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How does a managed software-defined WAN service work?

Networking analyst John Burke explains managed software-defined WAN, and discusses why providers are starting to offer the service to their customers.

Managed wide area network (WAN) services are nothing new — a customer pays a service provider a flat monthly subscription fee to install, monitor and maintain networking equipment (such as routers) at branch offices. Managed service contracts typically include service level agreements, guaranteeing that customers can expect a certain degree of performance and connectivity even in remote locations.

Managed software-defined WAN (SD-WAN) services, however, are just beginning to emerge. On their own, SD-WAN technologies seek to bring the world of software-defined networking (SDN) to the edge of the WAN, with the same goals as SDN generally: decrease capital expense, decrease operating expense and increase agility and flexibility. SD-WAN also aims to make the WAN more service-centric, with traffic monitoring and management and a focus on application delivery. SD-WAN architecture can also support a control plane/data plane separation, seamless integration of WAN and branch networks into an end-to-end, policy-driven management framework, and the use of generic data-plane devices in the branch from the edge router inwards. SD-WAN seeks mainly to solve three key problems: secure integration of Internet links into well-managed WAN bandwidth pools; better align WAN architecture to network service needs; and simplify WAN management.

Cost reduction is the main driver in most organizations deploying software-defined WAN. WAN costs can be reduced by up to 90% by supplementing or replacing dedicated private WAN networks (usually MPLS) with commodity broadband connectivity.

Some carriers, like Verizon and Singtel, offer managed software-defined WAN services, freely incorporating Internet links for connectivity among internal sites. These services allow the enterprise all the flexibility and most of the cost savings of an SD-WAN environment, while minimizing the headache of managing the infrastructure and connectivity. Managed SD-WAN gives carriers a new approach to the WAN services space, recapturing business from enterprises otherwise capping, cutting back on, or simply fleeing their MPLS services.

Software-defined WAN