Comtech EF Data CRS-311 - Manual (Page 108)

CRS-311 1:1 Redundancy Switch Revision 7
Modem, RMI/TMI, and Switch Configuration MN/CRS311.IOM
4–18
Follow these steps to enable Auto On mode:
Step Task
1 Go to the CONFIG Æ AUTO menu and select AUTO ON mode.
2 Verify that the Stored Event LED stops blinking.
4.6.1.2 Set Holdoff Period
A holdoff period prevents unwarranted backups due to an intermittent fault. When in Auto
mode, additional delays may be introduced to the backup procedure by setting the number of
seconds for "holdoff" before the faulted Traffic Modem cedes operation to the Redundant
Modem (backup), or operation is returned from the Redundant Modem back to the Traffic
Modem (restore).
The process is further explained:
If a fault occurs in the Traffic Modem, and the Redundant Modem operation is fault‐free,
backup is initiated once the configured Backup Holdoff Period lapses. However, if the fault
clears within the holdoff’s configured timeframe, no transfer of operation occurs.
Similarly, if a fault occurs in the Redundant Modem while it is online, and the Traffic Modem’s
operation is fault‐free, restore is initiated once the configured Restore Holdoff Period lapses.
The default holdoff period is 10 seconds (a minimum of 1 second and a maximum of 99 seconds
is allowed).
4.6.1.2.1 Set Backup Holdoff Period
If the Traffic Modem fails, the Switch waits for the backup holdoff time to determine two things:
1) Does the Traffic Modem remain faulted?
and
2) Is the Redundant Modem not exhibiting the same fault?
If the answer is yes to both questions for the entire Backup Holdoff Period, then the Switch first
bridges the faulted Traffic Modem with the Redundant Modem. If the fault is sustained, then
the switchover to the Redundant Modem is completed and the Redundant Modem carries the
traffic.
There will be no switchover if the Redundant Modem is faulted. Ensure that the Holdoff times
are long enough (default 10 seconds) for the Redundant Modem to be configured and to lock
onto the signal.