Availability Features
The OmniSwitch 7700 and 7800
page 1-6
OmniSwitch 7700/7800 Hardware Users Guide
April 2005
Power Checking Sequence
The power checking sequence is another built-in Availability feature. This feature helps regulate power in
the switch whenever the switch is booted or an NI module is installed in the chassis.
The sequence is a joint effort between the CMM, the NI modules, and the power supplies. During the boot
sequence, the primary CMM automatically compares the power consumption required by installed NIs
with the power available from the power supplies. If there is not adequate power to support all NIs, the
CMM will power on only the supported number of NIs, starting from the first NI slot position.
Important.
During the power checking sequence, CMMs receive priority and are always powered on. NI
modules are then powered on sequentially by slot position. In other words, the NI in slot 1 is powered on,
then slot 2, then slot 3, etc. For information on slot positions, refer to
Installing a New NI into a Running Chassis
When an NI module is installed in the chassis, only a small portion of the circuitry is initially powered up.
The CMM immediately reads the incoming module’s ID and determines how much power the module will
require. If the number of power supplies installed in the chassis can provide sufficient power, the CMM
turns on the incoming module. If the number of installed power supplies cannot provide sufficient power,
the incoming NI will remain powered off.
