Users Guide

428 Managing General System Settings
SDM Template Configuration Guidelines
When the switch is configured to use an SDM template that is not currently
in use, the switch must be reloaded for the configuration to take effect.
If the IPv4 Routing or IPv4 Data Center template is currently in use and the
administrator attempts to configure IPv6 routing features without first
selecting the Dual IPv4-IPv6 Routing template, the IPv6 commands do not
take effect. IPv6 features are not available when an IPv4-only template is
active.
Why is the System Time Needed?
The switch uses the system clock to provide time stamps on log messages.
Additionally, some show commands include the time in the command
output. For example, the show users login-history command includes a Login
Time field. The system clock provides the information for the Login Time
field.
How Does SNTP Work?
SNTP assures accurate switch clock time synchronization. Time
synchronization is performed by a network SNTP server.
Time sources are established by Stratums. Stratums define the accuracy of
the reference clock. The higher the stratum (where zero is the highest), the
more accurate the clock. The switch is at a stratum that is one lower than its
time source. For example, if the SNTP server in an internal network is a
Stratum 3 device, the switch is a Stratum 4 device.
The switch can be configured to request the time from an SNTP server on the
network or it can receive SNTP broadcasts.
NOTE: If a unit is attached to a stack and its template does not match the stack's
template, then the new unit will automatically reboot using the template used by
the management unit. To avoid the automatic reboot, you may first set the
template to the template used by the management unit. Then power off the new
unit, attach it to the stack, and power it on.