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CHAPTER
8-1
Software Configuration Guide—Release 12.2(25)SG
OL-7659-02
8
Configuring Power over Ethernet
Note Before reading this chapter, read "Preparing for Installation” section of the
Catalyst 4500 Series Installation Guide. It is important to ensure that your installation site has enough
power and cooling to accommodate the additional electrical load and heat introduced by PoE.
This chapter describes how to configure Power over Ethernet (PoE) on the Catalyst 4500 series switch.
This chapter contains the following sections:
• Power Management Modes, page 8-2
• Configuring Power Consumption for Powered Devices on an Interface, page 8-3
• Displaying the Operational Status for an Interface, page 8-6
• Displaying the PoE Consumed by a Module, page 8-7
The Catalyst 4500 series switch provides support for Power over Ethernet (PoE) for both Cisco
Prestandard PoE and the IEEE 802.3af standard (ratified in 2003). PoE is supported by all Catalyst 4500
series chassis and requires a PoE module and power supply. The amount of PoE power available depends
on the PoE capabilities of individual power supplies. Support for PoE allows the system to power inline
devices, such as IP phones, IP video phones, and wireless access points over standard copper cabling
(Category 5, 5e, or 6 cabling).
In addition, with PoE, you do not need to provide wall power for each PoE enabled device. This
eliminates the cost for additional electrical cabling that would otherwise be necessary for connected
devices. Moreover, PoE allows you to isolate critical devices on a single power system, enabling the
entire system to be supported by UPS backup.
You typically deploy a Catalyst 4500 series switch in one of two deployment scenarios. The first scenario
is data-only, which requires power to operate the switch and the associated modules. The second scenario
supports data and PoE (also termed “inline power”) for deployments where the attached device derives
power from the Ethernet port.
Catalyst 4500 series switches can sense if a powered device is connected to a PoE module. They can
supply PoE to the powered device if there is no power on the circuit. (If there is power on the circuit, the
switch does not supply it.) The powered device can also be connected to an AC power source and supply
its own power to the voice circuit.
Note For complete syntax and usage information for the switch commands used in this chapter, refer to the
Catalyst 4500 Series Switch Cisco IOS Command Reference and related publications at
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/index.htm.