Understanding Priority Disconnect; Setting Priority Disconnect Status; Disabling Priority Disconnect; Enabling Priority Disconnect - Alcatel-Lucent OmniSwitch 6450 User Manual

Understanding Priority Disconnect

Understanding Priority Disconnect
The priority disconnect function differs from the port priority function described on
applies only to the addition of powered devices (PDs) in tight power budget conditions. Priority disconnect
is used by the system software in determining whether an incoming PD will be granted or denied power
when there are too few watts remaining in the PoE power budget for an additional device. For example, if
there are only 2 watts available in the current PoE power budget and a user plugs a 3.5W powered device
into a PoE port, the system software must determine whether the device will be powered on. Based on
priority disconnect rules, in some cases one or more existing devices may be powered down in order to
accommodate the incoming device. In other cases, the incoming device will be denied power.
Priority disconnect rules involve the port priority status of an incoming device (i.e., low, high, and
critical), as well as the port's physical port number (i.e., 1/1). Understanding priority disconnect rules is
especially helpful in avoiding power budget deficits and the unintentional shutdown of mission-critical
devices when PDs are being added in tight power budget conditions. For detailed information on how
priority disconnect uses port priority and port number criteria for determining the power status of
incoming PDs, refer to the examples on pages
Reminder. Priority disconnect applies only when there is inadequate power remaining in the power
budget for an incoming device.
For information on setting the priority disconnect status, refer to the section below. For information on
setting the port priority status (a separate function from priority disconnect), refer to
Levels" on page 5-7.

Setting Priority Disconnect Status

By default, priority disconnect is enabled in the switch's system software. For information on changing the
priority disconnect status, refer to the information below.

Disabling Priority Disconnect

When priority disconnect is disabled and there is inadequate power in the budget for an additional device,
power will be denied to any incoming PD, regardless of its port priority status (i.e., low, high, and critical)
or physical port number (i.e., 1/4).
To disable priority disconnect, use the
you to set priority disconnect status on a slot-by-slot basis, be sure to specify the slot number in the
command line. For example, the syntax
-> lanpower 1 priority-disconnect disable
disables the priority disconnect function on slot 1.

Enabling Priority Disconnect

To enable priority disconnect, use the
number in the command line. For example, the syntax
-> lanpower 1 priority-disconnect enable
enables priority disconnect on slot 1.
page 5-8
5-9 through 5-10.
lanpower priority-disconnect
lanpower priority-disconnect
OmniSwitch 6450 Hardware Users Guide
Managing Power over Ethernet (PoE)
page 5-7 in that it
"Setting Port Priority
command. Since the switch allows
command. Be sure to specify the slot
July 2012