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SRX240 Services Gateway Power over Ethernet Overview


This topic includes the following sections:


Power over Ethernet (PoE) provides a device the capability to transmit both data and electric power over a copper Ethernet LAN cable.

The PoE-capable models of the SRX240 Services Gateway (see SRX240 Services Gateway Models) PoE on all Gigabit Ethernet ports. The PoE ports transfer electrical power and data, to remote devices over a standard twisted-pair cable in an Ethernet network. PoE ports allow you to plug in devices that require both network connectivity and electric power, such as wireless LAN access points, and VoIP telephones.

You can configure the services gateway to act as power sourcing equipment for devices connected to the PoE ports.

Table 1 lists the PoE specifications for SRX240 Services Gateway.

Table 1: SRX240 Services Gateway PoE Specifications

Power Management Schemes


Supported standards

  • IEEE 802.3 AF

  • IEEE 802.3 AT (PoE+)

  • Legacy (pre-standards)

Supported ports

PoE is supported on all 16 Gigabit Ethernet ports (0/0 through 0/15; interfaces ge-0/0/0 through ge-0/0/15)

Total PoE power sourcing capacity

150 watts

Per port power limit

30 watts

Note: Default value is 15.4 watts

Power management modes

  • Static: Power allocated for each interface can be configured.

  • Class: Power allocated for interfaces is decided on the basis of class of powered device connected.

PoE Classes and Power Ratings

A powered device is classified on the basis of the maximum power that it draws across all input voltages and operational modes. When class-based power management mode is configured on the services gateway, 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 802.3 AF standard.

Table 2: PoE Classes and Power Ratings


Minimum Power Level Output from PoE Port


15.4 watts


4.0 watts


7.0 watts


15.4 watts


30.0 watts