Why are enterprises being drawn to software defined WANs? For starters, SD-WANs can help improve network performance (including branch office connectivity) while also streamlining costs and simplifying implementation and maintenance. According to a 2015 IHS survey of 150 North American businesses, almost half (45 percent) of respondents, eyeing these potential benefits among others, planned to spend more on SD-WAN solutions over the next two years.

SD-WAN is part of a broader recent trend of using intelligence (i.e., decision-making) to make networks more agile as well as highly responsive to ever-evolving business requirements. It is not the same as software-defined networking – the term for separating the control and forwarding planes of an IT network – although it follows similar principles of abstraction and programmability. Ultimately, enterprises expect SD-WAN, like SDN, to give them a superior, cost-effective foundation for modern real-time applications like voice and video along with cloud-based applications.

Research firm Gartner recently released a comprehensive report on current SD-WAN technologies and how they should be implemented. Let’s look at a few of the big takeaways from this document, so that it becomes easier for enterprises to understand the stakes for migrating from traditional WANs to more effective SD-WANs.

1) SD-WAN addresses problem with WAN cost, control and security
The rise of cloud computing has put mounting pressure on legacy WANs. Traffic now moves in complex patterns that may traverse data centers, branch offices and private and public cloud instances. The high costs of WAN connectivity, especially MPLS links, is increasingly difficult to foot in this context.

Moreover, the manual configuration processes long used with classic WANs are difficult to scale for today’s dynamic applications and business requirements. Automation is needed to ensure that traffic loads are moved to the most reliable, high-quality paths so as to avoid costly outages and failures.

“SD-WANs have adaptability and real-time analysis to direct network resources to applications that need them.”

At the same time, with so much traffic moving to the cloud, enterprises face an uphill climb in maintaining visibility into, and security over, their network traffic. While old-fashioned WANs were not designed with this use case in mind, SD-WANs include the adaptability and real-time analysis to best direct network resources to the applications that need them most.

2) SD-WANs are lightweight, secure and straightforward to use
To qualify as an SD-WAN, a solution must meet several basic criteria. First, it should be compatible with a variety of transport media, including broadband Internet and 4G LTE in addition to MPLS. This way, it can fall back on different channels when a particular link encounters trouble.

Second, load sharing across many WAN connections, including ones to branch offices and remote sites, should be supported. Policies for specific applications and business requirements can thus be enforced, giving priority to mission-critical programs while still supplying adequate bandwidth to less performance-sensitive ones.

Third, the SD-WAN solution should be relatively simple to configure and scale. Even personnel without years of experience with network topologies should be able to set up a branch connection that can be aligned with a particular application or initiative. Administrators can save time that would have otherwise gone toward helping with deployment.

SD-WANs are good for scaling connectivity to new branch sites.

Finally, an SD-WAN must support secure VPNs with at least 128-bit encryption. It should also be service-chainable to other network devices such as secure Web gateways and firewalls.

3) Where do SD-WANs really shine?
There are many possible use cases for an SD-WAN. A few of the most notable include:

If a company has a large number of branch offices, an SD-WAN makes it easier and more cost-effective to deliver applications like video to many or all of them.
An SD-WAN can lower the cost of equipment refreshes at these offices, and also drive down their total OPEX because it does not require numerous on-site personnel for maintenance.
The flexibility of an SD-WAN makes it ideal for the hybrid network topologies needed for supporting the integration of public cloud services into the WAN.

4) SD-WANs can provide lower costs and faster provisioning
These are two of the most prominent benefits that can be gained by SD-WAN deployment. Network changes at branches may be up to 80 percent faster thanks to simplified provisioning. Meanwhile, there is an opportunity to save on carrier services by moving away from traditional WAN architectures and to reduce the acquisition costs of both hardware and software.

5) Considerations to make during SD-WAN implementation
Prospective buyers should thoroughly vet an SD-WAN solution and consider questions such as how SD-WAN sites will interact with their non-SD-WAN counterparts and whether management capability is handled through an on-premises interface or a software-as-a-service solution.

These are just a few things to keep in mind when considering a switch to SD-WAN. Be sure to look at the full report on our website for additional information about the current SD-WAN market.