Verifying and Saving Your Clock and Time Zone Configuration
Verifying and Saving Your Clock and Time Zone Configuration
Enter the following command to verify that you configured the time and time zone correctly:
show clock
The output displays the date, time, and time zone that you configured.
Configuring Network Time Protocol Support
This section provides information and instructions for configuring the system to enable the use of the Network
Time Protocol (NTP).
Important
Many of the services offered by the StarOS require accurate timekeeping derived through NTP. If the time
reference(s) used by StarOS are not accurate, the services may be unreliable. For this reason it should be
assumed that normal system operation requires that NTP be configured.
The system uses NTP to synchronize its internal clock to external time sources (typically GPS NTP sources,
or other Stratum 2 or 3 servers, switches or routers).
By default, NTP is not enabled externally and should be configured when the system is initially installed.
When enabled, the active MIO/UMIO/MIO2 will synchronize with external sources. If not enabled, the active
MIO/UMIO/MIO2 will use its local clock as a time source. In the event of an NTP server or network outage,
an already running MIO/UMIO/MIO2 will continue to use NTP to maintain time accuracy, but in a holdover
mode.
All cards with CPUs synchronize to the active MIO/UMIO/MIO2 internally. This occurs even if an external
NTP server is not configured. In the event of a MIO/UMIO/MIO2 switchover, all other cards will start
synchronizing with the newly active MIO/UMIO/MIO2 automatically.
The system should have:
• NTP enabled.
• NTP configured for use in the local context only. Use of other contexts (which can be specified in the
• NTP configured for at least three external NTP servers. With three or more servers, outlyers and broken
Important
ASR 5500 System Administration Guide, StarOS Release 21.4
44
Configure the system clock and time zone prior to implementing NTP support. This greatly reduces the
time period that must be corrected by the NTP server.
enable configurable) will cause issues.
or misconfigured servers can be detected and excluded. Generally, the more servers the better (within
reason).
Do not configure any external NTP servers using the prefer keyword. The NTP clock selection algorithms
already have the built-in ability to pick the best server. Use of prefer usually results in a poorer choice
than NTP can determine for itself.
System Settings