Which of the following access modes can be used by leaf nodes in a data center?

VXLAN uses MAC in UDP encapsulation to extend Layer 2 networks and encapsulates Ethernet packets on IP packets. When packets are transmitted on a touted network, the intermediate touting device does not need to learn inner MAC addresses.

EVPN-VXLAN uses EVPN as the control plane and exchanges BGP EVPN routes between VTEPs to implement automatic V7EP discovery and host Information advertisement. This prevents unnecessary data traffic flooding.

The Session ID of PPPoE could be changed during the whole Session Stage.

There are two MAC address learning modes in the VPLS: unqualified and qualified. In qualified mode, all VLANs are processed by the same VSI and they share the same broadcast domain or MAC address space.