Power Budget; Port Prioritization - Allied Telesis AT-GS924MX Installation Manual

Power Budget

The AT-GS924MPX and AT-GS948MPX Switches have a power budget of
370 watts. This is the maximum amount of power the switches can provide
at one time to the powered devices.
The power requirements of the PoE devices determine the maximum
number of devices the switch can support at one time. So long as the total
power requirements of the powered devices is less than the power budget
of the switch, the switch can supply power to all the devices. But if the total
power requirements exceed the power budget, the switch denies power to
one or more ports using a mechanism referred to as port prioritization.
To determine whether the power requirements of the PoE devices you
plan to connect to the switch exceed its power budget, refer to their
documentation for their power requirements and add the requirements
together. The switch should be able to power all the devices
simultaneously as long as the total is below its power budget. If the total
exceeds the available power budget, you should consider reducing the
number of PoE devices so that all of the devices receive power.
Otherwise, the switch powers a subset of the devices, based on port
prioritization.
The switch can handle different power requirements on different ports.
This enables you to connect different classes of PoE equipment to the
ports on the switch.
Port
If the power requirements of the powered devices exceed the switch's
power budget, the switch denies power to some ports based on a system
Prioritization
called port prioritization. You may use this mechanism to ensure that
powered devices critical to the operations of your network are given
preferential treatment by the switch in the distribution of power should the
demands of the devices exceed the available capacity.
There are three priority levels:
Ports set to the Critical level, the highest priority level, are guaranteed
power before any of the ports assigned to the other two priority levels.
Ports assigned to the other priority levels receive power only if all the
Critical ports are receiving power. Ports that are connected to your most
critical powered devices should be assigned to this level. If there is not
enough power to support all the ports set to the Critical priority level, power
is provided to the ports based on port number, in ascending order.
The High level is the second highest level. Ports set to this level receive
power only if all the ports set to the Critical level are already receiving
power. If there is not enough power to support all of the ports set to the
Critical

High

Low

AT-GS900MX Series Installation Guide for Stand-alone Switches
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