Allied Telesis AT-S99 - Manual (Page 26)

Chapter 1: AT-CV5M02 Management Card
26
Redundant Management Cards
You can install two AT-CV5M02 Management Cards in the AT-CV5000
Chassis. The second card functions as a backup card should the primary
management card fail or have to be removed from the chassis.
When the AT-CV5000 Chassis has two management cards, one of the
cards functions as the active card. The other is placed in a standby mode.
Your local and remote management sessions have to be performed
through the active card. You can discern the states of the cards by
examining their RDY LEDs. On the active card this LED will be on; it will
be off on the standby card.
The management cards automatically determine their active and standby
states when the chassis is powered on. Their states are based on their
chassis slot numbers. The management card in the lower numbered slot
acts as the active card and the card in the higher numbered slot functions
as the standby card. For example, if two management cards are installed
in slots 3 and 5 of the chassis, the card in slot 3 becomes the active card
and the card in slot 5 is the standby card.
The standby card continuously monitors the state of the active card over
the backplane inside the AT-CV5000 Chassis. If the active card fails or is
reset or removed from the chassis, the standby card automatically
transitions to the active state, usually within twenty seconds.
If a second management card is installed while the chassis is powered on,
the new management card is placed in the standby mode even if it
occupies a lower numbered slot than the active management card.
However, if the chassis is later power cycled or the active card is reset, the
management card in the lower numbered slot becomes the active card.
The management software has an option to force the two management
cards to change states. You might choose to use this option if the active
card is experiencing difficulties and you want to use the standby card to
perform your management tasks. The switchover, however, is not
permanent. The active and standby states are again determined
according to their slot numbers the next time the chassis is power cycled.
For instructions, refer to “Activating a Standby AT-CV5M02 Management
Card” on page 117.
The requirements and guidelines for redundant AT-CV5M02 Management
Cards are:
ˆ This feature is not supported on the AT-CV5M01 Management Card.
ˆ There can be only one redundant management card.
ˆ You can install the active and standby management cards in any of the
slots in the AT-CV5000 Chassis.