IoT Glossary

What is SD-WAN?

A software-defined wide area network is a method of architecture that creates a virtualised network overlay connected to a central one.

What is SD-WAN?

SD-WAN (software-defined wide area network) describes a method of wide-area networking (WAN) that creates a virtualised network overlay spanning multiple locations, connecting them to a central network. Compared to traditional networking architectures, SD-WAN makes it easier for businesses to manage all connected devices from a single location. It can simplify traffic management on large IoT projects, reduce outages and enhance network security.

Discover more about SD-WAN technology and how it can support an IoT strategy as it scales up.

What is SD-WAN?

SD-WAN is a collection of local area networks (LANs) that communicate with each other over a large geographical area (anything between a few miles to thousands of miles) or over multiple sites.

An SD-WAN is software-defined, meaning that it is programmatically configured to follow operational rules defined by the business that owns the WAN.

An SD-WAN operates on the basis of several key principles:

Multi-connection support

Business network infrastructure often consists of multiple connections and transport methods, such as a combination of 4G LTE, 5G, broadband and Wi-Fi. An SD-WAN solution can effectively sit on top of all of these connections for simplified network management.

Dynamic path selection

SD-WAN can automatically route data traffic to the most appropriate WAN link, depending on traffic characteristics and network conditions. So if one link is in danger of overload, traffic can be sent down another path to maintain overall performance levels.

Policy-based management

To ensure reliable performance, businesses may want to give transmission priority to particular services: video calls for customer service, for instance. SD-WAN technology allows businesses to operate quality-of-service policies, whereby categories of traffic can be automatically steered to particular paths according to business preferences.


Historically, multiprotocol label switching (MPLS) has been the most popular method for a wide area networking. MPLS is essentially a private connection linking branch office locations to a central hub. It is regarded as a reliable and secure method of network management.

While this system is often a good option for linking branch offices to a business headquarters, it was not designed to handle the volume and dynamic nature of data traffic that can result from having large numbers of IoT devices or IT user mobility. This can cause strain or variability on data bandwidth which leads to a drop in performance quality and poor user experience. It can also be expensive to upgrade an existing MPLS solution to accommodate new IoT initiatives.

By contrast, SD-WAN provides an easier way to manage large volumes of devices and multiple types of connection and automatically route traffic to the most appropriate path. For businesses seeking to scale up their IoT strategies, SD-WAN is often a more flexible and cost-effective option.


Traditional networks rely on dedicated hardware devices (routers and switches, for instance) to control network traffic.

By contrast, Software-Defined Networking (SDN) uses software-based controllers to communicate with the network hardware and direct network traffic. So instead of having to programme lots of separate pieces of hardware, administrators can control their networks simply by operating a single software-based controller.

SDN was first used as a way of making the management of local networks more efficient. However, SD-WAN takes this principle and builds on it. With an SD-WAN solution, SDN creates a software-based overlay across the entire wide-area network, making it possible to manage that network much more efficiently.

What are the benefits of SD-WAN?


An SD-WAN solution will typically feature a single control hub. This makes it much easier to deploy network management policies aligned with business priorities. For example, you might instigate a rule which states that data traffic from certain user categories is sent only via secure connections. Each time you update your policy, this is immediately downloaded to all relevant devices.


With SD-WAN, traffic can be routed automatically along the most appropriate path, helping you to minimise single points of failure and maintain performance levels. A control hub also provides visibility across your IoT estate, enabling you to identify and troubleshoot connectivity bottlenecks and review the bandwidth consumed by individual IoT applications.


SD-WAN enables you to isolate IoT traffic from other forms of traffic on the network, apply your desired method of security for different categories of device, traffic and user. This helps you protect your network, reduce your risks and ensure business continuity.

Find out more

For an expert assessment of your connectivity needs and to discover the best fit M2M options for your business, speak to Wireless Logic today.

Learn more about our connectivity solutions for a wide range of use cases here.

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