What Clark Griswold and SD-WAN Have in Common

There is one movie I remember watching with my family during the holidays: “National Lampoon’s Christmas Vacation”. For those who haven’t seen the movie, it stars Chevy Chase as Clark Griswold, a typical American dad trying to survive the holidays with his family and in-laws. Sound familiar?

One of Clark’s favorite holiday traditions is decorating his house with Christmas lights, and like many of us he goes a little overboard.  Clark decorates just about every inch of his house, and, in doing so, wreaks havoc on himself and his neighbors. After days of work Clark brings his entire family out front in the cold Chicago winter for the big reveal, the drumroll proceeds, and to their disappointment not a single light turns on when he plugs them in. Despite countless hours untangling every strand and checking every bulb, Clark has no idea why his lights won’t work. While the rest of the family goes back inside his wife goes to grab something from the garage, and with the flip of a light switch the Christmas lights come roaring to life. Madness ensues as their neighbor’s bedroom goes from night to day, the power plant must add more electricity to the grid to sustain the load, and Clark starts yelling for his family to get outside to see the fruits of his labor. The problem is that just as quickly as the lights turn on, they go off, and Clark’s moment of joy is quickly spoiled. Things were working great, what just happened?

Clark: Russ, we checked every bulb, didn’t we?
Rusty Griswold: Sure, Dad.

Users in the branch office know all too well the problem of things working great for a little while and then going back to normal (slow). While many branch offices are provisioned with multiple WAN links, they often rely on a single MPLS link as the primary circuit with an idle Internet link as the backup, missing the opportunity to take advantage of using the faster Internet link continuously. In fact, most users only ever get to use the faster Internet link when the primary MPLS link goes down. While Internet links offer significantly more bandwidth than MPLS, they are generally idle because of the complexity of trying to route traffic across multiple links. Network administrators would love to move users and their applications over to the faster Internet links; however, the lack of reliable packet delivery over the Internet for latency-sensitive applications like VoIP and video forces administrators to continue relying on slower MPLS links. Like Clark’s wife Ellen walking into the garage and hitting the light switch magically turning on the holiday lights, a network outage can have that same effect for users in the branch office.

When there is an outage of the primary MPLS link traffic generally takes its alternate path across the backup Internet connection. Applications that were once slow because of a congested and oversubscribed WAN link suddenly have 5x to 10x the bandwidth they had before. Web browsing is faster, file shares fly, applications are more responsive, and VDI screen refreshes are instantaneous. Users are happy. No longer left to compete with one another for a limited amount of bandwidth, they can get more done, it feels as fast as the Internet connections they have at home. The problem with this scenario, as is the case with Clark, is that it’s short lived. As the impacts of the outage are reported into IT, network administrators quickly work to troubleshoot and resolve the problem, ultimately fixing the issue — turning off the proverbial light switch redirecting applications and traffic back to the slower MPLS link. The moment of nirvana in the branch is over, but it’s too late; users have experienced the power of an Internet-based WAN. They want to know what just happened, and why things can’t work all the time like they did for those sweet few hours.

Keep the ‘Magic’ Going with SD-WAN

Thankfully, we no longer have to live in the dark ages of an active/passive WAN topology. As more businesses begin to realize the performance and availability broadband can bring to their branch users, they are increasingly looking at how to augment or replace their MPLS networks with the Internet. For many users those Internet links are already in place, it’s just a matter of figuring out how they can easily leverage them together with MPLS. Software Defined WAN (SD-WAN) enables enterprise network managers to easily combine any combination of transports simultaneously, thereby simplifying setup and delivering greater performance to end users and applications. Internet links that once sat idle at the branch office can now be continuously “lit up”, drastically improving the amount of available bandwidth for users. With SD-WAN, administrators can easily create policies that allow latency-sensitive traffic such as VoIP and video to continue running across the MPLS link while other traffic routes over the faster Internet connection. What would have been nearly impossible to do just two years ago can now be simply implemented across the entire WAN.

As you gather with your friends and family this holiday season, try not to forget about your users in the branch office. Like Clark, many of them have been left wondering over the years why things occasionally work so well, only to return to normal. With SD-WAN it’s easier than ever to enable multiple active forms of connectivity for better performance, and to finally leave the lights on for your branch office users. And deploying an SD-WAN beats Clark’s free subscription to the jelly-of-the-month club anytime.


Image credit: travis (flickr.com) / CC-BY-ND 2.0