Why does the last reboot time for a device listed in Netreo show a different time than the device itself does?

Netreo measures the last reboot time for a system by collecting data from the system.sysUptime MIB in MIB-2. This is an industry standard and a widely supported method.

The variable collected is defined as “The time (in hundredths of a second) since the network management portion of the system was last re-initialized.” This means that if the SNMP agent on the device restarts, the counter will be reset to zero.

This counter is only 32 bits, so the largest value it can hold is 497.1 days before it rolls over. Although most devices restart periodically for updates, if your device hasn’t rebooted in a very long time, this counter will eventually roll over to zero and Netreo will show a more recent “last reboot time” than actually occurred on the device. This is a limitation of SNMP and is beyond our control.