"The emergence of SD-WAN technology has been one of the fastest industry transformations we have seen in years. Organizations of all sizes are modernizing their wide-area networks to provide improved user experience for a range of cloud-enabled applications” IDC, 2018.

An SD-WAN (software-defined wide-area network) is an application of software-defined networking technology applied to WAN connections such as broadband internet, LTE, or MPLS. It connects enterprise networks—including branch offices and data centers—over large geographic distances using software-based technology to replace many features previously delivered by proprietary or specialized hardware.

New ways of doing business mean WAN networks need to change

Network managers are reconsidering their WAN architecture because of changing business needs such as collaborative working and a mobile workforce that need access to corporate resources anytime, anywhere. Added to which, business applications are increasingly cloud-based, often hosted by different suppliers, which exposes the organization to compliance issues and the increased threat of cyberattack.

Legacy WAN deployments struggle to cope with the demands of bandwidth intensive, high performance apps, which results in network congestion, dropped connections and other performance issues that make for a poor user experience.

It's also a continual battle for network managers to meet business demands while containing costs. Many enterprises have complex infrastructure at their branch offices—routers, WAN path controllers, WAN optimizers, firewalls—that is expensive to buy and maintain, and complex to manage.

SD-WAN rises to the challenge

SD-WANS are attractive because they help address those different challenges.

Simplified management: as a centralized, cloud-delivered WAN architecture, SD-WAN can easily mix and match connection types according to content type and use case priority. And they’re much quicker to implement—low or zero-touch provisioning—than traditional technologies, which typically require an on-site technician to install, and configure equipment.

Cost saving: current WAN technologies, such asMPLS, are very reliable, offering excellent quality of service (essential, to support VoIP, for example) but they’re expensive, especially for high-bandwidth usage where the cost per megabit can be prohibitive for a small office. SD-WAN doesn’t have a bandwidth penalty and, depending on the use case and site characteristics, can reduce costs by up to 60%.

Enhanced security: enabling broadband in the WAN makes the security requirements more acute and SD-Wan addresses this problem by incorporating distributed security features such as a firewall, DNS enforcement, intrusion prevention and URL filtering.

Improved user experience: WAN optimization delivers high availability to users anywhere, with predictable SLA, for all critical enterprise applications hosted in multiple clouds. In the event of link degradation or failure, application-aware routing can dynamically select the optimal path for traffic flows and load sharing.

Vendors are investing heavily in SD-WAN product lines

Cisco were one of the early champions of SD-WAN having introduced their IWAN product range in 2014, and have developed their offering through the recent acquisition of SD-WAN specialist Viptela, and continued investment in Meraki SD-WAN.

Meraki is typically for customers with more basic needs, and Cisco has simplified the product for use by IT generalists rather than network specialists. It’s a full, turnkey product that integrates with and provides end-to-end management of the Meraki range of routers, switches, Wi-Fi access points and other infrastructure. Zero-touch cloud provisioning means organizations can remotely deploy the Meraki SD-WAN quickly and manage it easily using cloud-based tools.

Viptela, on the other hand, is engineered for businesses with complex WANs that need to connect to data centers and public cloud services. One of the major advantages of the product is vManage, a centralized network management system that provides a GUI interface to monitor, configure, and maintain all Viptela devices. It provides visibility and analytics that make troubleshooting broadband and internet-based connectivity easier, giving network professionals the ability to predict when bandwidth will become an issue, so they can provision additional resources before performance degrades. The software has also been optimized with cloud apps, such as Salesforce and Office 365, in mind.

While Cisco are primarily targeting large Enterprise, Edgewater have focused on the SMB sector, citing resilience, performance and affordability as the main benefits of their SD-WAN solution. It’s integrated with the EdgeView Service Control Center giving service providers a single pane of glass for device management and troubleshooting.

Stop and think before jumping on the SD-WAN train

With changing business requirements and heavy vendor investment, it makes sense to consider SD-WAN as a solution, but we suggest a measured approach to adoption:

1. SD-WAN isn’t a silver bullet and deployment must be carefully planned. Organizations need to have a detailed networking strategy, a good understanding of the restrictions their current network imposes on meeting that strategy, and a grasp of where and how SD-WAN can help overcome those restrictions. Answer those questions before search and selection of specific products.

2. Start with a small implementation to evaluate options, risks and challenges.

3. Pick a reliable product vendor. Market growth has resulted in new start-ups appearing, but they often lack the broader enterprise networking experience of established vendors. Remember that SD-WAN won’t be implemented in a vacuum and established vendor are better placed to advise on the many integration considerations.