Summary

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Sub-menu:

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/interface ethernet poe

This page describes how PoE-Out (Power over Ethernet) feature can be used on MikroTik devices with at least one PoE-Out interface. MikroTik uses RJ45 mode B pinout for power distribution, where the PoE is passed trough pins 4,5 (+) and 7,8 (-). If a device supports powering other devices using PoE-out, then it is recommended to use at least 18V as the input voltage, except for devices that support multiple output voltages (e.g. CRS112-8P-4S-IN, CRS328-24P-4S+RM, CRS354-48P-4S+2Q+RM).

MikroTik supported PoE-Out standards

MikroTik devices can support some or all of the following PoE standards:

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PoE-Out Configuration

PoE Configuration is supported on all MikroTik devices with PoE-Out interfaces, the configurations can be edited from the RouterOS and SwOS interfaces.

RouterOS

Usage

RouterOS provides an option to configure PoE-Out over Winbox, Webfig, and CLI, basic commands using the CLI are

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Port Settings

PoE-Out can be configured under the menu. Each port can be controlled independently.

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Power-cycle settings

RouterOS provides a possibility to monitor PD using a ping, and power-cycle a PoE-Out port when the host does not respond. power-cycle-ping feature can be enabled under /interface ethernet poe menu.

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If power-cycle is enabled, /interface ethernet poe monitor will show the actual status of the host and time when power cycle will be performed [1]

SwOS

SwOS interface provides basic PoE-Out configuration options:

• PoE Out - Change between PoE-out modes (auto/on/off)
• PoE Priority - Change the Priority of port (0...8)
• Voltage Level - Change between two voltage outputs on PoE-Out ports (auto/low/high)

PoE-Out Monitoring

RouterOS

MikroTik devices with PoE-Out controller (not injector) provides port monitoring option. /interface ethernet poe monitor [find]

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SNMP

It is possible to monitor PoE-Out values using SNMP protocol, this requires enabled SNMP on PSE. SNMP Wiki

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All PoE-Out configuration and monitoring is located on one page, under PoE tab https://<IP>/index.html#poe:

PoE-Out notifications

PoE-Out LEDs

Models with dependant voltage output

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• CRS112-8P-4S-IN - All PoE LEDs flashing: wrong voltage PSU plugged into one of the ports.
• netPower 16P - All PoE LEDs flashing: wrong voltage PSU plugged into one of the ports.
• CRS328-24P-4S+RM - indicates an exceeded overall max PoE output limit. Port PoE-Out priorities will work in 3 independent sections (8 ports each) and overload will happen in any section that breaches 150W consumption.

PoE-Out Logs

By default PoE-Out, event logging is enabled and uses "warning" and "info" topics to notify the user about PoE-Out state changes. Log entries will be added to each PoE-Out state change. Important logs will be added with a "warning" topic, informative logs will be added with the "info" topic.

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PoE-Out Warnings in GUI/CLI

To notify a user about important PoE-Out related problems, messages will be shown in Winbox / WebFig and CLI interface fields:

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WebFig and Winbox will notify user under interfaces:

How it works

PoE-Out Modes

auto-on mode

If auto-on is selected on PoE-Out interface, then port operates in this strict order:

• PSE with low voltage checks for resistance on the connected port. If the detected resistance range is between (3kΩ to 26.5kΩ) power is turned on;
• When power is applied, the PSE continuously checks if the overload limit is not reached or short circuit detected
• If the cable is unplugged, the port returns in detection state and will remain off until suitable PD is detected

forced-on mode

If forced-on is selected then port operates in this strict order:

• PSE disables resistance check on the port, and apply power on pins 4,5 (+) and 7,8 (-), even if no cable is attached
• When power is applied, PSE still continuously checks if an overload or short circuit is not detected
• After the cable is unplugged, the power still remains enabled on the port.

off mode

If off mode is used, PoE-Out on the port will be turned off, no detection will take place, and the interface will behave like a simple Ethernet port.

PoE-Out limitations

It is important to check PoE-Out specification to find out hardware limitations because it can differ between models

PoE-Out port limitation

PoE-Out ports are limited with max amp values which are supported in particular voltage, usually max current will differ for low voltage devices (up to 30 V), and for high voltage devices (31 to 57 V).

PoE-Out total limitation

PSE has also a total PoE-Out current limitation which can't be exceeded, even if the individual port limit allows it.

PoE Out polarity

All MikroTik PSE uses the same PoE-Out pin polarity Mode B4,5 (+) and 7,8 (-), however other vendors can use opposite or Mode A pinout on PD. Reverse polarity would require using a crossover cable but Mode A PD would require Mode B to Mode A converter.

Safety

PSE has the following safety features:

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Model-specific features

PSE with independent 8-port sections (CRS112-8P-4S-IN, CRS328-24P-4S+RM, netPower 16P, CRS354-48P-4S+2Q+RM) allows PoE-Out to work independently from the RouterOS, this means that you can reboot/upgrade your RouterOS and the PD will not be rebooted.

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PoE Out examples

RouterOS allows us to define priorities on PoE-Out ports, so if your installation is going overpower budget, the PSE will disable less important PD with the lowest priority.

The priority of 0 is the highest priority, 99 - lowest

Setting up priority

Example of how to set priorities from CLI:

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What will happen when power budget will go over total PoE-Out limit - first if the overload is detected, ether5 will be turned off (lowest priority), then recheck is done and if the still total limit overload is detected next port in priority will be turned off, in this example, ether3 will be turned off. Both of these ports will be reached every few seconds to check if it is possible to turn PoE-Out on for these ports. Power up will happen in reverse order as the power was cut.

Same priority

if all, or some ports will have the same poe-priority, then port with the lowest port number will have higher priority

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In this example, if the total PoE-Out limit is reached ether5 will be turned off first, then ether4 then ether3 as all of these ports have same poe priority.

Monitoring PoE-Out

PoE-Out ports can be monitored using a command /interface ethernet poe monitor <interface>

Power-cycle ping

Monitor connected PD with power-cycle-ping feature:

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In this example, PD attached to ether1 will be continuously monitored using a power-cycle-ping feature, which will send ICMP ping requests and wait for a reply. If PD with IP address 192.168.88.10 will not respond for more than 30s, the PoE-Out port will be switched off for 5s.

Troubleshooting

In cases where a PD does not power-up or reboots unexpectedly when powered from your PSE, it's suggested to the first check:

• PD supported input voltage - PSE output voltage must be in the range supported by the PD. Otherwise, the PD is incompatible with the PSE, and will not be able to power-up. Check the PD datasheet.
• PD supported input PoE-in standard - Some PDs do not support af/at standard even if it has PoE-in support up to 57 V, check PD datasheet.
• PD is rebooted from PSE
  • Check if PD does not exceed PoE-Out port limit and Total-PoE-Out port limit of the PSE, check PSE datasheet.
  • Check if the Voltage limit does not drop bellow supported (Can be caused by voltage drop on the wires).
  • Check if you are using a proper power supply, the output power of PSU should be calculated from:

    (MAX power consumption of PSE) + (MAX power consumption of all PD) + 10%)

  • Check if you are using good quality ethernet cables, it's important especially in cases if PoE is used.
• Check RouterOS version - it's possible, that some PoE related features will be updated with RouterOS, make sure that you are running the latest RouterOS version.
• PD Does not power up
  • There can be cases where a PD does not power up, even though it supports passive PoE, and does not consume more power than the specified PSE port limit. This can be caused by inrush current triggering overcurrent protection on the PSE. Make sure that PD specification supports powering from PSE (not only from passive power injector)
  • Polarity - Devices with opposite or different pinouts can be unable to powerup from all PSE. Check the PD datasheet.
  • Incompatible resistance - PD resistance should have ranged from 3kΩ to 26.5kΩ (For Passive-PoE) and from 23.75kΩ to 26.25kΩ on af/at.

Legacy

PoE-Out Controller upgrade

PoE-Out devices which are running RouterOS 5.x can also hold old PoE-Out controller firmware, upgrade to RouterOS 6.x will automatically update the PoE-Out firmware. Changes between 1.x and 2.x PoE-Out controller firmware will result in higher Max-port limits (0.5A to 1A) in case if it's supported by the hardware, also will provide some additional data which can be monitored, and allow to use PoE-Out priorities.

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