Which technology underpins the Cisco SD-Access data plane?

VXLAN (Virtual Extensible LAN) is the foundational encapsulation protocol for the Cisco SD-Access data plane. It extends Layer 2 segments over a Layer 3 underlay network, creating an overlay that allows for scalable and flexible network virtualization. Each virtual network in SD-Access, known as a Virtual Network (VN), is mapped to a unique VXLAN Network Identifier (VNI), providing segmentation and isolation. LISP (Locator/ID Separation Protocol) is used in SD-Access for the control plane, managing endpoint identity and location, but not for data encapsulation. 802.1Q is a standard for VLAN tagging, primarily used for traditional Layer 2 segmentation within a single broadcast domain, not for overlay networking across a Layer 3 underlay. IPsec is a suite of protocols used for securing IP communications, providing encryption and authentication, but it is not the primary data plane encapsulation protocol for SD-Access.