A virtual network is not a vlan. It is called Virtual Network Overlays. See below info and link:
Network fabric: With a controller element in place, you can consider building the network in logical blocks called fabrics. The Cisco SD-Access Fabric leverages Virtual Network Overlays in order to support mobility, segmentation and programmability at very large scale. The Virtual Network Overlay leverages a control plane to maintain the mapping of endpoints to their network location up to date as end-points move around the network. Separation of the control plane from the forwarding plane reduces complexity, improves scale and convergence over traditional networking techniques. The Cisco SD-Access Fabric enables several key capabilities, such as the host mobility regardless of volume of moves and size of the network, Layer 2 and Layer 3 segmentation, and wireless integration. Other capabilities include intelligent services for application recognition, traffic analytics, traffic prioritization and steering for optimum performance and operational effectiveness.