VMPS enables the dynamic assignment of switch ports to VLANs, based on the source MAC address of the device connected to the port. When a host is moved from a port on one switch in the network to a port on another switch in the network, the switch dynamically assigns the new port to the proper VLAN for that host.
For step-by-step instructions on how to configure a Cisco Catalyst switch as a VLAN Management Policy Server (VMPS), refer to
http://www.cisco.com/en/US/docs/switches/lan/catalyst5000/catos/4.5/configuration/guide/vmps.html#wp20740