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How to Successfully Migrate an SD-WAN

John McVicker

“Good, bad or indifferent, if you are not investing in new technology, you are going to be left behind”. -- Philip Green

This quote from the retail entrepreneur, Philip Green, clearly illustrates the challenge faced by many organisations worldwide. They look at how they can invest in innovation to support their new and evolving operational models, following the Pandemic of 2020. 

At the heart of many conversations within IT departments across the globe, it focuses on finding ways in which the organisation can optimise its network to cater to an increasingly dispersed workforce, an array of cloud-based applications, and different access technologies, whilst providing maximum control and visibility to performance. Naturally, the notion of SD-WAN is front and centre for many.

However, it is unlikely that any organisation will be deploying an SD-WAN without already having some form of network infrastructure already in place. With that existing infrastructure already deployed, migrating to the SD-WAN – keeping the business operational and continuing to enable users’ access to applications and services that make them productive – is most critical.

Migrating between that legacy infrastructure to an SD-WAN requires some planning and consideration of several vital factors. 


1. Know what you have and what you want to keep

Before starting this complicated project, it makes sense to take stock and compile a complete inventory of everything included and operating alongside the new network service. 

Services running across the network, applications deployed and accessed at each location, user numbers at each site, IP address schemes that need to be catered for, details of security policies and infrastructure that underpin operations. 

Collating a comprehensive inventory of these application and network assets will enable you to take stock of what you have, make decisions about what you no longer need, and rationalise the service. It will ensure that the network is deployed to enable each site and application to operate optimally. It will also allow the control of costs and performance for this new service – like moving house and discarding items that no longer suit your style or needs!


2. Agree on the network design and operation

Migrating users, applications and services across to a new network architecture is complicated. And if you are looking to truly maximise the benefits of SD-WAN, then taking the same design as the organisation already has, and then virtualising it, you will miss many of the benefits that this new technology promises. 

Key considerations will centre of access technologies, application performance, users per location, rate of change of the business – is it growing the number of applications it is using as part of digitisation or automation? – and general growth or decline in the number of sites that the business operates. Additionally, this general network and service design will present different operational considerations for the existing support infrastructure – either the in-house technical team or the external partner provider. 

Making sure how the service will operate and behave is critical the upfront decision. Equally important is to focus on the in-life management, support and operation of the service – how many people will be needed to support the organisation, the support and service desk processes to support users, and how will issues be resolved with modified procedures. 


3. Agree on process and timeframe for cut-over to the new SD-WAN

Once you have a clear understanding of your network, access, application and support infrastructure, it makes sense to have a straightforward process for migrating sites and applications onto this new service. This migration will need to follow a clear and structured approach and must be carefully managed to ensure that things happen methodically, safely and predictably. 

Typically this is a process that is lead and managed by a qualified Project Manager who will provide structure to the migration process. This structure will ensure that access lines have been ordered and are available at each of the business sites. 

Ensuring users are made aware of any change management. Often this critical step is overlooked. 

Any on-site equipment has scheduled for configuration and delivery and a plan to maintain the two network infrastructures alongside each other until the complete migration has occurred. 


3. Make sure the equipment is staged, configured and ready for professional deployment

An integral part of the whole process of migration, the programmatic and predictable staging and configuration of the new equipment will ensure that the service is deployed and has minimal variances. Some sites will require different equipment on-site compared to some smaller sites where there may be limited equipment, but this all needs to be carefully staged, configured and deployed to ensure that everything operated as per the plan and schedule set out in the stage prior. 


4. Organisational alignment

New technologies like SD-WAN deliver different (and hopefully more) benefits to an organisation regarding cost reduction, productivity, application performance, support and overall control. And yet, to maximise the benefits that this technology promises to deliver, there needs to be a transparent organisational alignment process or change management.

A complex and very detailed function, the essential elements here focus on keeping staff and external partners, aware of the changes, the benefits that they will deliver, and giving them insight into this change and the general improvement that it will provide. 

A change in the underlying infrastructure may present some operational challenges when initially deployed. Having staff and partners involved in the process will ensure that there are no surprises and even encourage the team to help resolve those issues rather than magnify them a lack of knowledge. 


5. Deploy the initial “early adopter” sites

With the plan delivered, the team across the changes coming and the access network and hardware ready for deployment is time to start to deploy the “early adopter” sites and begin the process of cutting over from the old service to the SD-WAN infrastructure. 

The deployments to these initial sites will likely present some operational, logistical and project management issues. Still, this learning will help make the wider roll-out smoother and easier to control. It is essential to assess each of these initial deployments to identify areas of improvement, operational issues that might be significant for larger sites or across many different locations, and plan accordingly.  

It may also inform a fundamental change to the overall project plan and service architecture if it becomes apparent that the deployment is more complex and will take longer than initially anticipated, and that is a good thing. 

It is better to know that now than later, during a full-scale deployment when issues are magnified, and the pain of fixing them is much higher, it takes longer and costs the business valuable lost productivity. 


6. Test, Refine, & Go

With a plan that has now stood the first deployment test and likely undergone some modification, it is now time to roll-out widely to deploy the full solution. 

As with the single sites, the deployment of multiple locations requires a coordinated approach to ensure that access lines are “alive” as planned. 

That equipment is available (if needed), technicians scheduled to turn on the service and ensure it is operating as intended, and the team ready to start to use it.

When you have deployed several sites, in different locations and with varying numbers of users or applications, it is sensible to assess and “correct course” as you go. – perhaps the network needs to be dimensioned differently? Maybe the configuration of the equipment needs to be modified? Perhaps technicians need to be scheduled to be on-site for longer than anticipated.


7. Turn off the old service

With the new service now alive and operating as planned (and this can take between a week and up to a year for very complex deployments) it is now time to turn off the old service. The decommissioning of this old service will likely require cancellation of existing network infrastructure (making sure not to cancel newly deployed infrastructure), the uninstallation of old equipment and migration of any remaining applications or users onto the new service. 


8. Monitor, Manage and Maintain

Think of this new infrastructure as a living and breathing organism. You realise that it requires constant monitoring and maintenance to deliver the benefits it promises, for the organisation. It is the process of persistent review, correction and optimisation, with vigilance to make changes and modify access, that will enable this migration to be considered successful and genuinely delivering the benefits to the business.

It is easy to see that the process of migration can be one that has several areas to be careful of. One that shows that this migration need not be too daunting, as long as there are diligent planning, execution and monitoring to ensure that the service delivers as planned.