Which of the following statements about basic concepts in data center network is incorrect?

A leaf node is a fabric network function access node and provides various network devices to access a VXLAN network

Spine nodes are core nodes on the fabric network. They provide high-speed IP forwarding and conned to leaf nodes using high-speed interfaces in any scenario, spine nodes do not need to support VXLAN

The overlay technology is a tunnel encapsulation technology, such as VXLAN The basic principle is that packets are encapsulated in tunnel encapsulation mode, transparently transmitted on the underlying network, and then decapsulated to obtain original packets after reaching the destination. This is equivalent to a network overlay (overlay) on the underlying network.

The underlay network is a bearer network consisting of various physical devices, such as TOR switches, aggregation switch core switches, load balancing devices and firewalls