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The ultimate guide to SD-WAN – 5 main factors to consider

John McVicker

SD-WANs are all in vogue for the technology professional. Everyone is talking about deploying them, managing them and using them as a core platform to scale their existing business. 

However, SD-WANs aren’t for everyone. Not every organisation can really justify putting one in, and incurring the upheaval of network, application and general digital transformation. Here we look at the five critical factors that every organisation needs to consider to embrace this latest-generation network technology.


1. Do we actually need an SD-WAN and is it right for our organisation?

Not every organisation will be an ideal fit for SD-WAN technologies. As part of the evaluation process, it is worth considering a range of factors related to applications, users and general performance requirements. 

Suppose the business operates with cloud-based applications at its core, e.g. Salesforce. In that case, it will likely benefit from SD-WAN solutions that enable traffic to be directly routed from the branch straight to the cloud via public internet links. 

Conversely, if the business does not predominantly use these apps, an SD-WAN may not be needed. Or may not deliver the benefits it could if the business operated differently.

In a post-Covid world where remote working and flexible working practices are increasingly the accepted norm, it is worth considering whether remote users have bandwidth or application performance issues that could be alleviated by an SD-WAN solution that would enable policy-based traffic management. 

Fundamentally, SD-WAN technologies enable new branch locations, new applications and new users to be added swiftly and efficiently. 

Some businesses are understandably not looking to grow or change much in the current economic environment. With a technology centred on facilitating network and application change for users, deployment of SD-WAN may be an unnecessary change where the status quo if more than acceptable.

2. Can we afford it, and is it worth it?

There is no doubt that the headline business case in support of the deployment of SD-WAN technologies, provides direct or hard cost savings and less tangible or soft cost savings.

The hard cost savings will come from cost reduction to manage the network, reducing the number of network links required (and likely sizing of those links) as well as a potential decrease in cost and technology of those links. 

For example, a site that could have been connected with a dark fibre might now be served by mobile or multiple broadband connections, and represent an overall reduction in cost.

The soft cost savings will be derived from the ease of bringing on additional operational sites. Or users and improved application performance which will have a positive impact on staff productivity and costs. 

However, to achieve these cost benefits and derive many of the performance and management benefits of deploying an SD-WAN, the organisation must undertake the project.

With a clear business case of upside, it will primarily come down to the affordability of upfront costs, the costs associated with changing or modifying network infrastructure, and the costs to support and manage the service after it has gone live. 

While it might be evident that the business case for SD-WAN will deliver an ROI in say 18 months, you first have to invest. 

3. Selecting the right Channel Partner and Vendor that meets our needs

Vendor and Partner selection are some for the most problematic areas to navigate, having decided to deploy an SD-WAN. 

With so many vendors to choose from (at last count more than 70 vendors in various parts of the globe), and so many partners to deliver the solution, the array of decisions and choices of the commercial model to embrace can be, at times, overwhelming.

Key considerations when looking to select the correct Vendor and Partner will include:

  • How will the solution integrate security considerations – in the core, at the edge, a hybrid approach? Does the Partner understand and can help plan the best strategy?

  • Does my proposed selection enable the use of lower-grade WAN transport solutions like consumer-grade broadband connections or even mobile connectivity, without degrading application performance or delivering a reduced SLA overall?

  • Does the proposed solution simplify the network edge, into a single unified platform that makes it easy to manage and orchestrate network or application changes in a simplified management framework?

  • Does the proposed solution, and service provider, provide real-time visibility and analytics into what is happening across the SD-WAN, to make it super easy to fix any problems?

  • Does the Vendor or Partner, have a strong base of complementary technology vendor relationships, and a depth of skill in those different vendor technologies makes it easier to integrate the chosen solution with other core service elements?

  • Does the Vendor or Partner have a service support capability that matches my business need, i.e. Enterprise-grade, and has a robust solution for remote, on-site support, sparing and general maintenance?

  • Are the prospective Partners able to provide live references to demonstrate where they have done this before?

  • Does the overall solution provide better value-for-money than my existing infrastructure solution and simplify how the network and applications are managed?

The considerations above are pretty important ones to resolve; they are by no means the sole considerations when considering the vendor technology and Partner to bring the service to life. They deliver on many of the promises that SD-WAN technologies look to provide. 

Other elements to consider will include speed and ease of deployment and service migration, in addition to some roadmap to enable future-planning of applications, users and general expansion to drive a depth of use of the SD-WAN that is deployed.

4. Deploying and managing the SD-WAN service

Having chosen and technology Vendor and a Partner to provide the service, it is essential to consider how the service will be deployed and how it will be managed once it goes live.

The deployment of the service will almost certainly be one that is ultimately debated very early on in the life of the project, as this is critical to ensure that any new transport infrastructure is ordered correctly. 

The old service decommissioned appropriately, and any migration of applications can occur (even if their migration is temporary but enables the business to continue operating whilst this network is changed).

Additionally, it will be necessary to consider the sheer logistics of delivering equipment to different business locations, ensuring it has been configured correctly.

It has been received as planned (by usually confirming with somebody that it is there) and then ensuring that the Partner has scheduled a qualified engineer to do the deployment as planned when planned. 

Ensuring a focus on providing that the service is deployed in a single visit – planned, executed, installed, live.

Once the service elements have been delivered and received on-site, there needs to be a carefully coordinated plan around all aspects of change management. 

  • How will it operate at the site? 

  • What will it mean for the business both centrally and in each location?

  • How applications will now operate, what it will enable for staff in each place? (or those working at home or in even more remote areas).

All of these elements around logistics, maintaining service, change management, ordering of equipment and service elements, will all need to be coordinated by an experienced and knowledgeable Project Manager. This professional can make the SD-WAN service work well for the organisation from the outset. 

Conversely, if they fail to schedule and manage the project adequately, this can cause some of the benefits of this new technology to be diminished.

5. Planning for further change

With the service now alive, users accessing applications across this service, and the new transport network in place, it is appropriate to plan for further change. This change can manifest itself in many different forms, but an SD-WAN service will be subject to change almost from Day 1 of its life.

As the business evolves and grows, it will likely add new locations – either office locations or staff working remotely – it will see staff join and leave and add or retire applications to support the business in operating more efficiently.

With this inherent change at the core of the architecture and business operation, it is essential to have a plan, coupled with comprehensive policies and procedures that can accommodate new locations, new staff, changes in applications.

All against the backdrop of a benchmark of what “good” looks like – how quickly does the SD-WAN infrastructure need to be able to add a new site or staff member? 

What is an acceptable performance for an application type across the network? How are new security policies deployed in response to new and emerging security threats?

It is clear that in addition to the five significant considerations contained in this discussion document, many other smaller sub-considerations have a direct impact on the bigger picture. 

Additionally, there is no doubt that if an organisation can make a business case work for the deployment of SD-WAN technologies, there are many benefits to be derived from that service. 

For these benefits to be realised, this new service must be carefully planned, migrated and managed.