RouterOS PoE Monitoring

What it is

PoE monitoring shows what each PoE port is doing, and how much electrical power the device behind it is using.

You use it to confirm that a device receives power, to find faults such as a short circuit, and to see how close the switch is to its limit. It also helps you decide whether a device should have a higher priority.

Monitoring is a read only view. The settings you change live in the PoE configuration, covered on the earlier pages.

How it works

The monitor command reports live values for a port.

The monitor command

Use monitor with the port name.

/interface ethernet poe monitor ether2
/interface ethernet poe monitor [find] once

The first line follows one port and updates the display. The second prints all ports one time. The output includes the status and the electrical values.

Values you see

The main fields are these.

Voltage times current gives power, so the three electrical values agree with each other. A device that draws almost nothing may be off, asleep or disconnected.

Status values

The status tells you the state in plain words.

A port set to off shows that it is disabled. Other values exist, and the exact list depends on the model and version.

Reading faults

Common patterns point to common causes.

• waiting-for-load for a device that should work: the cable is not connected, the device does not support the mode, or it is passive and needs forced-on.
• short-circuit: a damaged cable, a bad connector or a faulty device. Replace the cable first.
• overload: the device needs more power than the port offers. Check the standard of the port and the demand of the device.
• Low voltage on the device side: a long cable or thin conductors lose voltage.

Budget and logs

Watch the total as well as each port.

If several ports show high power use, the switch may be close to its budget. Ports with a worse priority can be cut, and the router writes events to the log.

/log print where message~"poe"

Reading the log after an outage shows whether power loss was caused by a budget problem or a fault on one port.

Power cycle ping

Some models can restart a frozen device automatically.

The switch pings the device at an address you give. If the ping fails for a set time, the switch turns the port off and on, which restarts the device.

/interface ethernet poe set ether2 power-cycle-ping-enabled=yes power-cycle-ping-address=192.168.88.20

This helps with remote access points and cameras that sometimes freeze. Use it only when the address belongs to that device, because a wrong address would restart a healthy device again and again.

Checking regularly

Look at the readings when you install a device and again later.

A reading taken at install time becomes your baseline. If the power rises sharply later, a fault is developing, such as a damaged cable or a failing device.