About configuring PoE

In the default configuration,PoE support is enabled on the ports in a PoE module installed on the switch. The default priority for all ports is low and the default power notification threshold is 80%.

Using the CLI, you can:

  • Disable or re-enable PoE operation on individual PoE ports.

  • Enable support for pre-standard devices.

  • Change PoE priority level on individual PoE ports.

  • Change the threshold for generating a power level notice.

  • Manually allocate the amount of PoE power for a port by usage, value, or class.

  • Allocate PoE power based on the link-partner's capabilities via LLDP.

For a given level, ports are prioritized by port number in ascending order. For example, if ports A1 to A24 have a priority level of critical, port A1 has priority over ports A2 to A24.

If there is not enough power available to provision all active PoE ports at a given priority level, the lowest-numbered port at that level is provisioned first. For chassis switches, the lowest-numbered port at that level starting with module A, then B, C, and so on is provisioned. PoE priorities are invoked only when all active PoE ports cannot be provisioned (supplied with PoE power.)

In chassis switches, you can use one command to set the same priority level on PoE ports in multiple modules. For example, to configure the priority to High for ports c5 to c10, C23 to C24, D1 to D10, and D12, you could use this command:

switch# interface c5-c10,c23-c24,d1-d10,d12 power-over-ethernet high

PoE priority example

PoE priority operation on a PoE module

Port

Priority setting

Configuration command and resulting operation with PDs connected to ports C3 through C24

C3 - C17

Critical
In this example, the following CLI command sets ports C3 to C17 to Critical:
switch# interface c3-c17 power-over-ethernet
    critical
The critical priority class always receives power. If there is not enough power to provision PDs on all ports configured for this class, no power goes to ports configured for high and low priority. If there is enough power to provision PDs on only some of the critical-priority ports, power is allocated to these ports in ascending order, beginning with the lowest-numbered port in the class, which, in this case, is port 3.

C18 - C21

high
In this example, the following CLI command sets ports C19 to C22 to high:
switch# interface c19-c22 power-over-ethernet high
The high priority class receives power only if all PDs on ports with a critical priority setting are receiving power. If there is not enough power to provision PDs on all ports with a high priority, no power goes to ports with a low priority. If there is enough power to provision PDs on only some of the high-priority ports, power is allocated to these ports in ascending order, beginning, in this example, with port 18, until all available power is in use.

C22 - C24

low
In this example, the CLI command sets ports C23 to C24 to low1:
switch# interface c23-c24 power-over-ethernet low
This priority class receives power only if all PDs on ports with high and critical priority settings are receiving power. If there is enough power to provision PDs on only some low- priority ports, power is allocated to the ports in ascending order, beginning with the lowest-numbered port in the class (port 22, in this case), until all available power is in use.

C1 - C2

N/A
In this example, the CLI command disables PoE power on ports C1 to C2:
switch# no interface c1-c2 power-over-ethernet
There is no priority setting for the ports in this example.
1

In the default PoE configuration, the ports are already set to low priority. In this case, the command is not necessary.