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

SD WAN is an overlay; you still need an underlay

The devices and software in an SD WAN network are known as the overlay. It's an overlay because it sits above your MPLS, VPLS, Internet and other connectivity, which in turn is known as the underlay.

When you move to SD WAN, this underlay does not go away.  It still needs to be procured, installed, configured, monitored, repaired, changed, billed and paid for.

That means managing carriers (who each have their own names, definitions and processes for services) placing circuit orders, project-managing installations, and dealing with faults. That's on top of designing the underlay in the first place, monitoring it and maintaining its performance. 

Someone has to do that work.  The question of who does that work goes to the heart of your choice about DIY vs Managed SD WAN.

Self-Driving WAN

One major vendor positions their SD WAN as Self-Driving WAN, because of its ability to adjust the way that it runs the network to meet your business intents. 

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That is a great analogy, especially if it’s self-navigating, too.  If we upgrade to a self-driving car we could just imagine being able to dispense with the chauffeur!   

If a self-driving car needs no chauffeur, does a self-driving WAN need no management service?

Well, there’s more to a running a car than just driving it around.  If we fire the chauffeur, then we still have jobs to do to keep our self-driving car fuelled and on the road.   

What will still need doing?

With a self-driving car, we'll still have to buy fuel from the same filling stations that we take for granted today. If it’s an electric car, we’ll still have to deal with all the charging networks and their accounts.   Without the chauffeur, we'll now need to get out of the car to fill up and to pay ourselves. 

Really? Would that be so bad?

No, not on the face of it.  However, back in the real world we buy a lot of things from carriers, and we know that’s not always pain-free.  So...  what if we fired the chauffeur who had been handling our fuel and our charging, and then we found that

  • Every fuel station has a different process and a long lead time to get the fuel each time? 
  • They each need you to set up a separate account, and send you a separate bill?
  • They ask you to pay in different currencies – with some not offering to speak your language?

That's a lot of hassle. If our chauffeur had been dealing with all of that for us, then we might miss him when he's gone.

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What about the things that other people do for us?

We also need to keep our new self-driving car on the road.

We still need a garage, a mechanic and a spare parts department.
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Will still need a breakdown company for when it won't start in the morning, and a recovery truck and body shop to pick up the pieces after a crash. DIY vs Managed SD WAN-03

And we need someone to deal with all of those suppliers, and with all of their admin.


Dispensing with a managed service is like firing the chauffeur, the garage, the mechanic, the spares supplier, the breakdown company, the recovery truck, the body shop - and the manager who administrates all their work for you.

If we had to pick up all of their jobs, then we may have little time left to use the car!

So, this begs some questions:

  • What are all the jobs involved in running your WAN today?
  • Who is doing them today?
  • Who do you want to have doing them after you move to SD WAN?

By the way, when you pick up your new self-driving car, you can’t just sit in the back; you’ll be behind the wheel to check everything is ok, start the engine, set up the Sat Nav and keep a watch out for problems.

However, if you keep the chauffeur and the rest of the support crew, you can safely get in the back and get on with some real work while the car gets you quickly and reliably to your destination. 

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That's one reason that Enterprise WAN managers use a managed service; so that they can focus their scarce resource on adding value rather than running the WAN.