Whether its UK, European, or global in scope everyone needs SD-WAN for their network, right? 

That’s the view of many in the networking industry, and is certainly the view of every service provider and vendor. 

But is it actually true?  Does everyone need SD-WAN for their network, particularly if the network is entirely within the UK?  The reality is a lot more complex, and a lot more nuanced, and quite possibly the answer is no – not everyone needs SD-WAN, especially if it’s a UK-only network. 

In this article we will explore why we often find our customers, and ourselves, reaching that potentially surprising conclusion – so read on! 

Of course, the best place to start is understanding why SD-WAN arose in the first place.  There were two main drivers that started the trend for SD-WAN adoption: 

1. As organisations started to move workloads from on-prem data centres into the cloud, more traffic needed to traverse the internet to reach these applications.  Some organisations started to find that their private, typically MPLS networks were becoming less efficient at routing and delivering this traffic, and a view developed that internet connectivity would improve performance
2. In some cases, migrating from MPLS to internet connectivity enabled cost reductions on access circuits, which led to a view that networks based on SD-WAN were fundamentally cheaper than MPLS 

 In other words, the view began to crystallise that networks based on SD-WAN performed better than MPLS networks, and were cheaper.  Great, right?  What’s not to like about a new technology that is better AND cheaper? 

 However, the issue is that these statements aren’t always true – there are many cases where networks based on SD-WAN won’t perform better than MPLS, and there are even more cases where they also aren’t cheaper.  Nowhere are these two challenges more clear than when we look at purely UK networks, and here’s why. 

Firstly, let’s look at performance.  The basic logic is that a network using internet-based connectivity managed by an SD-WAN overlay enables traffic to get to where it wants to go, typically somewhere in the cloud, quicker than being backhauled to a data centre, and out and back through an internet gateway.  The problem with this view is that it doesn’t often describe the reality of UK-based networks.  In reality, an “internet” connection in the UK is really a private backhaul from your premise to your service provider’s nearest POP, then a private route across their network, to their internet breakout, which is almost certainly in London or Manchester, and then out to the internet and back.  In other words, the exact transit that internet connectivity is supposed to avoid is exactly what is happening, just within the black box of a service provider’s network. 

Furthermore, whilst SD-WAN does offer features that MPLS doesn’t, the complexity of SD-WAN is often overlooked.  In practice, SD-WAN is significantly more complex to design and manage than MPLS, which can often lead to either cost and time overruns in procurement and deployment of SD-WAN solutions, and very often to significant performance issues in-life, to the extent that a not-insignificant percentage of SD-WAN solutions fail and the organisation has to roll back to MPLS. 

Finally, we have to address the issue of cost.  Let’s be completely clear – unless you are prepared to downgrade your access circuits, networks based on internet connectivity with SD-WAN overlay in the UK are NOT cheaper than MPLS networks, and are often more expensive. 

The reasons why are clear – as noted above, given that the underlying network is virtually identical whether MPLS or internet, it shouldn’t be a surprise to know that the price of internet connectivity and MPLS connectivity in the UK for a given bandwidth and access technology is almost identical.  So, little or no cost savings on the access.  And the bigger point is that SD-WAN hardware and software, and the professional services required to design, deploy, and manage them are often more expensive than MPLS. 

To summarise therefore, it definitely isn’t a given that a network based on internet connectivity with SD-WAN overlay will perform better than an MPLS network in the UK, nor that it will be cheaper. 

However, that’s not to say that there aren’t good reasons why SD-WAN may be the right choice for your UK network.  SD-WAN definitely offers a number of benefits such as: 

• Ability to deploy active-active configurations enabling full use of all available bandwidth 

• Increased visibility and control of network and application performance   

• Simplified orchestration of network management and policy configuration  

 Also, for organisations with most workloads either in or moving to the cloud, it is certainly a strong option. 

It is important however to assess whether those benefits offset the addition costs and complexities that SD-WAN brings.  The truth is that many organisations that still have a lot of on-prem workloads still find that MPLS delivers the performance they require, is simpler to design, procure, deploy, and manage, is often cheaper, and definitely doesn’t require a major transformation programme. 

Given the picture set out above, TNC’s view is clear – SD-WAN is an application that, like all applications, delivers some benefits and carries some costs.  For some organisations, the benefits will outweigh the costs and SD-WAN will be a great choice.  However, for many other organisations, the benefits are less clear and the costs greater, and these organisations need to be careful not to get swept along by over-enthusiastic service providers and vendors, for whom SD-WAN is always the right answer, and end up procuring solutions that will deliver more issues and benefits, leading to many years of frustration. 

How can TNC help?

Given the criticality of designing, procuring, and deploying the best-fit network to deliver the performance your organisations requires, and the challenges of navigating a hugely complex and fast-changing market, making the right choices for your future network is more difficult than ever.  There are more solutions, options, and service providers in the market now than ever before, meaning there are more opportunities to deliver something great, but also more opportunities for things to go drastically wrong. 

 To help leading UK and multinational organisations develop and execute industry-leading strategies for their new networks, TNC has developed a comprehensive tool kit to support you right through your journey, from developing the technology strategy and building the business case, to supporting your supplier selection process, assuring your solution deployment, and helping you optimise the solution throughout the lifecycle. 

If you would like to find out more about how we can help you, we would be delighted to talk to you and share our experience and knowledge. 

TNC holds over 4.3m active market data points covering WAN, data networks, fixed voice and mobility

More

Insight, blogs and white papers