Application Note

RL; Reviewed:

WCH 10/22/2004

Solution & Interoperability Test Lab Application Notes

5 of 10

Alpine3808-PoE.doc

3. Configure Inline Power over Ethernet on the Extreme

Networks Alpine 3808

Inline Power over Ethernet (PoE) is supported on the Alpine 3808 with addition of the Alpine

FM-32Pi PoE Module. By default, PoE support is enabled on the system and on all slots. The

following commands can be used to explicitly enable PoE support on both the system and a slot

containing an Alpine FM-32Pi PoE Module.

enable inline-power

enable inline-power slot 5

Each PoE-capable port automatically detects 802.3af-compliant Powered Devices (PDs) and may

be configured to also supply power to detected PDs. The following command allows ports 1

through 16 on slot 5 to detect and supply power to PDs.

configure inline-power detection auto ports 5:1-5:16

Inline power budgeting in the Alpine 3808 is based on allocated power, not actual power

consumption. For example, a detected PD may be allocated 15.4 Watts even though it may

actually consume less than that. The Alpine 3808 can be configured to allocate power on a PoE-

capable port based on the 802.3af class of the detected PD, the configured maximum power on

the port, the greater of the class power and configured maximum power on the port, or the

maximum allowed power on the port (20 Watts). The following commands configure the Alpine

3808 to allocate power based on the detected PD’s advertised class for ports 1 through 16 on slot

5, and enable PoE support on those ports (by default, PoE support is enabled on all PoE-capable

ports).

configure inline-power violation-precedence advertise-class ports 5:1-5:16

enable inline-power ports 5:1-5:16

Alternatively, if the actual power range drawn on a PoE-capable port is known, then the Alpine

3808 may be configured to allocate power based on the actual maximum rather than the 802.3af

power class of the detected PD on the port. The following commands set the “operator-limit” on

port 17 to 5 Watts and instruct the Alpine 3808 to allocate power based on the operator-limit

value on port 17. Note that any PD that draws more than 5 Watts will be denied power if

connected to that port. Therefore, the operator-limit should be set to a value that accurately

represents the actual power required by PDs expected to connect to that port.

configure inline-power operator-limit 5000 ports 5:17

configure inline-power violation-precedence operator-limit ports 5:17

enable inline-power ports 5:17

An external 48V power source provides power to the Alpine FM-32Pi PoE Module. As shown

in the following command, the Alpine 3808’s internal power supply may be configured as a