With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
busUpTime
Cisco BUS Up Time
1.3.6.1.4.1.9.9.40.1.1.1.8
The value of sysUpTime when this BUS became enabled.
Back to CISCO-BUS-MIB MIB page.
IPHost Network monitor allows you to monitor busUpTime 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.