It Takes WAN to Know SD-WAN

Director of Product Richard Beeston breaks down the ‘whats’ and the ‘hows’ of SD-WAN.

There are already lots of different ways of connecting your business locations to each other by connecting them to the Internet. Many customers even have multiple connections per site. This has often been a necessary evil to enable business services but it can add additional cost and complexity to a company’s connectivity estate. Organisations have invested lots of time and resources into setting up MPLS networks to allow secure, predictable levels of connectivity between locations.

These technologies have been tried and tested over many years. For the last few years, the phrase ‘SD-WAN’ has been about and a number of vendors and service providers are offering SD-WAN services. However, it’s not always clear what SD-WAN is and why it could be important to a business.


Let’s define what it is and then we can look at some basic examples of how it might be used. SD-WAN stands for Software-Defined Wide Area Networking. Great! But what does that mean?

Firstly, wide area networking (WAN) can simply be thought of as the way our different offices and locations all communicate; be that over a standard Internet connection like the ones we have in our homes or the complex MPLS ones that support our industries and services. These are usually set up in advance and sometimes carry quality of services metrics to ensure services like voice or video work consistently. However, they can be difficult to change, especially in a dynamic way, on a regular basis.

That’s where the software-defined (SD) bit comes in. This element lets SD-WAN users and providers easily configure things like policies, WAN link selection and security profiles, not only at the network level or user level but right down to the application level. The services often combine multiple underlying WAN technologies to provide the service. For instance, you may have an SD-WAN device that is connected to both a company’s MPLS network and the Internet via independent links. But, again why?


A company has an established MPLS network that links all branch offices back to HQ. At HQ the company has a large costly connection back to the Internet. In the company’s MPLS network all traffic, be that from HQ or a branch, is routed back to HQ and if it needs to go to the Internet then it’s sent out over this single link.

The company has recently moved many of its software applications into private and public cloud services. This has resulted in much more traffic needing to go out over the Internet link. This has placed an additional burden on the link and made the network inefficient. The company may need to invest in upgrading its single connection. Or they could look at deploying lower cost “local” Internet connections in each branch.

SD-WAN can help here. By enabling intelligent path control and application optimisation with the implementation of a local Internet connection for each site, the company can push traffic out to the Internet in a more efficient way, while still maintaining control and security of the traffic. Quality of service metrics can be applied to the traffic as well to make sure users always get good service and that the network is running in an efficient way again. With having multiple connections the company also has resilience built in. If one branch’s Internet connection goes down the others will still work and the failed branch’s Internet requirements can be routed back over the MPLS network.

SD-WAN will allow the company to apply specific metrics, policies and routes to their applications. For example, after running the service for a while they were able to determine through the reporting capabilities that the finance application required more bandwidth at month-end. The IT team set up a policy to reflect this in the network. Finance users now have access to more network resources at critical times to make sure their critical applications work when they need them to.

In summary, SD-WAN is capable of many things. Some of them relate to cost optimisation on connectivity, others relate to efficient use of WAN links, while others still make sure a company’s applications and services are running as well as they can be. The Software used for the SD-WAN sits on top of all the devices, meaning changes can be easily pushed to the devices from a management centre rather than having to access each router individually. This in itself has many benefits. It makes changes to the WAN more efficient and dynamic, it reduces error and it allows for reporting on the WAN links to ensure they are always used correctly and secured appropriately.

Daisy and Cisco SD-WAN

Daisy works with Cisco to provide SD-WAN services. We can provide this as a fully managed service or as a shared service with your IT team. We’d love to speak to you about how we can help you make the most out of your existing WAN links and use SD-WAN to empower your business and users.

This article was written by Richard Beeston, Director of Product at Daisy Corporate Services.

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