Configuring Power over Ethernet
Power over Ethernet (PoE) is the implementation of the IEEE 802.3 AF and IEEE 802.3 AT standards that allow both data and electrical power to pass over a copper Ethernet LAN cable. The topics below discuss the overview and configuration details of PoE, and disabling a PoE interface on security devices.
Understanding Power over Ethernet
Power over Ethernet (PoE) is the implementation of the IEEE 802.3 AF and IEEE 802.3 AT standards that allow both data and electrical power to pass over a copper Ethernet LAN cable.
The SRX Series devices support PoE on Ethernet ports. PoE ports transfer electrical power and data to remote devices over standard twisted-pair cable in an Ethernet network. PoE ports allow you to plug in devices that require both network connectivity and electrical power, such as VoIP and IP phones and wireless LAN access points.
You can configure the SRX Series device to act as power sourcing equipment (PSE), supplying power to powered devices that are connected on designated ports.
This topic contains the following sections:
SRX Series Services Gateway PoE Specifications
Table 1 lists the PoE specifications for the SRX210, SRX220, SRX240, SRX320, SRX650, and SRX550 M devices. (Platform support depends on the Junos OS release in your installation.)
Table 1: PoE Specifications for the SRX210, SRX220, SRX240, SRX320, and SRX650 Devices
Specifications | For SRX210 Device | For SRX220 Device | For SRX240 Device | For SRX320 PoE Device | For SRX 550 M device | For SRX650 Device | |
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Supported standards |
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Supported ports | Supported on two Gigabit Ethernet ports and two Fast Ethernet ports (ge-0/0/0, ge-0/0/1, fe-0/0/2, and fe-0/0/3). | Supported on all 8 Gigabit Ethernet ports (ge-0/0/0 to ge-0/0/7). | Supported on all 16 Gigabit Ethernet ports (ge-0/0/0 to ge-0/0/15). | Supported on all 6 Copper (RJ45) Gigabit Ethernet ports (ge-0/0/0 to ge-0/0/5). | Supported on 16GE-POE xPIM card | Supported on the following ports:
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Total PoE power sourcing capacity | 50 W | 120 W | 150 W | 180 W | The 645 watts AC and 645 watts DC power supplies support the following capacities:
| The 645 watts AC and 645 watts DC power supplies support the following capacities:
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Default per port power limit | 15.4 W | 15.4 W | 15.4 W | 30 W | 15.4 W | 15.4 W | |
Maximum per port power limit | 30 W | 30W | 30 W | 30 W | 30 W | 30 W | |
Power management modes |
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PoE Classes and Power Ratings
A powered device is classified based on the maximum power that it draws across all input voltages and operational modes. When class-based power management mode is configured on the SRX Series devices, power is allocated taking into account the maximum power ratings defined for the different classes of devices.
Table 2 lists the classes and their power ratings as specified by the IEEE standards.
Table 2: SRX Series Devices PoE Specifications
Class | Usage | Minimum Power Levels Output from PoE Port |
|---|---|---|
0 | Default | 15.4 W |
1 | Optional | 4.0 W |
2 | Optional | 7.0 W |
3 | Optional | 15.4 W |
4 | Reserved | Class 4 power devices are eligible to receive power up to 30 W according to IEEE standards. |
PoE Options
When configuring PoE, you must enable the PoE interface in order for the port to provide power to a connected, powered device. In addition, you can configure the following PoE features:
Port priority—Sets port priority. When it is not possible to maintain power to all connected ports, lower priority ports are powered off before higher priority ports. When a new device is connected on a higher-priority port, a lower priority port will be powered off automatically if available power is insufficient to power on the higher priority port. (For the ports with the same priority configuration, ports on the left are given higher priority than the ports on the right.)
Maximum available wattage power available to a port—Sets the maximum amount of power that can be supplied to the port. The default wattage per port is 15.4 watts.
PoE power consumption logging—Allows logging of per-port PoE power consumption. The telemetries section must be explicitly specified to enable logging. If left unspecified, telemetries is disabled by default. The default telemetry duration is 1 hour. The default telemetry interval is 5 minutes.
PoE power management mode—Has two modes:
Class—When a powered device is connected to a PoE port, the power allocated to it is equal to the maximum power for the class as defined by the IEEE standards.
Static—When a powered device is connected to a PoE port, the power allocated to it is equal to the maximum power configured for the port.
Reserve power—Reserves the specified amount of power for the gateway in case of a spike in PoE consumption. The default is 0.
See also
Example: Configuring PoE on an Individual Interface
This example shows how to configure PoE on an individual interface.
Requirements
Before you begin:
Configure Ethernet interfaces. See Example: Creating an Ethernet Interface.
Configure PoE on all interfaces. See Example: Configuring PoE on All Interfaces.
Overview
This example shows how to configure PoE on the ge-0/0/0 interface. In this example, you set the power port priority to high and the maximum power available to a port to 15.4 watts. Then you enable the PoE power consumption logging with the default telemetries settings, and you set the PoE management mode to static. Finally, you set the reserved power to 15 watts in case of a spike in PoE consumption.
Configuration
CLI Quick Configuration
To quickly configure this example, copy the following command, paste it into a text file, remove any line breaks, change any details necessary to match your network configuration, copy and paste the command into the CLI at the [edit] hierarchy level, and then enter commit from configuration mode.
Step-by-Step Procedure
The following example requires you to navigate various levels in the configuration hierarchy. For instructions on how to do that, see the Junos OS CLI User Guide.
To configure PoE:
- Enable PoE.[edit]user@host# edit poe interface ge-0/0/0
- Set the power port priority.[edit poe interface ge-0/0/0]user@host# set priority high
- Set the maximum PoE wattage available for a port.[edit poe interface ge-0/0/0]user@host# set maximum power 15.4
- Enable logging of PoE power consumption.[edit poe interface ge-0/0/0]user@host# set telemetries
- Set the PoE management mode.[edit]user@host# set poe management static
- Reserve power wattage in case of a spike in PoE consumption.[edit]user@host# set poe guard-band 15
Results
From configuration mode, confirm your configuration by entering the show poe interface ge-0/0/0 command. If the output does not display the intended configuration, repeat the configuration instructions in this example to correct it.
If you are done configuring the device, enter commit from configuration mode.
Verification
Confirm that the configuration is working properly.
Verifying the Status of PoE Interfaces
Purpose
Verify that the PoE interfaces on the device are enabled and set to the desired priority settings. (The device used in this example is the SRX240 or SRX340 Services Gateway, depending on the Junos OS release in the installation.)
Action
From operational mode, enter the show poe interface ge-0/0/1 command.
user@host> show poe interface ge-0/0/1PoE interface status: PoE interface : ge-0/0/1 Administrative status : Enabled Operational status : Powered-up Power limit on the interface : 15.4 W Priority : High Power consumed : 6.6 W Class of power device : 0
The show poe interface ge-0/0/1 command lists PoE interfaces configured on the SRX340 device, with their status, priority, power consumption, and class.
Verifying the Telemetry Data (History) for the Specified Interface
Purpose
Verify the PoE interface's power consumption over a specified period.
Action
From operational mode, enter the show poe telemetries interface command.
For all records:
user@host> show poe telemetries interface ge-0/0/1
allSl No Timestamp Power Voltage 1 Fri Jan 04 11:41:15 2009 5.1 W 47.3 V 2 Fri Jan 04 11:40:15 2009 5.1 W 47.3 V 3 Fri Jan 04 11:39:15 2009 5.1 W 47.3 V 4 Fri Jan 04 11:38:15 2009 0.0 W 0.0 V 5 Fri Jan 04 11:37:15 2009 0.0 W 0.0 V 6 Fri Jan 04 11:36:15 2009 6.6 W 47.2 V 7 Fri Jan 04 11:35:15 2009 6.6 W 47.2 V
For a specific number of records:
user@host> show poe telemetries interface ge-0/0/1
5Sl No Timestamp Power Voltage 1 Fri Jan 04 11:31:15 2009 6.6 W 47.2 V 2 Fri Jan 04 11:30:15 2009 6.6 W 47.2 V 3 Fri Jan 04 11:29:15 2009 6.6 W 47.2 V 4 Fri Jan 04 11:28:15 2009 6.6 W 47.2 V 5 Fri Jan 04 11:27:15 2009 6.6 W 47.2 V
The telemetry status displays the power consumption history for the specified interface, provided telemetry has been configured for that interface.
Verifying PoE Global Parameters
Purpose
Verify global parameters such as guard band, power limit, and power consumption.
Action
From operational mode, enter the show poe controller command.
user@host> show poe controllerController Maximum Power Guard band Management index power consumption 0 150.0 W 0.0 W 0 W Static
The show poe controller command lists the global parameters configured on the SRX Series device such as controller index, maximum power, power consumption, guard band, and management mode along with their status.
Example: Configuring PoE on All Interfaces
This example shows how to configure PoE on all interfaces.
Requirements
Before you begin, configure Ethernet interfaces. See Example: Creating an Ethernet Interface.
Overview
This example shows how to configure PoE on all interfaces on a device. In this example, you set the power port priority to low and the maximum power available to a port to 15.4 watts. Then you enable the PoE power consumption logging with the default telemetries settings, and you set the PoE management mode to static. Finally, you set the reserved power consumption to 15 watts in case of a spike in PoE consumption.
Configuration
CLI Quick Configuration
To quickly configure this example, copy the following command, paste it into a text file, remove any line breaks, change any details necessary to match your network configuration, copy and paste the command into the CLI at the [edit] hierarchy level, and then enter commit from configuration mode.
Step-by-Step Procedure
The following example requires you to navigate various levels in the configuration hierarchy. For instructions on how to do that, see the Junos OS CLI User Guide.
To configure PoE on all interfaces:
- Enable PoE.[edit]user@host# edit poe interface all
- Set the power port priority.[edit poe interface all]user@host# set priority low
- Set the maximum PoE wattage available for a port.[edit poe interface all]user@host# set maximum-power 15.4
- Enable logging of PoE power consumption.[edit poe interface all]user@host# set telemetries
- Set the PoE management mode.[edit]user@host# set poe management static
- Reserve power wattage in case of a spike in PoE consumption.[edit]user@host# set poe guard-band 15
Results
From configuration mode, confirm your configuration by entering the show poe interface all command. If the output does not display the intended configuration, repeat the configuration instructions in this example to correct it.
If you are done configuring the device, enter commit from configuration mode.
Verification
Confirm that the configuration is working properly.
Verifying the Status of PoE Interfaces
Purpose
Verify that the PoE interfaces on the device are enabled and set to the desired priority settings. (The device used here is the SRX340 Services Gateway.)
Action
From operational mode, enter the show poe interface all command.
Interface Admin status Oper status Max power Priority Power consumption Class ge-0/0/0 Enabled Searching 15.4W Low 0.0W 0 ge-0/0/1 Enabled Powered-up 15.4W High 6.6W 0 ge-0/0/2 Disabled Disabled 15.4W Low 0.0W 0 ge-0/0/3 Disabled Disabled 15.4W Low 0.0W 0
The show poe interface all command lists PoE interfaces configured on the SRX320 PoE device, including information on status, priority, power consumption, and class. This output shows that the device has four PoE interfaces of which two are enabled with default values. One port has a device connected that is drawing power within expected limits.
See also
Example: Disabling a PoE Interface
This example shows how to disable PoE on all interfaces or on a specific interface.
Requirements
Before you begin:
Configure PoE on all interfaces. See Example: Configuring PoE on All Interfaces.
Configure PoE on an individual interface. See Example: Configuring PoE on an Individual Interface.
Overview
In this example, you disable PoE on all interfaces and on a specific interface, which in this case is ge-0/0/0.
Configuration
Step-by-Step Procedure
To disable PoE on interfaces:
- Disable PoE on all interfaces.[edit]user@host# set poe interface all disable
- Disable PoE on a specific interface.[edit]user@host# set poe interface ge-0/0/0 disable
- If you are done configuring the device, commit the configuration.[edit]user@host# commit
Verification
To verify the configuration is working properly, enter the show poe interface command.