Why network nerds are so excited about SD-WAN - TechCentral

Why network nerds are so excited about SD-WAN

Robert Marston

The concept of virtualisation is coming to the wide-area network, promising to give enterprises a more agile, cost-effective and resilient approach to managing their network infrastructure. The concept of the software-defined WAN (SD-WAN) is maturing at a rapid rate, meaning that the technology will soon hit the mainstream in South Africa.

SD-WAN is one of the hottest growth spots in the technology market worldwide. International Data Corp forecasts that the market will grow from US$225m in 2015 to $1.2bn by the end of this year. For the next five years, SD-WAN sales will grow at a 69% compound annual growth rate to reach $8bn in 2021.

Most IT managers and CIOs are by now familiar with the concept of a software-defined network (SDN), which aims to make local-area and campus networks as flexible as virtualised servers and storage. It allows administrators to shape traffic and provision network services instantaneously without concerning themselves with changing the physical infrastructure because it separates the network hardware from the software used to manage it.

SD-WAN applies a similar concept to WAN connections, enabling companies to separate WAN links (across large geographic distances such as between branch offices and data centres) from services such as bandwidth optimisation, network monitoring, application filtering and traffic prioritisation.

SD-WAN usually takes the form of a network appliance deployed on the customer premises — a software-driven device that combines functionality such as routing, security (firewall) and WAN acceleration. These appliances are flexible, simple to configure and easy to manage via simple Web-based interfaces.

What this means in practice is that organisations can aggregate and manage multiple different types of WAN connections — MPLS, broadband, 3G,4G/LTE — as a virtualised pool of connectivity. This, in turn, empowers network administrators to dynamically adjust to changing application or user requirements without necessarily needing to upgrade bandwidth. It finally allows enterprises to co-ordinate and control network changes dynamically and automatically by themselves and in line with IT and link service changes, such as moving traffic from a failed link to another link.


Benefits include simpler deployment of wide-area and cloud-access networks, vs traditional WAN configurations such as MPLS, as well as a better end-user experience for applications such as voice-over-IP, videoconferencing and apps accessed across a private cloud or the public cloud. SD-WAN will thus play an invaluable role as enterprises adopt more and more bandwidth-intensive cloud applications that demand high reliability and excellent quality of service. Some benefits of SD WAN include:

Resilience: You can easily switch users or applications from one network provider or technology to another in the event of a network outage or service degradation.

Intelligent routing of network traffic: You can take advantage of the right connection or transport protocol for the job or app — for example, you can switch high-priority traffic such as voice and video through the WAN link that offers the best quality of service. You can set policies by factors such as IP address, application, port number, quality-of-service requirements, and time of day.

Security: Aggregating WAN connections on one appliance improves network security while reducing the complexity associated with managing customer premises equipment from multiple service providers and vendors.

Simpler service provisioning: SD WAN makes it easier to provision services and configure branch networks. SD-WAN provides the ability for IT managers to provision network changes based on application performance, yet still allow network administrators the ability to control and optimise overall network performance.

Reduced WAN costs: One can use lower-priced broadband services where appropriate, such as with general Internet data, and push critical traffic, such as voice, through MPLS WAN links without having to scale up on the MPLS bandwidth and costs. SD-WAN also enables customers to easily provision their own secure VPN tunnels, on demand, over existing broadband Internet connections.

The biggest challenges to wide adoption of SD-WAN include the existing investments most companies have made in legacy technologies, as well as the immaturity of the market. There are many vendors on the bandwagon and standards have yet to be settled. However, the Metro Ethernet Forum is extending its work to standardise SD-WAN managed services, which will help bring clarity to the market.

SD-WAN is set to deliver great benefits to any company with geographically dispersed branches, a large remote or mobile workforce, or a large population of users that access cloud applications. It is an exciting opportunity for telecoms providers and their customers alike.

  • Robert Marston is global head of product at Seacom

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