SD-Access uses logic blocks called fabrics which leverage virtual network overlays that are driven through programmability and automation to create mobility, segmentation, and visibility. Network virtualization becomes easy to deploy through software-defined segmentation and policy for wired and wireless campus networks. Reference: https://www.cisco.com/c/en/us/td/docs/solutions/CVD/Campus/SD-Access- Distributed-Campus-Deployment-Guide-2019JUL.html