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Power over Ethernet (PoE) on ACX Series Routers

 

You can configure the ACX2000 Universal Metro Routers to enable the Power over Ethernet (PoE) ports to transfer both data and electrical power over a copper Ethernet LAN cable. This topic provides an overview of PoE support on ACX2000 routers and also provides information on how to configure, disable, and troubleshoot the PoE interface configured on the ACX2000 device.

Understanding PoE on ACX Series Universal Metro Routers

Power over Ethernet (PoE) is the implementation of the IEEE 802.3af and IEEE 802.3at standards that allows both data and electrical power to pass over a copper Ethernet LAN cable.

Juniper Networks provides PoE on ACX2000 Universal Metro Routers that allows power delivery up to 65 W per PoE port. PoE ports transfer electrical power and data to remote devices over standard twisted-pair cables in an Ethernet network. Using the PoE ports, you can plug in devices that require both network connectivity and electrical power, such as voice over IP (VoIP) and wireless LAN access points.

You can configure the ACX2000 Universal Metro Router to act as a power sourcing equipment (PSE), supplying power to powered devices that are connected on designated ports.

This topic contains the following sections: :

ACX2000 PoE Specifications

Table 1 lists the PoE specifications for the ACX2000 routers.

Table 1: PoE Specifications for the ACX2000 Routers

Specifications

For ACX2000 Universal Metro Routers

Supported standards

  • IEEE 802.3 AF

  • IEEE 802.3 AT (PoE+)

  • Legacy (pre-standards)

Supported ports

Supported on only two Gigabit Ethernet ports (ge-0/1/3 and ge-0/1/7).

Total PoE power sourcing capacity

130 W

Default per port power limit

32 W

Maximum per port power limit

65 W

Power management modes

  • class—Power allocated for each interface can be configured.

  • static—Power allocated for interfaces is based on the class of powered device connected.

  • high-power—Power allocated for interfaces up to 65 W per port.

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 ACX2000 routers, 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: ACX2000 Universal Metro Router 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 the IEEE standards.

PoE Options

For ACX2000 Universal Metro Routers that support PoE ports, the factory default configuration enables PoE on the PoE-capable ports, with default settings in effect. You might not have to do any additional configuration if the default settings work for you. Table 3 shows the PoE configuration options and their default settings for the PoE controller and for the PoE interfaces.

Table 3: PoE Configuration Options and Default Settings

Option

Default

Description

PoE Controller Options

guard-band

0 W

Reserves up to 19 W power from the PoE power budget to be used in the case of a spike in PoE power consumption.

management

static

Sets the PoE power management mode for the router. The power management mode determines how power to a PoE interface is allocated:

  • class—Power allocated for each interface can be configured.

  • static—Power allocated for interfaces is based on the class of powered device connected.

  • high-power—Power allocated for interfaces up to 65 W per port.

Interface Options

disable (Power over Ethernet)

Not included in default configuration

When included in the configuration, disables PoE on the interface. The interface maintains network connectivity but no longer supplies power to a connected powered device. Power is not allocated to the interface.

priority (Power over Ethernet)

low

Sets an interface’s power priority to either low or high. If power is insufficient for all PoE interfaces, the PoE power to low-priority interfaces is shut down before power to high-priority interfaces is shut down. Among interfaces that have the same assigned priority, the power priority is determined by port number, with lower-numbered ports having higher priority.

telemetries

Not included in default configuration

When included in the configuration, enables the logging of power consumption records on an interface. Logging occurs every 5 minutes for 1 hour unless you specify a different value for interval (Power over Ethernet) or duration.

Example: Configuring PoE on ACX2000 Routers

Power over Ethernet (PoE) ports supply electric power over the same ports that are used to connect network devices. These ports allow you to plug in devices that need both network connectivity and electric power, such as voice over IP (VoIP) phones, wireless access points, and IP cameras.

This example shows how to configure PoE to deliver power up to 65 W on ACX2000 interfaces:

Requirements

This example uses the following software and hardware components:

  • Junos OS Release 12.2 or later for ACX Series routers

  • An ACX2000 router that supports PoE

Before you configure PoE, be sure you have:

Overview

This example consists of a router that has eight ports. Only two ports—ge-0/1/3 and ge-0/1/7—support PoE, which means they provide both network connectivity and electric power for powered devices such as VoIP telephones, wireless access points, and IP security cameras that require power up to 65 W. The remaining six ports provide only network connectivity. You use the standard ports to connect devices that have their own power sources, such as desktop and laptop computers, printers, and servers.

Table 4 details the topology used in this configuration example.

Table 4: Components of the PoE Configuration

PropertySettings

Hardware

ACX2000 router with 8 Gigabit Ethernet ports: Two PoE interfaces (ge-0/1/3 and ge-0/1/7) and 6 non-PoE interfaces (ge-0/1/0, ge-0/1/1, ge-0/1/2, ge-0/1/4, ge-0/1/5, ge-0/1/6).

VLAN name

default

Connection to a wireless access point (requires PoE)

ge-0/1/7

Power port priority

high

Maximum power available to PoE port

65 W

PoE management mode

high-power

Direct connections to desktop PCs, file servers, integrated printer/fax/copier machines (no PoE required)

ge-0/1/0 through ge-0/1/2

Unused ports (for future expansion)

ge-0/1/4 through ge-0/1/6

Configuration

To configure PoE on an ACX2000 router:

CLI Quick Configuration

To quickly configure this example, copy the following commands, paste them into a text file, remove any line breaks, change any details necessary to match your network configuration, and then copy and paste the commands into the CLI at the [edit] hierarchy level.

set poe management high-power guard-band 19
set poe interface ge-0/1/3 priority high maximum-power 65 telemetries

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 Using the CLI Editor in Configuration Mode in the CLI User Guide.

To configure PoE:

  1. Set the PoE management mode to high-power.
    Note
    • Set the PoE management mode to high-power only when the power requirement is more than 32 W and up to 65 W. If the power requirement is less than or equal to 32 W, then you do not need to set the PoE management mode to high-power.

    • The default management mode is static. In this mode, the power sourcing equipment can deliver power up to 32 W.

  2. Reserve power wattage in case of a spike in PoE consumption.
  3. Enable PoE.
  4. Set the power port priority.
  5. Set the maximum PoE power for a port.
    Note

    Set the maximum PoE power for a port only when the power requirement is more than 32 W and up to 65 W. If the power requirement is less than or equal to 32 W, then you do not need to configure the maximum PoE power.

  6. Enable the logging of PoE power consumption.

Results

In configuration mode, confirm your configuration by entering the show poe interface ge-0/1/3 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 in configuration mode.

Verification

To confirm that the configuration is working properly, perform these tasks:

Verifying the Status of PoE Interfaces

Purpose

Verify that the PoE interfaces are enabled and set to the desired priority settings.

Action

In operational mode, enter the show poe interface ge-0/1/3 command.

user@host> show poe interface ge-0/1/3

Meaning

The show poe interface ge-0/1/3 command lists PoE interfaces configured on the ACX2000 router, 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

In operational mode, enter the show poe telemetries interface command.

For all records:

user@host> show poe telemetries interface ge-0/1/3 all

For a specific number of records:

user@host> show poe telemetries interface ge-0/1/3 2

Meaning

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

In operational mode, enter the show poe controller command.

user@host> show poe controller

Meaning

The show poe controller command lists the global parameters configured on the router.

Example: Disabling a PoE Interface on ACX2000 Routers

This example shows how to disable PoE on all interfaces or on a specific interface.

Requirements

Before you begin:

Overview

In this example, you disable PoE on all interfaces and on a specific interface, which in this case is ge-0/1/3.

Configuration

Step-by-Step Procedure

  • Disable PoE on all interfaces.

  • Disable PoE on a specific interface.

Verification

To verify the configuration is working properly, enter the show poe interface command.

user@host> show poe interface
user@host> show poe interface ge-0/1/3

Troubleshooting PoE Interfaces on ACX2000 Universal Metro Routers

Problem

Description: A Power over Ethernet (PoE) interface is not supplying power to the powered device.

Solution

Check for the items shown in Table 5.

Table 5: Troubleshooting a PoE Interface

Items to CheckExplanation

Is interface PoE enabled?

Only interfaces ge-0/1/3 and ge-0/1/7 can function as PoE ports.

Has PoE capability been disabled for that interface?

Use the show poe interface command to check PoE interface status.

Is the cable properly seated in the port socket?

Check the hardware.

Does the powered device require more power than is available on the interface?

Use the show poe interface command to check the maximum power provided by the interface.

If the telemetries option has been enabled for the interface, check the history of power consumption.

Use the show poe telemetries command to display the history of power consumption.