Software-defined WAN solutions help to reduce costs and streamline operations through flexibility, consolidation and centralized management.
The wide-area network (WAN) has become one of the most critical components of the IT infrastructure, enabling organizations to gain access to cloud resources and connect remote locations and workers to headquarters. Most network administrators would agree that legacy WAN architectures are ill-equipped to meet today’s requirements.
Traditionally, organizations provisioned dedicated circuits or multiprotocol label switching (MPLS) links to interconnect locations, backhauling web traffic to headquarters due to the inherent unreliability of Internet connections. That worked well enough when Internet traffic primarily consisted of web browsing and email. As organizations continue to adopt Third Platform technologies — cloud, big data and analytics, mobility, and social applications — they are finding that the cost and complexity of traditional WAN models are unsustainable.
Software-defined WAN (SD-WAN) solutions are ideally suited to address these new demands. SD-WAN draws upon software-defined networking (SDN) principles to improve the manageability and reliability of the WAN. With SD-WAN, organizations can dynamically mix and match connectivity options to cut costs, enhance security and improve application performance. SD-WAN also makes it possible to consolidate network devices in branch locations, streamlining branch deployment and simplifying support.
Although SD-WAN solutions have only been commercially available for a few years, the technology's compelling value proposition has led to remarkable market growth. In a recent forecast, research firm IDC estimated that worldwide revenues for SD-WAN infrastructure and services will exceed $8 billion in 2021 — a compound annual growth rate of nearly 70 percent.
Choosing the Right Path
A key feature of SD-WAN is its ability to blend multiple transport types, such as MPLS, broadband Internet, cellular and satellite, in an active-active configuration. Software-based intelligence provides automated, policy-driven routing of traffic over the optimal connection. This enables organizations to leverage cost-efficient broadband Internet links and reduce their reliance on expensive MPLS.
That simply would not be possible in a traditional WAN environment. The configurations required to differentiate and segment traffic in the hybrid WAN would have to be applied manually to devices at each location and updated regularly as application profiles and business needs changed.
SD-WAN automates all of that with a centralized, application-based policy controller and a secure software overlay that abstracts the underlying networks, with analytics for application and network visibility. These technologies provide intelligent path selection across WAN links, based on the application policies defined on the controller and the current state of the network. Administrators simply define and prioritize various types of traffic, and the WAN adapts to changing network conditions.
“Traditional WANs were not architected for the cloud and are also poorly suited to the security requirements associated with distributed and cloud-based applications,” said Rohit Mehra, vice president, Network Infrastructure at IDC. “And while hybrid WAN emerged to meet some of these next-generation connectivity challenges, SD-WAN builds on hybrid WAN to offer a more complete solution.”
Some IT industry pundits speculated that SD-WAN would spell the ultimate demise of MPLS. Organizations could implement multiple broadband links for greater resilience instead of backhauling WAN traffic to headquarters. However, most organizations have deployed broadband alongside MPLS. Dedicated connections can be reserved for latency-sensitive applications and sensitive data, and broadband used for cloud-based applications.
Simplicity and Security
Many SD-WAN solutions also virtualize a number of network functions, including WAN optimization and firewall capabilities. All of this functionality is combined in one device that can be centrally managed and deployed on demand.
This ability to reduce WAN complexity is a primary driver of SD-WAN adoption, according to a global study conducted by Dimensional Research. Growing numbers of network devices have increased the time to provision branch locations, with 32 percent of organizations surveyed saying it took longer than a month. More than 85 percent of organizations are considering SD-WAN specifically to reduce network appliance sprawl and increase security.
Fifty-seven percent of organizations said their primary motivation for SD-WAN adoption was increased risk that comes with direct Internet connection at the branch. Seventy-four percent said they utilize a direct Internet connection and must deploy more devices to combat threats. Sixty-eight percent said that deploying and managing network security devices at branch locations was the most challenging aspect of WAN management.
In addition to consolidating WAN devices in branch locations, SD-WAN can improve security by simplifying site-to-site VPN connections. SD-WAN also enables WAN segmentation — a complex proposition with traditional architectures.
The benefits of SD-WAN include cost-effective delivery of business applications, optimization of cloud-based services, improved branch-IT efficiency and enhanced security. These benefits have resonated across a broad spectrum of organizations, ensuring continued rapid uptake for this new way to WAN.