Digi Connect WAN Series User Manual page 121

Digi Connect WAN Family web interface
On a device with a real-time clock and no configured clock source, time and date are also local to the
device but they are meaningful because they are persistent. The offset option could be useful in
adjusting for daylight savings time. Setting the date and time to standard time and setting offset to 1
whenever daylight savings time is in effect would serve that purpose.
On a device with a configured clock source, time and date received from a clock source is expected to
be UTC. For users with several devices in different time zones, keeping offset=00:00 might be useful
for comparing logs or traces from different devices, since all would be using UTC.
Time source settings
The time source settings configure access to up to five external time sources that you can use to set
and maintain time on the device.
Type: Specifies the type of time source for this entry.
n
sntp server: The device uses its SNTP client to poll the NTP/SNTP server, specified by the
l
FQDN, for time.
cellular: The device polls the cellular service for time.
l
Interval: Specifies the interval in seconds between polls of a time source. Interval can range
n
from 1 second to 31536000 seconds. If more than one time source is specified, time sources
with shorter intervals have greater influence on the device's time than do sources with longer
intervals.
FQDN: Specifies the fully-qualified domain name or IP address for the time source. Use FQDN
n
only if the time source is SNTP.
The only time source that is guaranteed to be present on all products at all times is the system clock.
It counts uptime and displays system time as the Unix Epoch (00:00:00 on January 1, 1970) plus
uptime. Any source that is not the system clock is considered an external source. This includes the
RTC.
Devices which have an RTC but have no external time sources configured will display system time as
the Unix Epoch plus the time since power was initially applied to the device until system time is set
manually. You can manually set system time via the CLI, Web UI, and so on. Once system time is set
manually, the RTC will continue to maintain system time but, due to variations in the accuracy of the
RTC, system time can diverge from external time.
Specifying an external time source allows the device to compare its system time to the time reported
by the configured time sources and appropriate adjustments to system time. This allows system time
to stay consistent over long durations.
The polling interval for an external source establishes its priority relative to other sources; the more
samples taken from a time source, the greater influence that time source has on system time.
Any time adjustment will update the RTC automatically. All time sources are assumed to be UTC.
Time Source Global settings
Use the Time Source Global settings to configure the global settings that control time source
management.
Time Adjustment Threshold: A value in seconds that defines a range around the current time
n
value maintained by the device. If the Digi device receives a time update from a best (smallest
value) ranking time source and the new time is within that range, the Digi device's time is not
changed. However, if the new time falls outside the defined threshold range, the Digi device's
time is updated immediately using the new time value.
Digi Connect WAN Family User Guide
Configuration through the web interface
121