With over 68 million keyword results returned by Google, the term “SD-WAN” sure is a topic people are interested in learning about. As an independent subject matter expert in the networks and telecoms market it’s very much a topic which interests us too.

So, what is all the hype about, who is buying it, how are they sourcing it, what lessons were learnt during the delivery life-cycle, and most importantly does it deliver any benefit?

To address some of these questions TNC has produced this white paper - A buyer’s guide to SD-WAN. In it we will discuss the prerequisite activities required to validate SD-WAN as a suitable solution, explore the various approaches organisations consider when implementing SD-WAN, evaluate the vendor market, and provide some benefit analysis to give you an indication of what is achievable.

Validating the need for

SD-WAN marketeers have a lot to answer for when it comes to understanding the value of SD-WAN. Claims such as:

  • “Achieve 60% cost reduction!”
  • “Double your bandwidth””
  • “Remove expensive MPLS!”

are all common marketing strap-lines from many of the (mis)leading SD-WAN vendors and service providers. Unsurprisingly, these claims get the attention of CIOs and senior managers who often become enthused about SD-WAN without fully appreciating the level of change required. In reality of course, many of these claims are simply not achievable for most organisations.

To understand if SD-WAN is right for you, TNC always recommends developing a detailed business case to fully understand the level of change, both from a technology and operating model perspective. You should also clearly evaluate and validate the performance, commercial and operational benefits SD-WAN would deliver over and above a traditional WAN model. 

What benefits can my
organisation expect?

For organisations willing to compromise on access circuit quality and source their underlay through multiple local carriers, some level of cost saving is achievable. However, this approach introduces increased complexity in operational management and could impact consistent performance of the network.

The level of savings also largely depends on the existing baseline, the requirements defined, and the level of change required to implement the SD-WAN solution.

Although cost is a major consideration for most organisations, increasingly organisations are citing network performance improvement as the key reason to consider and ultimately adopt an SD-WAN solution.

With both the cost and performance points in mind, many organisations are aiming to balance the two to deliver a solution which improves performance, maybe through increased bandwidth or a different mix of MPLS and internet, for the same or slightly lower price, i.e. cost neutral. 

Sourcing Approaches

Based on recent buying behaviours of our customers, we typically see three sourcing approaches for SD-WAN:

Approach 1:
Do it Yourself

In this approach organisations tend to breakdown the sourcing of their networks into three elements:

  • Network Underlay – Typically this would be connectivity sourced on a regional or local basis using best-of-breed carriers
  • Network Overlay – An “off the shelf” enterprise SD-WAN solution, either appliance-based, or virtually deployed on uCPE
  • Network Management – In most cases, the network management function is in-sourced either as a central team or a globally distributed virtual team

A typical customer profile sourcing a DIY solution would have a highly dynamic environment which requires rapid site deployment and short-term connectivity requirements. If you are an organisation currently operating a single managed service provider, migration to a DIY approach would be a very sizeable undertaking with significant risks and challenges.

Approach 2:
Managed Service Provider / Telco

In this approach organisations would typically source all network services (underlay, overlay and management) through a single global provider, albeit some services may be sourced regionally or locally for cost reasons.

Unfortunately, the telcos have been slow to react to the changing market, and although now many offer a flavour of SD-WAN, antiquated contracts and traditional commercial solutions are impeding mass migration to this SD-WAN model.

Due to this, the take up of this approach has been limited, with only a handful of TNC’s customers taking this route to date. However, a recent survey of TNC customers indicated that this approach would be the most attractive to customers, specifically ones currently operating a single managed service provider network, because the transition, particularly from an operating model perspective, would be far simpler, and the end-state similar to the model they are comfortable with today.

Approach 3:
Network as a Service Provider

Over the last 18 months a new breed of service provider has emerged into the network and telecoms market claiming to offer “Network as a Service” (NetaaS). These providers, often referred to as software defined carriers or managed SD-WAN service providers, have effectively built their SD-WAN offerings from the ground up and sell the capability as a subscription-based network service, akin to that of the cloud compute model.

In this approach organisations would typically breakdown the sourcing of their networks into two elements:

  • Network Underlay – Typically this would be connectivity sourced on a regional or local basis using best-of-breed carriers
  • Network Overlay and Management – A proprietary (or in some cases a managed enterprise) SD-WAN solution, either appliance-based, or virtually deployed on uCPE, sourced through a single NetaaS provider. The network management function could also be provided through the NetaaS provider or be a mix of in and outsourced resources

Increasingly, service providers offering this approach are now also starting to offer connectivity (i.e. the network underlay) as part of the network as a service wrap, thus offering customers a single contract for all services. However, it is very early days for many of these providers, as such there are limited customer case studies available to comment on the successes and challenges opting for this approach would pose.

Do it Yourself Managed Service Provider / Telco Network as a Service Provider
Network Underlay Regional/Local circuit sourcing Global/regional circuit sourcing Global/regional circuit sourcing
Network Overlay “off the shelf” global solution Sourced through global MSP Sourced through global NetaaS provider
Network Management In-house management Sourced through global MSP Mix of in and outsourced resources
Which SD-WAN Vendor
should I choose?

After validating the need for SD-WAN, the next logical step is to select a suitable infrastructure/software vendor to deliver the SD-WAN functionality you require. There is a general misconception that SD-WAN is a product as opposed to a conceptual design made up of various components, and that all vendors using SD-WAN in their solution marketing offer the same or similar set of capabilities. This is not really the case.

Many vendors in the SD-WAN market have primarily redeveloped and relaunched their traditional solutions, such as WAN optimisation, routing and packet pushing, and security solutions, and brand this amalgam as SD-WAN.

Alongside these traditional vendors is a new breed of pure play SD-WAN vendors. These vendors tend to be very strong on the core features and functionality of SD-WAN, but less so on complementary features around security and optimisation.

Perhaps not surprising given these two types of vendors start from very different places and have developed their solutions very differently, the core features and functionality of their solutions can also differ markedly.

Couple these vendor options with the three sourcing approaches detailed and you are left with lots of possible sourcing combinations. To help navigate the complexity of the market, TNC always recommends customers develop a detailed statement of requirement which captures key business, solution, service and commercial requirements and defines a clear and concise evaluation criterion against which providers and sourcing approaches will be measured.  


Striking the right balance to deliver optimum benefit for your organisation requires detailed planning, preparation, and importantly time to ensure the right decisions are made and benefits can be recognised, measured and reported upon.

To help customers with the strategic planning and preparation for SD-WAN, TNC has developed a strategy development framework to assist customers at each step of the sourcing lifecycle; business case creation, statement of requirement development, option analysis and sourcing strategy.

If you would like to find out more about how we can help you on your SD-WAN journey, we would be delighted to talk to you and share our experience and knowledge.

TNC delivers over 100 major programmes per year


Other than matters relating to The Network Collective, this research is based on current public information that we consider reliable. Opinions expressed may change without notice and may differ from views set out in other documents created by The Network Collective. The above information is provided for informational purposes only and without any obligation, whether contractual or otherwise. No warranty or representation is made as to the correctness, completeness and accuracy of the information given or the assessments made.

This research does not constitute a personal recommendation or take into account the particular investment objectives, financial situations, or needs of individual clients. Clients should consider whether any advice or recommendation in this research is suitable for their particular circumstances and, if appropriate, seek professional advice.

No part of this material may be (i) copied, photocopied or duplicated in any form by any means or (ii) redistributed without the prior written consent of The Network Collective Limited © 2022

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