Growing numbers of branch locations coupled with increasing reliance on cloud services has heightened demands on the wide-area network. Traditionally, branch offices could route all Internet traffic through a private WAN to the central data center because that was where business applications and data resided. However, that model has become costly, inefficient and ineffective.Today, many branch-office WANs combine private lines with broadband connections, and some rely upon broadband alone. Although the Internet doesn't meet the highest standards for availability, it has become much more stable in recent years. Adding redundant broadband connections to the WAN can boost reliability sufficiently to meet most business requirements. This enables organizations to take advantage of the cost savings associated with the Internet - broadband connections can be half as expensive as private lines.Latency-sensitive applications may need an MPLS connection to meet Quality of Service requirements. Other applications do not, however, and MPLS requirements can be reduced by routing this traffic through the Internet. This requires visibility into which data is associated with which application.A hybrid WAN can solve these problems, but it can be difficult to implement - the manual configurations required to differentiate and segment traffic are complex and time-consuming. These configurations need to be updated regularly as application profiles and business needs change, which would require IT to visit each location for every update.The software-defined WAN (SD-WAN) is an emerging technology that brings automation and centralized management to the WAN. Rather than having a single active network and a backup connection, all connections are active, and traffic is routed automatically across a hybrid network that might include broadband, MPLS, VPNs and LTE. The SD-WAN employs software-defined network principles to consolidate and abstract network functions, enabling policy-based configuration and control through software.SD-WAN reduces costs by enabling organizations to rely primarily upon broadband as opposed to more expensive MPLS links. SD-WAN is intelligent enough to know when broadband won't provide an adequate connection and reroutes traffic to MPLS on an "as-needed" basis.SD-WAN increases agility by automating complex configurations. IT only has to define and prioritize various types of traffic and routing policies instead of constantly reconfiguring devices. Routing is based upon the current state of the network, providing the flexibility to adapt to changing network conditions.SD-WAN reduces the "branch stack" by virtualizing network services. Rather than requiring IT to manage a number of appliances to provide WAN functions, SD-WAN brings these functions to one device that can be centrally managed and deployed on demand.The SD-WAN market is in its infancy, although a number of startups and established WAN optimization vendors are touting the technology. The scant market research that's available bundles SD-WAN with the broader WAN optimization category, making it difficult to chart adoption of SD-WAN solutions. Nevertheless, we believe SD-WAN is a technology to watch. This new approach promises to help organizations reduce costs, improve performance and simplify branch office IT by creating a consolidated, centrally managed and application-aware WAN platform.
