FreeNAC provides Virtual LAN assignment and LAN access control for Cisco switches based on vmps. It can also do live network end-device discovery via SNMP. 802.1x can also be used for device authentication. >
The project was frozen in 2009 and in 2015 the last reference installation was stopped. The sources are on Github https://github.com/Boran/freenac, if you wish to contribute or fork. The legacy documentation was on FreeNAC.net, but that too has been stopped.