Allied Telesis x530L Series, Руководство по установке

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Chapter 1: Overview
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conditions, the switch can support up to eight Class 6 powered devices
with the maximum 51.3.5W or up to five Class 8 powered devices with the
maximum of 71.3W.
The x530L-18GHXm switch has one power supply. It can supply 720W of
PoE power. This is the total maximum amount of power that the switch
can supply to powered devices on the sixteen PoE++ twisted pair ports.
The number of powered devices that the switch can support at one time
will depend on their power requirements. For instance, under normal
operating conditions, the switch can support up to twelve Class 6 powered
devices with the maximum 51.3W or up to seven Class 8 powered devices
with the maximum of 71.3W.
Port
Prioritization
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 power 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.
There are three priority levels:

Critical

High

Low
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 must 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. It there is not enough power to support all of the ports set to the
High priority level, power is provided to the ports based on port number, in
ascending order.