SD-WAN: wrong timing, wrong technology

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We know from IDC that 80 per cent of enterprises will have implemented SD-WAN at some of their sites by 2020, and there’s a widespread understanding that a more flexible network infrastructure is needed to support a digital business. What’s less clear is how to get there.

At BT, we come across a lot of organisations who have set off on the journey with the wrong roadmap. They have some idea of the destination but they don’t understand the important stops they need to make along the way.

SD-WAN demands an application-centric approach to network infrastructure.

Therefore, a detailed understanding of your application environment is fundamental for a successful transition to SD-WAN and cloud-oriented services. Knowing what you currently use (bandwidth consumption by application or site), quality of service (QoS) and performance data will inform the bandwidth you need in the future, which in turn helps makes the business case for SD-WAN.

When you have a clear understanding of how your business critical applications function you can start to map hybrid technologies to network transport, including traditional MPLS and other types of connectivity that align with customer premises equipment and supporting VNFs (Virtualised Network Functions).

The next big challenge is to moving from proof-of-concept to full-scale deployment.

There are three common pitfalls to avoid


1.      Wrong technology at the wrong time

Make the wrong choices at the wrong time and you’ll be stuck with technology that’s not ready for the demands of operational deployment. Or worse, you’ll find yourself going down a technology dead end. Increasing the likelihood of this happening is internal conflict between IT and network teams who use multiple legacy tools.

Don’t let legacy determine your future. The technology and the vendors that supplied it can trap you into a way of doing things and you’ll end up trying to bolt  a little bit of the future onto the past. The CIO likes the idea because it sounds cheap; the IT team are on-board because it’s familiar; and your legacy vendors love it because it means you’ll continue to spend money with them.

You have to consolidate and optimise your existing IT as part of a transition process to SD-WAN. MPLS still has a huge role to play, but for SD-WAN to work as the cherry on top, you’ll need to develop a unified platform with gateways that can share information in a usable way.

2.      Wrong security

Future infrastructure will involve greater complexity. Working with providers who can’t manage both overlay and underlay introduces a greater chance of service failures and security issues, along with frantic finger-pointing as you try to resolve issues that arise.

Adding local internet breakouts to an MPLS-based network moves the secure edge of the network from a small number of central locations to a large number of dispersed locations, increasing your risk exposure. This is why network and security can no longer be considered separate entities.

Firewalls, identity or access management and intrusion detection and prevention need to be embedded directly into the network. Policies must be set up that classify sites to determine appropriate security postures across applications and sites.

3.      Wrong costs

Both of the above risk hidden costs that can derail SD-WAN projects or take them wildly over budget. The worst-case scenario with the wrong technology is that you’ll have to start over again. Security can also be a money-pit unless you plan properly and revisit your policies.

The other potential mistake is to hang the whole project on the promise of cost savings. Better to think of SD-WAN as a way to optimise the bandwidth you’re using without spending a fortune, delivering a more cost-efficient network that’s fit for the future. This model involves defining what kind and size of underlay meets the needs of the business in each location, and coming up with a shopping-list of technology solutions to best deliver against the business requirements at scale.

When you consider the possible pitfalls and the speed of change around SD-WAN, it makes a compelling case for finding a third party to partner with you on the journey. In the next blog we’ll look at what you should look for in a provider and what BT uniquely brings to an SD rollout.

Check out our related reading:

1.      Ovum report, 2019 Trends to Watch: Network Services

Discover what network trends to look out for in 2019 with Ovum’s latest report covering SD-WAN, NFV, hybrid networking and cloud connectivity services.

2.      The CISO & CIO’s guide to securing networks in the digital age

Here, we outline how security will become a key component of your future network strategy.


Steve Coakley


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