If you’re someone with an interest in business IT networks, it’s possible you might have heard mentions of Software Defined Networking as part of a Wide Area Network – or SD WAN, as it’s more commonly referred to.

However, the internet is rife with tweets, posts, and articles containing a concerning amount of misunderstandings with regards to what SD WAN really is, and how it can benefit your network. To that end, here’s a quick guide that explains the fundamentals of SD WAN:

Defining SD WAN

In order to fully understand what SD WAN is, firstly we need to address the ‘WAN’ part. A WAN is a series of numerous devices, all connected over an area. The internet can be thought of as a WAN. For businesses, a WAN is generally a hub located in the centre (holding main network infrastructure devices such as servers) which has several branches including cloud services, offices, and so on.

These locations each probably have a LAN (a local area network), which can become a WAN once it is connected to the internet and then other LANs on the network. Once this is completed, information and resources that are located at the hub can be shared all across the WAN, letting the other locations have access to the central systems including software, storage, and others.

What can SD WAN really do?

SD WAN does not get rid of anything already within your current WAN. Think of it as more of an add-on – a system, provided by software, which allows for more control over your WAN. You may see the term ‘SASE’ mentioned too – this is essentially rolling network security in with the concept of SD WAN.

Usually it’s only possible to get control over a device by syncing with it on-location, but the software which provides SD WAN is compatible with each device on the network, and replaces these controls.

But what does this really mean for a company, other than the fact that technicians working on the network will need to spend much less time moving around from location to location? We’ve collected a series of claims that tend to be made about SD WAN, and now we’ll check whether or not they’re really fact, or just fiction.

“SD WAN lets businesses quickly manage the priority of bandwidth and traffic”

It’s common for SD WAN providers to go on and on about how, unlike the more traditional methods of managing a WAN, their systems offer a much higher quality of service.

It seems though that this may verge on the side of false advertising. While it’s certainly true that with an SD WAN solution you will see improvements in the quality of your service, it’s not likely that SD WAN alone will make much of a difference. SD WAN is more of a tool to ensure you’re making the most out of what you’ve got – so the main changes need to be made to your hardware in order to maximise the efficiency of your networking structure.

“SD WAN lets businesses instantly expand to new sites”

For people whose work revolves around making sure remote locations are up and running online as quickly as possible, being able to instantly set up hardware would be a dream come true.

Unfortunately, as of now, it remains but a dream. As mentioned previously, SD WAN is not a replacement for good hardware. If you don’t already have hardware and connections in place, SD WAN has nothing to configure, and nothing to work with. It’s true, SD WAN can help get sites going, but it’s crucial that there’s already an existing connection – if there isn’t, you’ll still have to put up with long circuit installation times.

“SD WAN is a replacement for MPLS connections”

Many businesses – especially ones that need to have a lot of applications running over their sites – utilise MPLS connections, but these can be expensive. As such, many are wondering if SD WAN will function as a more cost-effective replacement.

MPLS stands for Multi-Protocol Label Switching, and is a technique used by high performance networks for carrying data. MPLS allows a business to dynamically alter the priority of data, and its route through the network. Critically important data can be given a high priority, and, you guessed it, less important data can be given a lower priority. Essentially it allows for the more crucial applications to run as quickly and efficiently as possible by monitoring the paths the data takes.

SD WAN actually can do something similar. Network traffic can be prioritised with the use of a managed CoS (Class of Service) system. Where it differs though is that whereas SD WAN is simply an overlay for your current infrastructure, MPLS is actually part of the infrastructure, and as a result, offers a lot more than simple tweaks to CoS.

So it’s unlikely that a software based service like SD WAN will, for now anyway, fully replace any actual hardware solutions. But in time it’s fully possible that we might see reliance on hardware solutions like MPLS get lower.

“SD WAN makes for a much better experience when using SaaS”

SD WAN can definitely be advantageous if, across your WAN, you’re making use of SaaS (Software as a Service) applications. This is due to the fact that you have your central hub which can make sure that all your satellite operations are able to access the same applications, with the data having the same speed and priority throughout.

Real-time applications simply must be working to their fullest potential, especially if they’re being used by customers or end-users. Having the ability to remotely respond to issues SaaS applications may have within your WAN means you don’t need to waste time getting someone there in person, which can save precious time. Keep in mind though, depending on which SaaS applications your company uses, and how crucial they are to keeping it operational, this may or may not impact you all that much.

Is SD WAN the right choice?

When it comes down to it, what may be extremely important to one business’ network may not matter at all to another’s, and as such, the points listed above may be of interest to you, or they may not matter at all.

To really work out whether SD WAN is right for you, have a think about how your network is being run. Do you work with a managed service provider who sorts out any issue the instant they pop up? Or do you have an in-house IT department who are stretched way too thin, having to waste crucial time travelling from site to site? If the latter is true, SD WAN might be the exact thing you need.