From the accuracy log of a Bridge, you can view its check-in history and NTP drift and accuracy details.
Go to Devices > Bridges.
From the list select the Name link of the Bridge. Its profile is displayed.
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From the Accuracy Log option, select View.
Column
Definition
Date/Time
Date and time the device last checked-in to OneVue.
Gateway ID
Gateway ID (MAC address) of the device. Selecting the link opens the gateway profile.
Drift (sec)
The number of seconds of free running time drift that occurred between the last time synchronization with an NTP Server.
Free running time drift is how many seconds the internal time keeping drifted off from its last time sync (check-in) with an NTP Server. As an example, if a device checks-in once a day at the same time every day and the drift is 0.35 seconds, this indicates in the last 24 hours the device drifted 0.35 seconds or 1.46 milliseconds per hour from its last NTP time sync.
A drift less than one second per day is normal. More than one second may indicate a hardware problem. Devices often drift differently depending on their quality, battery power, and surrounding temperature and other environmental variables. Thus, the same device can have different drift rates at different occasions.
Unavailable indicates during its connection to an NTP Server, it failed to obtain time or was invalid.
NTP Accuracy (sec)
The Accuracy Log details the accuracy of the NTP time received during each check-in. The accuracy value takes into account the internal time accuracy of the NTP Server, as well as any network delays. This information can also be used to review the check-in history of a device.
Using an internal Stratum 1 time server gives the lowest, best time accuracy possible.
External Servers or servers that are not properly synchronized to a time reference typically yield higher less accurate values.
Less than 200ms is normal. If greater than 200ms the use of an internal NTP Server is recommended.
Unavailable indicates during its connection to an NTP Server, it failed to obtain time or was invalid.