How to Approach an SD-WAN Migration

May 31, 2018

Migration from a traditional legacy WAN network to a next-generation SD-WAN based network that uses for example a mixture of IP private links, MPLS/VPNs etc, is the latest project of epic proportions to baffle network infrastructure teams. I say this not only because SD-WAN’s my area of specialism, but also because I believe it’s so important for you to understand how big an issue SD-WAN migration can be.


The benefits of SD-WAN are great, but the main question everyone wants to answer is, “How quickly can we transform our network from where we are now to this next-generation status?”. I’m sure we’d all like to know the real response, but my advice to you is that if you try to do things too quickly, it’ll take you much longer in the end. The bottom line is that if you fail to plan an SD-WAN migration thoroughly and make mistakes, it could end up being very costly to your organisation.

Usually, vendors or service providers have their own best practice ways of carrying out migrations, but will leave it to you to both come up with your own design beforehand and deal with the remainder of transformation steps afterwards. That arrangement typically works fine where relatively straightforward projects are concerned, but SD-WAN is going to completely change your WAN – and your WAN is a critical asset that you can’t afford to be without. You therefore need to make sure you fully de-risk an SD-WAN migration project from an end to end transformation point of view, and that includes those migration design and transformation stages. At the end of the day, your aim must be to manage risk, which requires thorough design, testing and planning.


Now please don’t be offended when I say that technical people aren’t the best at managing risk. It’s because they very quickly end up in the mode of fixing things, and during a migration you don’t want to end up there. To avoid this, everyone needs to know exactly what needs to be done and what’s going to happen at every stage of the migration process. And of course, if things don’t go to plan, you need to be able to execute a clear rollback process and then understand why.


The ultimate migration goals are to manage risk, keep your TCO low and make the SD-WAN migration time as short as possible. I often use this diagram to explain how to keep SD-WAN migration under control:


SD-WAN Migration & Transformation


From a business point of view, you have your PMO (Present Method of Operation), which is your traditional legacy WAN network, and want to move to a position of FMO (Future Method of Operation), with a lower TCO and good ROI. The steeper the line, the faster you’re going to get there. But it’s unrealistic to assume that, in real life, you’d have all the Capex and Opex funding available instantly to be able to achieve a transformation to SD-WAN overnight. You therefore need to control the cost part properly, otherwise the yellow bubble in the middle will end up getting bigger and bigger. By eliminating the bubble, you get closer to an ideal transition.


It might sound obvious. Based on the graph above, SD-WAN migration should work by allowing you to roll things out quickly without any downtime or issues. Avoiding network downtime is so important as it can sometimes cost the business more money than an SD-WAN migration itself. For example I’ve known businesses that have suffered network downtime for more than a few hours and that’s really when negative financial impact starts getting serious. At Teneo, we therefore take the following proactive steps to SD-WAN migration.


1) SD-WAN Network & Services Design

  • Audit, Review, Design & Planning
  • Assisted to full designed deployments

The main key to SD-WAN migration is how you handle the SD-WAN network and services design process & procedures. Our focus is very much on how we design your target network properly in the first place. We start with your current network, audit and review what’s there and design your target network so it includes all the services and benefits you require.

2) SD-WAN Migration Capabilities Design

  • Logical step by step design approach to migration
  • Detailed custom migration documentation provided

Our next step is the SD-WAN Migration Capabilities Design – this is the design and everything else that’s involved to take you technically and practically from your current network to your target network. This isn’t something you can do in one day by the way; it might take 2 or 3 years! The reason for that is you need to factor in lots of interim designs steps. For example, your traditional legacy WAN network will more than likely need to be connected to your new SD-WAN network for a certain period, otherwise you’d have to move every single site to SD-WAN in one go, which probably won’t be feasible.

I should also point out at this stage that networks usually have lots of hidden issues that you accumulate over the years. They’ve always been there lurking, but somehow the network still works. We might uncover some of them during our audit, but don’t be surprised if, once you start making changes, further issues suddenly start manifesting themselves!

I’m sure you’d rather not be in a position where you don’t know what’s going on or why things aren’t working so, if you’re changing your network, you might as well clean things up at the same time by factoring all necessary changes into your new design.

To conclude this phase, we’ll define the interim designs, plan how they’re going to be implemented, put them through testing and document exactly how everything will be achieved step by step. The documentation can be extremely detailed or high level, depending on what you want to see.

3) SD-WAN Migration Execution

  • Full “white glove” services
  • On-site, remote and hands-off execution options

Then we move to SD-WAN migration execution, which is where the real transformation work begins. Because we’ll have planned everything meticulously by this point, if anything goes wrong, we can always roll back to the previous step. The more time spent in the planning phases, the faster the migration can happen! If you don’t plan properly, you may not be so lucky.

This is where we bring together our methodology, experience, knowledge of SD-WAN technologies and their vendors, and everything we’ve learned in working with you. I always say an SD-WAN migration is like one boat where we all row together. Essentially, if we want to be successful, you need to be successful and vice versa. Unfortunately, SD-WAN isn’t one of those projects where you get to sit back and watch what’s happening. But if you make the right time and planning investments and choose an experienced, reliable partner like Teneo, it should be relatively smooth sailing.


If you’re ready to get started today on your migration from a traditional legacy network to a next-generation SD-WAN network, I highly recommend we begin with our SD-WAN Workshop, delivered by our technical sales and engineering team – including me. You can find out what’s included in an SD-WAN Workshop on this page.

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