Hello Albert
Dynamic VLANs use what is called a VLAN Membership Policy Server (VMPS), which is used to create a centralized method of selecting the VLAN for a port dynamically, based on the MAC address of the connected device. As the device moves from port to port, the assigned VLAN “follows” it as the switch dynamically assigns the proper VLAN for that particular host.
There is no lesson on NetworkLessons about VMPS, since it is not explicitly mentioned as a topic in any of the certifications included on the site, but you can take a look at this Cisco documentation for more information:
I hope this has been helpful!
Laz