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Cisco ONS 15530 Configuration Guide and Command Reference
78-16019-02, Cisco IOS Release 12.2(18)SV2
Chapter 3 Initial Configuration
Configuring NTP
implementation allows a machine to be configured so that it acts as though it is synchronized using NTP,
when in fact it has determined the time using other means. Other machines then synchronize to that
machine using NTP.
A number of manufacturers include NTP software for their host systems, and a version for systems
running UNIX and its various derivatives is also publicly available. This software allows host systems
to be time-synchronized as well.
Configuring NTP
NTP services are enabled on all interfaces by default. You can configure your Cisco ONS 15530 in either
of the following NTP associations:
• Peer association—This system either synchronizes to the other system or allows the other system to
synchronize to it.
• Server association—This system synchronizes to the other system, and not the other way around.
From global configuration mode, use the following procedure to configure NTP in a server association
that transmits broadcast packets and periodically updates the calendar:
For information on other optional NTP configurations, see the Cisco IOS Configuration Fundamentals
Configuration Guide.
Displaying the NTP Configuration
To view the current NTP configuration and status, use the following EXEC command:
Example
The following example shows the NTP configuration and status:
Switch# show ntp status
Clock is synchronized, stratum 4, reference is 198.92.30.32
nominal freq is 250.0000 Hz, actual freq is 249.9999 Hz, precision is 2**24
reference time is B6C04F19.41018C62 (18:21:13.253 UTC Thu Feb 27 1997)
clock offset is 7.7674 msec, root delay is 113.39 msec
root dispersion is 386.72 msec, peer dispersion is 1.57 msec
Command Purpose
Step 1
Switch(config)# ntp update-calendar Updates hardware calendar with NTP time.
Step 2
Switch(config)# ntp server ip-address Forms a server association with another system. You can
specify multiple associations.
Step 3
Switch(config)# end
Switch#
Returns to privileged EXEC mode.
Step 4
Switch# copy system:running-config
nvram:startup-config
Saves your configuration changes to NVRAM.
Command Purpose
show ntp status Displays the NTP status.