are in the data center," Lerner told eWEEK. "They're in the public cloud. MPLS wasn't made for that. … It's all about the cloud. It all starts with the cloud."
The SD-WAN market is still in its early stages, but it is expected to grow rapidly over the next several years. It is already a crowded and competitive field. Gartner is predicting that while about 1 percent of enterprises currently are using SD-WAN technology, the number will increase to 30 percent by the end of 2019.
IDC analysts in March said they expect the market to grow to recent survey by IHS Infonetics analysts found that 65 percent of campus LAN respondents have started or expect to start lab trials by the end of 2016, and 77 percent say they would go into live production by 2018. The initial use cases for the technology will involve virtualizing physical WAN links and optimizing application traffic flow, they said.
In some respects, many of the concepts of SD-WAN aren't new, Lerner said. Encryption, zero-touch provisioning, overlay networks and subscription pricing have been around for a while. But SD-WAN offers them together in a new way that addresses issues with which WAN businesses are wrestling.
He likened it to SUVs and a small smart car. Both have essentially the same elements—engines, tires, steering wheels, seats, bodies, etc.—but the smart car care is better suited to address the challenges of driving in a city.
A Crowded Field of Vendors
The space is attracting a broad range of vendors, with almost two dozen in play now.