Blog · 26 Nov 2017

Disrupt or disrupted: How SD-WAN is changing the way we think about Wide Area Networks

Join Paul Taylor, as he delves into the world of Wide Area Networks and explores the importance of SD-WAN.

Senior Deal Architect, BT

Why SD-something?

Providing a mechanism for you to react quickly in your private and public networks to specific business needs (such as increased bandwidth on a big news day) is becoming more and more necessary — and expected. Today, applications rule and/or define the IT services estate. Software Defined WAN (SD-WAN) enables you to leverage hybrid network services to deliver greater performance, visibility of how your users interact with applications, as well as simplified control.

However, we must first overcome the common misconception that all SD-WAN offerings deliver the same capabilities, which is simply not the case.

Which SD-WAN offering is right for you?

The market has been pushing Software Defined Networking, which encompasses almost every possible iteration around: Software Defined Data Centres, Software Defined Architecture, SD-WAN, Software Defined Orchestration.

These are all great market definitions and align with the cloud adoption philosophy, which has contributed to making SD-WAN the next big thing in wide area networking. As a result, a large number of solutions are available, offered by many different players. Gartner expects the market to be worth $6.1 billion by 2020 with 30 per cent of enterprises having deployed an SD-WAN solution.

However, for all the conversations that are occurring, none answer the question 'Why SD-Something?’

All Software Defined technologies are driven by the view that they:

  1. are independent of a specific hardware platform
  2. have some form of automation
  3. are transport independent.

Understanding where a customer is looking within their end-to-end IT infrastructure drives different conversations. 

From a traditional network perspective, Software Defined Networking has been around for many years. For example, the ability to centrally control an endpoint device for an overlay capability is commonplace. Our own Connect Intelligence portfolio offerings have been successfully delivering these capabilities using technology partners such as Riverbed and Ipanema/Infovista.

Our partners are starting to evolve their products to deliver a full SD-WAN capability that encompasses secure connectivity between sites and performance path routing using the inherent WAN optimisation functionality they have honed over time.


What are the expected business benefits in the short, mid and longer term for your IT estate? What changes the status quo and investment in transforming your WAN services to an SD-WAN implementation?

 Let us first consider the components required to deliver an SD-WAN solution:

  • Centralised management — command and control of the edge devices.
  • Security wrap — wraps the controller to make it secure as it will be connected to the Internet.
  • Physical or virtual DC — host the brain and security wrap.
  • Edge devices.

All of these elements are specific to the deployment and are critical. No brain, no SD-WAN solution!

Add in the network elements, which could be a mix of public and private transport services, and you have all the capabilities to deliver an SD-WAN solution. 
Understanding these requirements, what features do you need to support your business? If you believe the market, it will be cheaper, faster and magically make everything work. Some of the other considerations include:

  • Which vendor is the right choice?
  • Which vendors support magic?
  • Which vendor can meet 60 per cent of my needs straight away?
  • Which vendors will still be around in three years and will I choose one of them?
  • Which vendors are the service providers betting on?

Cisco is betting on Viptela and so are a number of other service providers. Some have chosen Versa networks, others Nokia Nuage, while Riverbed — with its recent acquisitions of Ocedo and Xirrus — is starting to add more than one capability to the SD-WAN market. Meraki is also starting to move into the same space as the venture capital-funded vendors.

Market consolidation is key to the final shake-out of SD-WAN vendor choices. As bigger players make acquisitions, the choices are going to be based on features, functionality and price points. The fanboy approach for a particular vendor often clouds the technology choice.

When someone has decided they already like something, you can forget about the business requirement conversation. The technologist is chomping at the bit to say “I like 'X' so let's make 'X' fit”. That might work, but in reality, how do we support that, if we think about managed services? Cloud management is great, but if you don't have the skills or the resources to cover a 24/7 requirement, can operational teams step up to deploy and assure?

What are the business drivers behind your decision?

Understanding the business drivers for WAN transformation will help guide your decisions about which vendor to choose. And the absolute requirements versus those nice shiny requirements will evolve over time as technology advances. The when and how you start your path to SD-WAN is also heavily influenced by your choice of a hardware or virtual based approach. Choosing a solution and a partner that will allow you to input real requirements into the evolution of a solution is probably a sensible concept, but when you’re looking to quickly ‘save’ money, do the capabilities that may or may not come in the next 12 months matter?

It’s clear that SD-WAN has the potential to drive cost savings, but perhaps not to the extent that most organisations perceive, through the commoditisation of network transport services. The solution is one of trade-offs — although cheap transport is available, it may increase the risk to offer robust repair service level agreements. Reduction in complexity, ability to see application behaviours, performance routing and segmentation are a few of the key benefits — but are there tangible and quantifiable savings or improvements in service?

So when making a decision on SD-WAN, first ask yourself: why SD-WAN?