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![[NOTE: ]](images/note.gif) |
NOTE: For successful time protocol setup and specific configuration details, you may need to contact your system administrator regarding your local configuration. |
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Using time synchronization ensures a uniform time among interoperating devices. This helps you to manage and troubleshoot switch operation by attaching meaningful time data to event and error messages.
The switch offers TimeP and SNTP (Simple Network Time Protocol) and a timesync command for changing the time protocol selection (or turning off time protocol operation.)
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Select a time synchronization protocol:
SNTPorTimeP(the default.) -
Configure the remaining parameters for the time protocol you selected.
NOTE: The switch retains the parameter settings for both time protocols even if you change from one protocol to the other. Thus, if you select a time protocol, the switch uses the parameters you last configured for the selected protocol.
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![[IMPORTANT: ]](images/important.gif) |
IMPORTANT: Simply selecting a time synchronization protocol does not enable that protocol on the switch unless you also enable the protocol itself (step 2, above.) For example, in the factory-default configuration, TimeP is the selected time synchronization method. However, because TimeP is disabled in the factory-default configuration, no time synchronization protocol is running. |
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SNTP provides two operating modes:
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The switch acquires time updates by accepting the time value from the first SNTP time broadcast detected. (In this case, the SNTP server must be configured to broadcast time updates to the network broadcast address; see the documentation provided with your SNTP server application.) Once the switch detects a particular server, it ignores time broadcasts from other SNTP servers unless the configurable Poll Interval expires three consecutive times without an update received from the first-detected server. If the Poll Interval (configurable up to 720 seconds) expires three times without the switch detecting a time update from the original server, the switch accepts a broadcast time update from the next server it detects.
NOTE: To use Broadcast mode, the switch and the SNTP server must be in the same subnet.
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The switch periodically requests a time update, for the purposes of time synchronization, from the configured SNTP server. (You can configure one server using the menu interface, or up to three servers using the CLI
sntpserver command.) This option provides increased security over the Broadcast mode by specifying which time server to use instead of using the first one detected through a broadcast. The default value between each polling request is 720 seconds, but can be configured. At least one manually configured server IP address is required.