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SD WAN: How to choose between DIY and a Managed Service

SD WAN makes your network look simple, but it's complex underneath

SD WAN prides itself on simplicity, presenting you with a simple view of your network, and promising to make it simple to manage. But beneath that simple view lies a network that is just as complex as it was before, probably more so.

While the overlay makes things look simple, there is a lot going on under the hood. And while an SD WAN user interface makes things easy to change, the implications of those changes can be far-reaching.  This creates new risk for teams who previously delegated such changes to the management service.

Turning to the underlay, this will tend to become more complex with SD WAN.

Why more complex?

Among other things, the underlay can be more complex because SD WAN encourages you to:

  • Have multiple circuits at each site;
  • Mix internet with traditional network technologies;
  • Route traffic dynamically.

With SD WAN, the underlay still needs to be designed and sized to support the traffic and performance that your applications need.   When things go wrong, the problem still needs to be identified and rectified.  With complex and intermittent problems, this work can be non-trivial, and it's often outside the scope that SD WAN can deal with.

To illustrate, a large global geo-science business recently reported that their new SD WAN suffered from poor latency.   The SD WAN overlay presented global connections as single hops with low latency. 

However, this masked the reality of multiple physical hops and sub-optimal transatlantic hops that led to well very long total latency. 

It took traditional skills to identify and fix this problem, and at best, SD WAN didn't help because it obscured what was going on.

The automatic gearbox in your car presents you with a very simple experience, but it hides great complexity.  SD WAN presents a simple view of your network, but it, too, hides great complexity.

Complexity means that, for the whole network to perform well, network expertise is still required at design stage, during deployment, during post-deployment tuning, and when complex problems arise in-life.

Again, someone has to do that work, and the question of who does that work goes to the heart of your choice about DIY vs Managed SD WAN.