With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
cncSourceChangeTimeStamp
Cisco Network Clock Source Change Time Stamp
1.3.6.1.4.1.9.9.121.1.1.8
The value of sysUpTime when the most recent change of a source of network clock occurred. A value of 0 indicates that no such event has occurred since the instantiation of this object.
Back to CISCO-ATM-NETWORK-CLOCK-MIB MIB page.
IPHost Network monitor allows you to monitor cncSourceChangeTimeStamp on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco wireless switches right now.