What role does a Cisco SD-Access extended node serve?

An SD-Access extended node is a nonfabric-capable Layer 2 switch that connects to a fabric edge node. It allows devices connected to it to participate in the SD-Access fabric, even though the extended node itself doesn't run fabric protocols. The edge node handles the fabric encapsulation and decapsulation for traffic going to and from the extended node. This is crucial for integrating legacy or simpler switches into the SD-Access architecture. The other options are incorrect because: "Provides fabric extension to nonfabric devices through remote registration and configuration" describes a border node's role in connecting to external networks or a control plane node's role in managing devices, not an extended node. "Performs tunneling between fabric and nonfabric devices to route traffic over unknown networks" is too broad and doesn't specifically define the extended node's function; tunneling is a core fabric function, but the extended node doesn't perform it for routing over unknown networks. "Establishes Layer 3 adjacencies with unmanaged nonfabric nodes" describes a border node's function when connecting to external Layer 3 networks, not an extended node.