When configuring PoE, go to these sections
for information you are interested in:
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PoE
Overview
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PoE
Configuration Task List
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Configuring
the PoE Power
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Configuring
a PSE
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Configuring
a PoE Interface
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Configuring
PoE Power Management
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Configuring
PoE Monitoring
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Enabling
the PSE to Detect Nonstandard PDs
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Displaying
and Maintaining PoE
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PoE
Configuration Example
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Troubleshooting
PoE
1.1 PoE
Overview
1.1.1 Introduction
to PoE
Power over Ethernet (PoE) means that power
sourcing equipment (PSE) supplies power to powered devices (PDs) such as IP
telephone, wireless LAN access point, and web camera from Ethernet ports
through twisted pair cables.
A PoE device can provide 48 VDC power to
its PDs and provide power supply monitoring and PD priority management.
Among the interface
cards for S9500 Series Routing Switches, the LSB1GV48DB and LSB2GV48DA
interface cards support PoE.
I. Advantages
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Reliable: Power is supplied in a centralized way
so that it is very convenient to provide a backup power supply.
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Easy to connect: A network terminal requires
only one Ethernet cable, but no external power supply.
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Standard: In compliance with IEEE 802.3af, a
globally uniform power interface is adopted.
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Promising: It can be applied to IP telephones,
wireless LAN access points (APs), portable chargers, card readers, web cameras,
and data collectors.
II. Composition
A PoE system consists of PoE power, PSE,
and PD.
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PoE power
The whole PoE system is powered by the PoE
power, which includes external PoE power and internal PoE power.
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PSE
PSE is an entity used to manage PoE for
ports on a card or subcard. The PSEs on cards/subcards manage the PoE
interfaces on their own cards/subcards independently. Through the PoE interface
cables, a PSE detects PDs, classifies them, supplies power to them, and stops
supplying power to a PD when it detects that the PD is removed.
An Ethernet interface with the PoE
capability is called a PoE interface. Currently, a PoE interface can be an FE
(Fast Ethernet) or GE (Gigabit Ethernet) interface.
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PD
A PD is a device accepting power from a
PSE. There are standard PDs and nonstandard PDs. A standard PD refers to the
one that complies with IEEE 802.3af. The PD that is being powered by the PSE
can be connected to other power supply unit for redundancy backup.
The protocol specification related to PoE
is IEEE 802.3af.
Complete these tasks to configure PoE:
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When the PoE power is shut down or unavailable,
all PoE related configuration commands will fail.
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Turning off the PoE power during the startup of
the device might result in the failure to restore the PoE configuration.
The maximum PoE
power refers to the maximum power that the device can provide for all PSEs. To
avoid a power failure to the PSE owing to overload, the power consumption of
all PSEs should not exceed the maximum power of the device.
Follow these steps to configure the PoE
power:
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To do…
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Use the command…
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Remarks
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Enter system view
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system-view
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—
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|
Configure the maximum PoE power
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poe power max-value max-power
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Optional
The default maximum PoE power is 1125 for
220 VAC input and 562 for 110 VAC input.
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In the case of 220 VAC input, when the switch
uses single or dual power supply modules, you can set at most 2250 W as the
maximum PoE power; when the switch uses triple power modules, you can set at
most 4500 W as the maximum PoE power.
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In the case of 110 VAC input, when the switch uses
single or dual power supply modules, you can set at most 1125 W as the maximum
PoE power; when the switch uses triple power modules, you can set at most 2250
W as the maximum PoE power.
1.4
Configuring a PSE
Follow these steps to configure a PSE:
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To do…
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Use the command…
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Remarks
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Enter
system view
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system-view
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—
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|
Enable PoE
for a PSE
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poe
enable pse pse-id
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Required
By
default, PoE is disabled for a PSE.
|
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Configure
the maximum PoE power of a PSE
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poe
max-power max-power pse pse-id
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Optional
The
max-power argument ranges from 37 to 806, in watts.
By
default, the maximum PoE power of a PSE is 806 W.
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Ensure that the sum of maximum power of all the
PSEs on the device does not exceed the maximum power of the PoE power. When the
remaining power of the PoE power is lower than the maximum power of a PSE, PoE
is disabled for the PSE.
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The maximum power of the PSE must be greater
than or equal to the sum of maximum power of all critical PoE interfaces on the
PSE so as to guarantee the power supply to these PoE interfaces.
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To ensure power supply to the last PD and
provide redundant power to prevent sudden increase of the power, 19 watts guard
band will be reserved for the interface by default. That is, if the configured
maximum power of the PSE is 119 W, the PSE can supply 100 W power to the PD.
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The relation between the ID and slot number of a
PSE is: PSE ID = SlotNo × 3 +
1.
1.5 Configuring a PoE Interface
You can configure a PoE interface in either
of the following two ways:
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Adopt the command line.
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Configure a PoE configuration file and apply the
file to the specified PoE interface(s).
Usually, you can adopt the command line to
configure a single PoE interface, and adopt a PoE configuration file to
configure multiple PoE interfaces at the same time.
Caution:
You can adopt either mode to configure, modify, or delete a PoE
configuration parameter under the same PoE interface.
For the
S9500 series, PoE interfaces can only use signal cables to supply power.
1.5.1 Configuring a PoE Interface Through
the Command Line
Follow these steps to configure a PoE
interface through the command line:
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To do…
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Use the command…
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Remarks
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Enter system view
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system-view
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—
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|
Enter PoE interface view
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interface interface-type
interface-number
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—
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|
Enable PoE
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poe enable
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Required
By default, PoE is disabled on the PoE
interface.
|
|
Configure the maximum power for the PoE
interface
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poe max-power max-power
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Optional
By default, the maximum power on the PoE
interface is 15,400 milliwatts.
|
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Configure the PoE mode for the PoE
interface
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poe mode signal
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Optional
By default, the PoE mode is signal
(power over signal cables).
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Configure a description for the PD
connected to the PoE interface
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poe pd-description string
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Required
By default, no description is configured.
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A PoE configuration file is used to
configure at the same time multiple PoE interfaces with the same attributes to
simplify operations. This configuration method is a supplement to the common
command line configuration.
Commands in a PoE configuration file are
called configurations.
Follow these
steps to configure PoE interfaces through a PoE configuration file:
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To do…
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Use the command…
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Remarks
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Enter system view
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system-view
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—
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|
Create a PoE configuration file and enter
PoE configuration file view
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poe-profile profile-name [ index ]
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Required
|
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Enable PoE for the PoE interface
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poe enable
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Required
By default, PoE is disabled on a PoE
interface.
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Configure the maximum power for the PoE
interface
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poe max-power max-power
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Optional
By default, the maximum power on the PoE
interface is 15,400 milliwatts.
|
|
Configure the PoE mode for the PoE
interface
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poe mode signal
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Optional
By default, the PoE mode is signal
(power over signal cables).
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Return to system view
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quit
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—
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Apply the PoE configuration file to the
PoE interface(s)
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Apply the PoE configuration file to one
or more PoE interfaces
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apply poe-profile { index
index | name profile-name } interface interface-range
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Use either approach
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Apply the PoE configuration file to the
current PoE interface in PoE interface view
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interface interface-type interface-number
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apply poe-profile { index
index | name profile-name }
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Caution:
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Before you can configure another PoE
configuration file on a POE interface, you should first remove the original PoE
configuration file applied to the PoE interface; otherwise, your configuration
will fail.
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If a PoE configuration file is already applied
to a PoE interface, you must execute the undo apply poe-profile command
to remove the application to the interface before deleting or modifying the PoE
configuration file.
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You must use the same mode (command line or PoE
configuration file) to configure the poe max-power and poe
priority commands.
1.6 Configuring PoE Power Management
PoE power
management involves PSE power management and PD power management.
Where the maximum PoE power may be lower
than the sum of the maximum power required by all PSEs, PSE power management is
applied to guarantee power supply to important PSE. Where the maximum PoE power
of the device is higher than the sum of the maximum power required by all PSEs,
it is unnecessary to enable PSE power management.
Power supply to the PSE is subject to PSE
power management policies.
When the PoE power supplies power to the
PSE,
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By default, no power will be supplied to new PSE
when the PoE power is overloaded.
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Under the control of a priority policy, the PSE
with a lower priority is first disconnected to guarantee the power supply to
the new PSE with a higher priority when the PoE power is overloaded.
The power priority levels of PSE include
critical, high and low in descending order.
If the guaranteed remaining PoE power
(guaranteed maximum PoE power – power allocated to the critical PSE,
regardless of whether PoE is enabled for the PSE) is lower than the maximum
power of the PSE, you will fail to set the power priority of the PSE to critical.
Otherwise, you can succeed in setting the power priority to critical, and
this PSE will preempt the power of the PSE with a lower priority level. In the
latter case, the PSE whose power is preempted will be disconnected, but its
configuration will remain unchanged. After you change the priority of the PSE
from critical to a lower level, other PSEs will have an opportunity of
seizing power.
I. Configuration prerequisites
Enable PoE for the PSE.
II. Configuration procedure
Follow these steps to configure PSE power
management:
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To do…
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Use the command…
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Remarks
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Enter system view
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system-view
|
—
|
|
Configure the power priority for the PSE
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poe priority { critical | high | low } pse pse-id
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Optional
By default, the power priority level of
the PSE is low.
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Configure a PSE power management priority
policy
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poe pse-policy priority
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Optional
By default, no PSE power management
priority policy is configured.
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The power priority of a PD depends on the
priority of the PoE interface. The priority levels of PoE interfaces include
critical, high and low in descending order. Power supply to a PD is subject to
PD power management policies.
all PSEs implement the same PD power
management policies. When the PSE supplies power to a PD,
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By default, no power will be supplied to a new
PD if the PSE power is overloaded.
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Under the control of a priority policy, the PD
with a lower priority is first powered off to guarantee the power supply to the
new PD with a higher priority when the PSE power is overloaded.
If the guaranteed remaining PSE power
(maximum PSE power – power to be allocated to the critical PoE interface,
regardless of whether PoE is enabled for the PoE interface) is lower than the
maximum power of the PoE interface, you will fail to set the priority of the
PoE interface to critical. Otherwise, you can succeed in setting the
priority to critical, and this PoE interface will preempt the power of
other PoE interfaces with a lower priority level. In the latter case, the PoE
interfaces whose power is preempted will be powered off, but their
configurations will remain unchanged. When you change the priority of a PoE
interface from critical to a lower level, the PDs connecting to other PoE
interfaces will have an opportunity of seizing power.
I. Configuration prerequisites
Enable PoE for PoE interfaces.
II. Configuration procedure
Follow these steps to configure PD power
management:
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To do…
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Use the command…
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Remarks
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Enter system view
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system-view
|
—
|
|
Configure the power priority for a PoE
interface
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Configure the power priority for the PoE
interface in PoE interface view
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interface interface-type interface-number
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Use either approach.
By default, the power priority of a PoE
interface is low.
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poe priority { critical | high | low }
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Configure the power priority for the PoE
interface in PoE configuration file view
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poe-profile profile-name [ index ]
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|
poe priority { critical | high | low }
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|
Configure a PD power management priority policy
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poe pd-policy priority
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Optional
By default, no PD power management
priority policy is configured.
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When the PSE power is to be at full load, power is
supplied to a new PD based on the priority policy.
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The power priority of all the PoE interfaces is
based on the same card. That is, power priority of PoE interfaces on different
cards cannot be compared.
1.7 Configuring PoE Monitoring
The PoE monitoring function involves
monitoring of PoE power, PSE and PD.
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Monitoring PoE power means monitoring the
voltage of the PoE power.
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When the current power utilization of the PSE is
above or below the alarm threshold for the first time, the system will send a
Trap message.
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When the PSE starts or stops supplying power to
a PD, the system will send a Trap message, too.
Follow these steps to configure PoE power
monitoring:
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To do…
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Use the command…
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Remarks
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|
Enter system view
|
system-view
|
—
|
|
Configure an AC input under-voltage
threshold for the PoE power
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poe-power input-threshold lower value
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Optional
The default is:
181 for 220 VAC input
90 for 110 VAC input
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|
Configure an AC input over-voltage
threshold for the PoE power
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poe-power input-threshold upper value
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Optional
The default is:
264 for 220 VAC input
132 for 110 VAC input
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|
Configure a DC output under-voltage
threshold for the PoE power
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poe-power output-threshold lower value
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Optional
The default is 45.
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Configure a DC output over-voltage
threshold for the PoE power
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poe-power output-threshold upper value
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Optional
The default is 57.
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Caution:
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The under-voltage threshold should be less than
the over-voltage threshold.
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You are recommended to use the default threshold
when configuring under/over-threshold, unless you have specific needs.
Follow these steps to configure a power
alarm threshold for a PSE:
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To do…
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Use the command…
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Remarks
|
|
Enter system view
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system-view
|
—
|
|
Configure a power alarm threshold for a
PSE
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poe utilization-threshold utilization-threshold-value pse pse-id
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Optional
By default, the power alarm threshold for
a PSE is 80%.
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1.8 Enabling the PSE to Detect Nonstandard
PDs
There are standard PDs and nonstandard PDs.
Usually, the PSE can detect only standard PDs and supply power to them. The PSE
can detect nonstandard PDs and supply power to them only after the PSE is
enabled to detect nonstandard PDs.
Follow these steps to enable the PSE to
detect nonstandard PDs:
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To do…
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Use the command…
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Remarks
|
|
Enter system view
|
system-view
|
—
|
|
Enable the PSE to detect nonstandard PDs
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poe legacy enable pse pse-id
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Optional
By default, the PSE is disabled from
detecting nonstandard PDs.
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1.9 Displaying and Maintaining PoE
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To do…
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Use the command…
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Remarks
|
|
Display the mapping between ID, module,
and slot of all PSEs.
|
display poe device
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Available in any view
|
|
Display the power state and information
of the specified PoE interface
|
display poe interface [ interface-type interface-number ]
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Available in any view
|
|
Display the power information of a PoE
interface(s)
|
display poe interface power [ interface-type interface-number ]
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Available in any view
|
|
Display the power information of the PoE
power and all PSEs
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display poe power-usage
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Available in any view
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Display the information of PSE
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display poe pse [ pse-id ]
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Available in any view
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Display the power state and information
of all PoE interfaces connected with the PSE
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display poe [ pse pse-id ] interface
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Available in any view
|
|
Display the power of all PoE interfaces
connected with the PSE
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display poe [ pse pse-id ] interface power
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Available in any view
|
|
Display information of the PoE power
|
display poe-power
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Available in any view
|
|
Display the state information of the AC
input power
|
display poe-power ac-input state
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Available in any view
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Display the alarm information of the PoE
power
|
display poe-power alarm
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Available in any view
|
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Display the state information of the DC
output power
|
display poe-power dc-output state
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Available in any view
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Display the parameter values of the DC
output power
|
display poe-power dc-output value
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Available in any view
|
|
Display the status information of the PoE
power
|
display poe-power status
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