Be prepared for SD-WAN implementation complexities

Potential software-defined WAN customers should be wary of oversimplifying the technology.

As more enterprises take on an SD-WAN implementation and talk about their successes, it can be tempting for other companies to rush into a decision thinking it's easy, said Errin Mahnken, senior manager of strategic business solutions at Tata Communications, who commented about SD-WAN on the tradeshow floor at the ONUG conference in New York City this week.

"A lot of customers tend to oversimplify things and look at it from the perspective of 'All we have to do is plug in the internet and we'll be fine'," Mahnken said. In reality, it's a bit more complicated.

"When you have traditional routers, it's like playing checkers -- it's one way or the other," he added. "With SD-WAN, it's more like 3D chess."

Just like different chess pieces have different rules and can move in different ways, so do SD-WAN components. This is where Mahnken said it's important for enterprises to consider the requirements for each application.

One of the first steps potential SD-WAN users should take is to ensure they have the internal staff to support the SD-WAN implementation and the long-term maintenance. If an enterprise lacks the internal expertise, it should choose a support model in which someone -- like a managed service provider -- provides the support instead.

The next step, according to Mahnken, is to choose a recommended deployment model -- such as rip and replace or a slow migration -- and understand how to implement it.

"We recommend customers migrate slowly over to make sure they take into account a lot of the nuances they may have," he said. This process typically starts with the headquarters or main data centers and then progresses to additional sites.

By migrating slowly, enterprises have a better chance to tackle any challenges and nuances that come their way. Customers should go into SD-WAN implementation expecting to run into issues, Mahnken added.

"With every plan -- however well you thought it out -- as soon as you go implement it, you're going to run into those nuances," he said. These challenges can be glitches in software -- like an incomplete version of Border Gateway Protocol -- or a misconfiguration on the implementation engineer's side. The bugs "tend to crop up unexpectedly at the worst times," he added, and happen more often than people are willing to admit.

While it might not be possible to avoid all software glitches during SD-WAN implementation, he said the best defense is to make sure the people who are implementing and configuring the software are trained properly.

"It's not as simple as everybody says -- to push a button and move on," Mahnken said. "Zero touch, from what I've seen, is not as zero as it could be. There's still a lot of configuration."