KB.15.15

3 Power Over Ethernet (PoE/PoE+) Operation

Introduction to PoE

PoE technology allows IP telephones, wireless LAN access points, and other appliances to receive

power and transfer data over existing ethernet LAN cabling. For more information about PoE

technology, see the PoE Planning and Implementation Guide, which is available on the HP

Networking website at

www.hp.com/networking/support.

PoE

Power-over-ethernet (PoE) and Power-over-ethernet plus (PoE+ or POEP) operate similarly in most

cases. The CLI commands are the same for a PoE module or a PoE+ zl module. Any differences

between PoE and PoE+ operation are noted; otherwise, the term "PoE" is used to designate both

PoE and PoE+ functionality.

Disabling or re-enabling PoE port operation

Syntax

[no] interface <port-list> power-over-ethernet

Re-enables PoE operation on <port-list> and restores the priority setting in

effect when PoE was disabled on <port-list>.

The no form of the command disables PoE operation on <port-list>.

Default: All PoE ports are initially enabled for PoE operation at Low priority. If you

configure a higher priority, this priority is retained until you change it.

NOTE: For PoE, disabling all ports allows the 22 watts of minimum PoE power

or the 38 watts for PoE+ power allocated for the module to be recovered and used

elsewhere. You must disable ALL ports for this to occur.

Enabling support for pre-standard devices

The HP switches covered in this guide also support some pre-802.3af devices.

Syntax

[no] power-over-ethernet pre-std-detect

Detects and powers pre-802.3af standard devices.

NOTE: The default setting for the pre-std-detect PoE parameter has changed.

In earlier software, the default setting is "on." In K.15.02 and later software, the

default setting is "off."

Configuring the PoE port priority

Syntax

interface <port-list> power-over-ethernet [ critical | high

| low ]

110 Power Over Ethernet (PoE/PoE+) Operation