SNTP time synchronization

SNTP provides three operating modes:

• Broadcast mode
  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.

  NOTE:

  To use Broadcast mode, the switch and the SNTP server must be in the same subnet.

• DHCP mode

  DHCP mode is enabled by default. In DHCP mode, the SNTP server address and the timezone are provided in the DHCP address reply.

• Unicast mode

  The switch requests a time update from the configured SNTP server. (You can configure one server using the menu interface, or up to three servers using the CLI sntp server 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.