The tunneling technology used for the fabric data plane is based on Virtual Extensible LAN (VXLAN). VXLAN encapsulation is UDP based, meaning that it can be forwarded by any IP- based network (legacy or third party) and creates the overlay network for the SD-Access fabric.
Although LISP is the control plane for the SD-Access fabric, it does not use LISP data encapsulation for the data plane; instead, it uses VXLAN encapsulation because it is capable of encapsulating the original Ethernet header to perform MAC-in-IP encapsulation, while LISP does not. Using VXLAN allows the SD-Access fabric to support Layer 2 and Layer 3 virtual topologies (overlays) and the ability to operate over any IP-based network with built-in network segmentation (VRF instance/VN) and built-in group-based policy.

There are five basic device roles in the fabric overlay:
+ Control plane node: This node contains the settings, protocols, and mapping tables to provide the endpoint-to-location (EID-to-RLOC) mapping system for the fabric overlay.
+ Fabric border node: This fabric device (for example, core layer device) connects external Layer
3 networks to the SDA fabric.
+ Fabric edge node: This fabric device (for example, access or distribution layer device) connects wired endpoints to the SDA fabric.
+ Fabric WLAN controller (WLC): This fabric device connects APs and wireless endpoints to the SDA fabric.
+ Intermediate nodes: These are intermediate routers or extended switches that do not provide any sort of SD-Access fabric role other than underlay services.

Focus on log
DHCPD: relay information option exists, but giaddr is zero
giaddr (Gateway IP Address) is a field within DHCP packets used in DHCP relay scenarios. It contains the IP address of the relay agent (gateway) that forwards the DHCP request from a client to the DHCP server. This helps the DHCP server assign appropriate IP addresses and configuration to clients on different subnets.
Add giaddr on the interface that perform DHCP.
"ip dhcp relay information trusted giaddr_IP" command, you indicate that the relay agent IP address should be included in DHCP packets as they are forwarded to the DHCP server.