The primary goal of VMPS is VLAN assignment for general network management purposes, but can also be used for providing security through segregating clients with an unknown MAC address, or through further extension of the protocol to provide login for Cisco ACLs.
Only Cisco produces hardware with VMPS client functionality, and is currently fully supported across their IOS switching lines.
Cisco officially only supports the use of Catalyst 4000, 5000 and 6500 switch platforms (with appropriate firmware) as VMPS servers, but these have limited functionality, and only support a static text file transferred into them using tftp.
To enhance functionality, which can talk to SQL or use external programs to decide on network access for a given request.
The first publicly available of these was OpenVMPS, by Dori Seliskar and others, with FreeRADIUS and Icarus VMPSd available and including additional management tools to help manage hundreds or thousands of clients and MAC addresses and their VMPS support.