Why use SD-WAN?

Why use SD-WAN?

SD-WAN has been cropping up in a lot of recent customer conversations, but it’s not for everyone, so I wanted to discuss the key use cases.

This may change over time, but right now I see five reasons for looking at SD-WAN: resolving network performance issues, improving application performance, optimising voice and video conferencing, quickly connecting new sites, and reducing networking costs. Clearly, if more than one of these requirements apply the justification becomes even stronger.

For those unfamiliar with the subject, my SD-WAN made simple post will help, but by way of reminder SD-WAN is short for ‘software-defined wide area network’. It applies software-defined networking (SDN) principles to WAN connections to remote sites, such as those linking branches to a data centre, and so is either a substitute for or supplement to existing MPLS connections.

Solving network performance and reliability issues
Many multi-site organisations use MPLS to connect their branches to their data centre and/or head office. In theory, these ‘dedicated’ links should provide reliable connectivity, but many organisations struggle with poor network performance.

In practice, you may well be sharing your MPLS resources with other businesses, which degrades the service. This means that staff at branches suffer from dropouts, jitter and poor application performance. Worse, they may just put up with it and not tell the IT team – so you may not know quite how bad things are.

With SD-WAN you can easily use existing dedicated internet links, and even inexpensive broadband connections, to build an application-aware private network that overcomes these performance and visibility issues.

Whatever transport protocol you have available can be used by SD-WAN, such as 3G, 4G LTE, MPLS, Internet or Wi-Fi. This aggregation of links increases flexibility and resilience, as you can re-route traffic if required when one link goes down.

Security is also improved. Unlike traditional WAN solutions, which handle security through multiple appliances at each branch office, SD-WAN can include security functions like a stateful firewall and IPSec in-box and at a lower cost. This means, for example, you could integrate SD-WAN with a cloud web content filtering service and offer malware defences for every branch.

Improving application performance
Wherever applications are served remotely, the network quality of service (QoS) becomes important. Traditionally, this would have been application and desktop virtualisation solutions, such as Citrix XenApp and XenDesktop, but now it’s increasingly Office 365, ERP, finance and line of business applications delivered from the cloud.

One of the most important advantages of SD-WAN is that it can provide secure intelligent path control that chooses the route taken by traffic, based on application. This secure traffic-forwarding capability is set at the centralised controller level and then pushed out to all SD-WAN devices. Policies can be based on IP addresses, application profiles, port number, quality-of-service markings, time of day, or any other number of variables.

A traditional networking topology is based on linking everything directly back to the centre (backhauling). But if you’re making increasing use of cloud, like most businesses, it makes less and less sense to do this, if much of the network traffic is then going to the cloud.

By using SD-WAN, you’ll be able to route relevant traffic directly from each site to the cloud, which will help optimise the efficiency of your network, and thus further improve application performance for cloud solutions. Your users will get faster application performance, printing, streaming and downloads – all improving their experience, and boosting productivity.

Video and voice
If like many SMEs, you use real-time voice and video conferencing services like Skype, you’re probably running your voice and video over commodity broadband connections, with no QoS features in place.

While this probably works adequately most of the time, you’ll almost certainly have many instances where quality is unacceptable, or calls are dropped. With SD-WAN, you can prioritise voice and video traffic, both inbound and outbound, to overcome these problems and improve the user experience.

With SD-WAN, you can also use multi-path technologies to route traffic along more than one link, which makes it easier to get around problems with a carrier backbone. If one of your links dies, your call is re-routed, and you probably wouldn’t even notice.

Setting up new sites quickly and easily
Getting a new MPLS connection ordered and provisioned might take months. In contrast, SD-WAN can use readily available alternatives, such as a standard broadband internet connection, to be operational in just a few days.

If you’re also dealing with rapid growth, lack of standardisation becomes an issue as sites are configured by different people in your IT team. With SD-WAN, features like Zero Touch provisioning and Configuration Profiles help to make sure that all sites are configured identically, as well as saving time.

This also helps greatly for change management, as a configuration update in one place can be applied to all sites. Overall, SD-WAN networks are easier and simpler to manage than the branch routers of existing networks.

SD-WAN solutions will give you highly detailed centralised reporting, and a high degree of application and network visibility, which makes it easy to see exactly what is happening at your remote sites. Many SD-WAN solutions also have built-in tools that help with remote diagnostics, such as the ability to perform packet captures and see the network state.

Reducing networking costs
MPLS can be expensive, whereas SD-WAN uses commodity connectivity and can drive your networking costs down. Using SD-WAN can enable you to get the same kind of enterprise-class results from affordable broadband links that would previously have needed top-end MPLS connections.

You might find your incumbent network provider discounts its MPLS offering to match the cost of SD-WAN. Even in this scenario, the other benefits of SD-WAN are usually enough to make it a compelling alternative – saving money can be just a bonus.

Managed service
For many organisations, SD-WAN provides an ideal mix of manageability, reliability, performance and security, while reducing costs compared to a traditional wide area network.

In many cases, the migration to SD-WAN can be handled gradually and carefully, simply replacing existing links as their contracts expire and running a hybrid system until everything has moved to SD-WAN.

Having said that, any shift to a new technology needs to be done properly. Taking SD-WAN as a fully managed service, rather than handling it on your own, can help ensure that you take maximum advantage of all the benefits from day one.

If you'd like to look into whether SD-WAN might help you organisation our SD-WAN Strategic Workshop and Assessment might be of help. Alternatively, feel free to get in touch with me via our contact us form.