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Catalyst 2960 POE Consumption

Hi,

I've been advised by a third party vendor to put my catalyst 2960 poe switch into consumption mode. Is that possible with this model?

Thanks,

2 REPLIES
Cisco Employee

This is what you can do

This is what you can do:

Supported Protocols and Standards

The switch uses these protocols and standards to support PoE:

CDP with power consumption—The powered device notifies the switch of the amount of power it is consuming. The switch does not reply to the power-consumption messages. The switch can only supply power to or remove power from the PoE port.

Cisco intelligent power management—The powered device and the switch negotiate through power-negotiation CDP messages for an agreed power-consumption level. The negotiation allows a high-power Cisco powered device, which consumes more than 7 W, to operate at its highest power mode. The powered device first boots up in low-power mode, consumes less than 7 W, and negotiates to obtain enough power to operate in high-power mode. The device changes to high-power mode only when it receives confirmation from the switch.

High-power devices can operate in low-power mode on switches that do not support power-negotiation CDP.

Cisco intelligent power management is backward-compatible with CDP with power consumption; the switch responds according to the CDP message that it receives. CDP is not supported on third-party powered devices; therefore, the switch uses the IEEE classification to determine the power usage of the device.

IEEE 802.3af—The major features of this standard are powered-device discovery, power administration, disconnect detection, and optional powered-device power classification. For more information, see the standard.

IEEE 802.3at (Catalyst 2960-S only)—This PoE+ standard supports all the features of 802.1af and increases the maximum power available on each PoE port from 15.4 W to 30 W.

Powered-Device Detection and Initial Power Allocation

The switch detects a Cisco pre-standard or an IEEE-compliant powered device when the PoE-capable port is in the no-shutdown state, PoE is enabled (the default), and the connected device is not being powered by an AC adaptor.

After device detection, the switch determines the device power requirements based on its type:

A Cisco pre-standard powered device does not provide its power requirement when the switch detects it, so a Catalyst 2960 switch allocates 15.4 W as the initial allocation for power budgeting; a Catalyst 2960-S switch allocates 30 W (PoE+).

The initial power allocation is the maximum amount of power that a powered device requires. The switch initially allocates this amount of power when it detects and powers the powered device. As the switch receives CDP messages from the powered device and as the powered device negotiates power levels with the switch through CDP power-negotiation messages, the initial power allocation might be adjusted.

The switch classifies the detected IEEE device within a power consumption class. Based on the available power in the power budget, the switch determines if a port can be powered. Table 12-1 lists these levels.

 

Table 12-1 IEEE Power Classifications 

Class
Maximum Power Level Required from the Switch

0 (class status unknown)

15.4 W

1

4 W

2

7 W

3

15.4 W

4

30 W (Catalyst 2960-S only)

 
 
Cisco Employee

http://www.cisco.com/c/en/us

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst2960/software/release/12-2_44_se/configuration/note/ol14988.html#wp1030360

power inline consumption

Use the power inline consumption global or interface configuration command to override the amount of power specified by the IEEE classification for the device by specifying the wattage used by each powered device. Use the no form of this command to return to the default power setting.

power inline consumption default wattage

no power inline consumption default

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