Hi,
 
Is there a way that freeradius can tell it is a VOICE device?  Like ACS server: Cisco-AVPair = "device-traffic-class=voice".
 
Here is a link to IP Telephony In IEEE 802.1X ...
http://www.cisco.com/en/US/prod/collateral/iosswrel/ps6537/ps6586/ps6638/config_guide_c17-605524.html#wp9000357
 
Thanks a lot,
Hangjun