Administrator's Guide

Features and technical reference
555-233-5061890 Issue 5 October 2002
Setting time of day clock synchronization
The recommended configuration for ASA PC and time synchronization:
1. The PC clock is to be set to the local time including applying the local
daylight savings time (DST) rule.
2. The offset for each switch is to be set based on the difference between the
local ASA PC standard time and the switch standard time (for example, use
offset of “plus 1 hour” if ASA PC standard time is 02:00 when the switch
standard time is 03:00 per existing operation.
3. Schedule the task to occur no more often than every 24 hours at a low
traffic time period based on the local time at the switch and in the middle of
a BCMS/CMS interval being used at the switch (for example, 11:07 PM or
3:07 AM). Also the time picked should not be set to a time period when
MultiVantage nightly maintenance is scheduled to be run or the BCMS
next day period starts. Note that the time ASA uses to decide when to send
the time change is based on the local PC time including DST when
applicable. Therefore the start time and interval entered for a switch must
be based on the switch local time converted to the PC local time.
Running the task more frequently (for example, every 12 hours) makes it
more difficult to have it run during a low traffic period or it could cause the
scheduled time to occur at different times during the day as time goes on
(for example, picking any entry other than Every 24 hours or 12 hours will
make the scheduled time “creep” over the day by the selected time interval
since only the start date-time and repeat interval can be specified). The use
of the Weekly or Monthly Recurrence Patterns does not have the “creep”
problem.
4. Note that ASA must be running and OSSI connectivity to the switches
must be available (via LAN or dialup) during the scheduled times for
synchronizing the MultiVantage switches that it manages.