Extreme Networks 200 Series - Manual (Page 85)

Using the Simple Network Time Protocol
Summit 200 Series Switch Installation and User Guide 83
for switches using SNTP to query the SNTP server(s) directly. A combination of both methods is
possible. You must identify the method that should be used for the switch being configured.
2 Configure the Greenwich Mean Time (GMT) offset and Daylight Savings Time preference. The
command syntax to configure GMT offset and usage of Daylight Savings is as follows:
config timezone <GMT_offset> {autodst | noautodst}
The GMT_OFFSET is in +/- minutes from the GMT time. Automatic Daylight Savings Time (DST)
changes can be enabled or disabled. The default setting is enabled.
3 Enable the SNTP client using the following command:
enable sntp-client
Once enabled, the switch sends out a periodic query to the SNTP servers defined later (if configured)
or listens to broadcast SNTP updates from the network. The network time information is
automatically saved into the on-board real-time clock.
4 If you would like this switch to use a directed query to the SNTP server, configure the switch to use
the SNTP server(s). If the switch listens to SNTP broadcasts, skip this step. To configure the switch to
use a directed query, use the following command:
config sntp-client [primary | secondary] server [<ip_address> | <hostname>]
NTP queries are first sent to the primary server. If the primary server does not respond within 1
second, or if it is not synchronized, the switch queries the secondary server (if one is configured). If
the switch cannot obtain the time, it restarts the query process; otherwise, the switch waits for the
sntp-client update interval before querying again.
5 Optionally, the interval for which the SNTP client updates the real-time clock of the switch can be
changed using the following command:
config sntp-client update-interval <seconds>
The default sntp-client update-interval value is 64 seconds.
6 You can verify the configuration using the following commands:
— show sntp-client
This command provides configuration and statistics associated with SNTP and its connectivity to
the SNTP server.
— show switch
This command indicates the GMT offset, Daylight Savings Time, and the current local time.
NTP updates are distributed using GMT time. To properly display the local time in logs and other
timestamp information, the switch should be configured with the appropriate offset to GMT based on
geographical location. Table 25 describes GMT offsets.
Table 25: Greenwich Mean Time Offsets
GMT
Offset in
Hours
GMT Offset
in Minutes Common Time Zone
References
Cities
+0:00 +0 GMT—Greenwich Mean
UT or UTC—Universal
(Coordinated)
WET—Western European
London, England; Dublin, Ireland;
Edinburgh, Scotland; Lisbon,
Portugal; Reykjavik, Iceland;
Casablanca, Morocco
-1:00 -60 WAT—West Africa Azores, Cape Verde Islands