PoE Features

Fast PoE and Perpetual PoE

  • Fast PoE restores power to endpoint devices quickly after a power failure or reset, without waiting for IOS-XE to boot up.

  • Perpetual PoE preserves power to powered devices (PDs) during IOS-XE reboot, ensuring that devices remain powered and connected.

Fast PoE and Perpetual PoE operation

PoE support for Cisco Catalyst IE9300 Rugged Series Switches includes Fast PoE, which restores power during system boot, and Perpetual PoE, which preserves power during system boot.

Fast PoE operation:

  1. When poe-ha is enabled on a port, the switch provides power to connected endpoint devices immediately after a power failure or reset, before IOS-XE forwarding starts.

  2. The system loads and validates the power sourcing equipment (PSE) firmware before initiating Fast PoE connections.

  3. The system verifies that adequate power budget is available for all Fast PoE reconnections. If the budget is insufficient, Fast PoE ports are reconnected starting from the lower interface number until the budget is exhausted.

  4. Fast PoE can be used after both reset and power cycle.

Perpetual PoE operation:

  • Perpetual PoE ensures that PDs do not lose power when IOS-XE is rebooted by not resetting the PSE controllers, so their loads stay connected.

  • The system securely stores the firmware information after validation and can detect if the firmware has not changed since the last validation after a reset.

  • Perpetual PoE is sometimes referred to as Persistent PoE.

Restrictions for Fast PoE and Perpetual PoE

The following restrictions apply to Fast PoE and Perpetual PoE:

  • You must configure Fast PoE or Perpetual PoE before physically connecting any endpoint. Alternatively, you can do a manual shut/no-shut of the ports drawing power.

  • In case of an MCU firmware upgrade, power to the ports is interrupted and ports are backed up immediately after the upgrade.

  • The Cree Lighting PD may flap at regular intervals if not configured with IP assigned from the DHCP server.

  • If the PD does not support LLDP, you can configure with either static or 2-event to receive required power according to the PD specification.

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Configure Perpetual PoE and Fast PoE

Perform this task to configure Fast PoE and Perpetual PoE.

Procedure

  Command or Action Purpose

Step 1

Use the enable command to enter privileged EXEC mode.

Example:

Switch#enable

Enter your password if prompted.

Step 2

Use the configure terminal command to enter global configuration mode.

Example:

Switch#configure terminal

Step 3

Use the interface interface-id command to specify the physical port to be configured and enter interface configuration mode.

Example:

Switch(config)# interface gigabitethernet2/0/1

Step 4

Use the power inline port perpetual-poe-ha command to configure Perpetual PoE on the interface.

Example:

Switch(config-if)#power inline port perpetual-poe-ha

This ensures the powered device remains powered during a switch reload.

Step 5

Use the power inline port poe-ha command to configure Fast PoE on the interface.

Example:

Switch(config-if)# power inline port poe-ha

This allows the powered device to power on quickly after a power cycle without waiting for IOS to boot.

Step 6

Use the end command to exit interface configuration mode and return to privileged EXEC mode.

Example:

Switch(config-if)# end

Note

 

  • Configure Perpetual PoE before Fast PoE.

  • If a powered device is connected after configuring Fast PoE, shut the port, and then use the no shut command to apply the changes.

Example: Configuring Fast PoE and Perpetual PoE

This example shows how you can configure perpetual PoE on a switch:

Device> enable
Device# configure terminal
Device(config)# interface gigabitethernet2/0/1 
Device(config-if)# power inline port perpetual-poe-ha
Device(config-if)# end

Feature History: PoE

This table IE-9320-16P8U4X-E captures release-related information for features explained in this module. Unless specified, each feature continues to be supported in later releases.

Release

Feature

Feature Information

Cisco IOS XE Dublin 17.12.x

Power over Ethernet (PoE)

PoE delivers DC power to devices over copper Ethenet cabling and removes the need for separate power supplies and outlets.

You can configure PoE on the following Cisco Catalyst IE9300 Rugged Series Switch models:

  • IE-9320-24P4X-A and IE-9320-24P4X-E

  • IE-9320-16P8U4X-A and IE-9320-16P8U4X-E

  • IE-9320-24P4S-A and IE-9320-24P4S-E