With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
claRadiusUserName
Cisco Light Weight Access Point Protocol AAA Radius User Name
1.3.6.1.4.1.9.9.598.1.2.1.1.7
This object identifies the user for whom the request identified by the claRadiusReqId was sent.
Back to CISCO-LWAPP-AAA-MIB MIB page.
IPHost Network monitor allows you to monitor claRadiusUserName on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco firewalls right now.