Specifications

X723-300151 2-12 Issue 2
2.3.2 Redundant System Control Card
A second (standby) system control card may be fitted in the far left hand
(S<SYS) position of the 3200 to provide backup for the main system
controller should it fail. LK3 on both cards must be in positions 1-2 if this
facility is required. The redundant mode of operation is used to protect
against a system controller failure. One system controller will have full
control of the unit (normally the main system controller), while the other
(standby system controller) is ready to take control if the main fails or a
manual change-over occurs. The active system controller copies its
configuration data to the standby unit, allowing the off-line to take control
with minimal disruption to service.
Change-over Criteria
Main to standby changeover will occur automatically when the standby
system controller has indicated that it is operating correctly, received its
configuration information from the main unit, and one of the following
conditions occurs:
1) The main system controller suffers processor failure.
2) The main system controller reports that it has failed. This may
occur when internal self test fails.
3) The main system controller is unplugged.
4) Change-over is requested from the maintenance menu.
Once the change-over has occurred the standby system controller will take
over full control of the unit.
If the main system controller recovers, the new standby system controller
will still retain control of the unit. If the standby system controller fails
after taking control, the main system controller will then regain control.
If network management is being carried out via the rear network port
connector, the chassis must be fitted with an alarm I/O adaptor DT245 to
correctly route the management V.28 signals to the main or standby
system controller.
The green LED on the on-line system controller will be continuously 'On'.
The green LED on the standby system controller will flash.
The red Miscellaneous LED will be lit on the off-line system controller
until it has received all configuration information etc. from the main
system controller. The Miscellaneous LED will also be lit if the standby
card has failed its self test.