In an EVPN-VXLAN architecture, the interaction between the control plane (EVPN) and the data plane (VXLAN) is defined by specific functional components:
* VTEP (VXLAN Tunnel End Point): These are the entities responsible for the encapsulation and de- encapsulation of Layer 2 Ethernet frames into Layer 3 UDP/IP packets. A VTEP can be a physical switch (like a QFX or EX series) or a software-based entity. When traffic enters the fabric, the ingress VTEP wraps it in a VXLAN header; the egress VTEP removes this header before delivering it to the destination host. (Option B)
* VNI (Virtual Network Identifier): The VNI is a 24-bit field in the VXLAN header that allows for up to 16 million unique identifiers. It is used to identify specific broadcast domains (or VLANs) within the overlay network. Each VNI effectively represents a virtualized Layer 2 segment that is stretched across the Layer 3 underlay. (Option D)
* Incorrect statements: Option A is incorrect because VNIs are identifiers, not the "engine" that performs encapsulation-that is the VTEP's job. Option C is incorrect because VTEPs identify the endpoints of a tunnel, not the individual broadcast domains themselves.