Selecting A Power Management Mode - Cisco Catalyst 4500 Series Software Configuration Manual

Power Management

Selecting a Power Management Mode

By default, a switch is set to redundant mode. In the show power command, if the
power supplies needed by system is 1, the switch is in redundant mode; if the
power supplies needed by system is 2, the switch is in combined mode.
Your switch hardware configuration dictates which power supply or supplies you should use. For
example, if your switch configuration requires more power than a single power supply provides, use the
combined mode. In combined mode, however, the switch has no power redundancy. Consider the
following possibilities:
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Power Management Limitations in Catalyst 4500 series switches
Limitation 1
It is possible to configure a switch that requires more power than the power supplies provide. The two
ways you could configure a switch to exceed the power capabilities are as follows:
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Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS 15.2(5)Ex
14-10
The supervisor engine consumes 110 W, the fan boxes for the Catalyst 4503 switch consume 30 W
each, the fan boxes for the Catalyst 4506 and Catalyst 4507 switches consume 50 W each, the
backplane for the Catalyst 4503 and Catalyst 4506 switches consumes 10 W, and the backplane for
the Catalyst 4507 switch consumes 40 W.
1000 W can support a fully loaded Catalyst 4503 switch with no powered device support.
1300 W can support a fully loaded Catalyst 4503 switch with Cisco powered devices.
Each PoE port on a WS-X4148-RJ45V module requires 6.3 W. Five fully loaded WS-X4148-RJ45V
modules in a switch comprise 240 ports. This configuration requires 1512 W of PoE, plus 300 W for
the modules.
The power requirements for the installed modules exceed the power provided by the power supplies.
If you insert a single power supply and then set the switch to combined mode, the switch displays
this error message:
Insufficient power supplies present for specified configuration.
This error message also displays in the output for the show power command. This error message
displays because, by definition, combined mode requires that two working power supplies be
installed in your switch.
If the power requirements for the installed modules exceeds the power provided by the power
supplies, the switch displays this error message:
Insufficient power available for the current chassis configuration.
This error message also appears in the show power command output.
If you attempt to insert additional modules into your switch and exceed the power supply, the switch
immediately places the newly inserted module into reset mode, and the switch displays these error
messages:
Module has been inserted
Insufficient power supplies operating.
Additionally, if you power down a functioning switch and insert an additional module or change the
module configuration so that the power requirements exceed the available power, one or more
modules enter reset mode when you power on the switch again.
The power requirements for the PoE exceed the PoE provided by the power supplies.
Chapter 14 Environmental Monitoring and Power Management