The idea of network automation is not new, but new Software-Defined Networking (SDN)-based approaches make automated provisioning across the Wide-Area Network (WAN) more powerful than ever. An automated WAN provides a programmable foundation that simplifies service providers' ability to transform and offer new virtualized, on-demand services. This white paper provides an overview of SDN-based WAN automation and focuses on the drivers and benefits of WAN automation, the roles of SDN and Network Functions Virtualization (NFV) as technology enablers, challenges hindering progress towards full automation, and proposed solutions for addressing these challenges.