/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 over spare pairs, 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. CRS328-24P-4S+, CRS112-8P-4S).
MikroTik supported PoE-Out standards
MikroTik devices can support some or all of the following PoE standards:
- Passive PoE-Out up to 30 V - PoE standard, which does not require negotiation between PSE (Power Sourcing Equipment) and PD (Powered Device). For PoE-out uses the same voltage as supplied to the PSE (Power Sourcing Equipment). PoE-Out Standard for devices which supports input voltage up to 30 V. PD resistance on spare pairs should have range from 3kΩ to 26.5kΩ. (e.g. hEX PoE lite, RB3011UiAS-RM, RB2011iL-IN.)
- Passive PoE-Out up to 57 V - Works same as low voltage (up to 30 V) PoE-Out, but is also capable to deliver high voltage over PoE ports. The output voltage depends from the power source connected to PSE. Can power up af/at compatible devices, which accepts power over 4,5 (+) and 7,8 (-), and does not require PoE negotiation. PD resistance on spare pairs should have range from 3kΩ to 26.5kΩ. (e.g. cAP ac, hAP ac, wsAP ac lite.)
- IEEE Standards 802.3af/at - Also called PoE Type 1/PoE+ Type 2, are PoE standards Defined by the IEEE. The aim of these standards is to reduce incompatibility between vendors. MikroTik PSE with af/at support is capable of powering both a Type 1 and a Type 2 PD. Valid PD should have PoE-In resistance from 23.75kΩ to 26.25kΩ. MikroTik devices which support af/at standard can also switch to Passive PoE-Out mode. (e.g. hEX PoE, CRS112-8P-4S-IN, CRS328-24P-4S+RM.)
Each PoE-Out implementation supports overload and short-circuit detection.
PoE Configuration is supported on all MikroTik devices with PoE-Out interfaces, the configurations can be edited from the RouterOS and SwOS interfaces.
RouterOS provides an option to configure PoE-Out over Winbox, Webfig and CLI, basic commands using the CLI are
|print ()||Prints PoE-Out related settings.|
|export ()||export is displayed under
|monitor (string| interface)||Shows poe-out-status of a specified port, or all ports with
|power-cycle (time:0..1m |; Default: 5s)||Disables PoE-Out power for a specified period of time.|
Some MikroTik PoE-Out devices support global PoE setting which can be configured under
/interface ethernet poe settings menu.
Global setting ether1-poe-in-long-cable feature disables strict input/output current monitoring (short detection) to allow the use of PoE-Out with long ethernet cables.
|ether1-poe-in-long-cable (yes | no)||Setting to yes will disable short detection on all poe-out ports to enable the use of longer ethernet cables. This is potentially dangerous settings and should be used with caution|
PoE-Out can be configured under
/interface ethernet poe menu. Each port can be controlled independently.
|name ()||Name of an interface|
|poe-out (auto-on | forced-on | off; Default: auto-on)||Specifies PoE-Out state
|poe-priority (integer:0..99 | any; Default: 10)||poe-priority specifies the importance of PoE-Out ports, in cases when a total PoE-Out limit is reached, interface with the lowest port priority will be powered off first.
Highest priority is 0, lowest priority is 99. If there are 2 or more ports with the same priority then port with the smallest port number will have a higher priority. For example, if ether2 and ether3 have the same priority and over-current is detected then PoE-Out on ether3 will be turned off.Every 6 seconds ports will be checked for a possibility to provide PoE-Out if it was turned off due to port priority.
|poe-voltage (auto | low | high; Default: auto)||Feature which allows to manually switch between two voltage outputs on PoE-Out ports. Will take effect only on PSE with switchable voltage modes (CRS112-8P-4S-IN, CRS328-24P-4S+RM).|
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.
|power-cycle-ping-enabled (yes | no; Default: no)||Enables ping watchdog, power-cycles port if a host does not respond to layer3 (ICMP) or layer2 (ARP-Ping) packets.|
|power-cycle-ping-address (IPv4 | IPv6 | MAC; Default: )||An address which will be monitored|
|power-cycle-ping-timeout (time:0..1h |; Default: 5s)||If the host does not respond for more than <timeout> period of time, then PoE-Out port is switched off for 5s.|
|power-cycle-interval (time| any; Default: )||Disables PoE-Out power for 5s between specified interval. Not related with power-cycle-ping feature.|
If power-cycle is enabled,
/interface ethernet poe monitor will show actual status of the host and time when power cycle will be performed 
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)
MikroTik devices with PoE-Out controller (not injector) provides port monitoring option.
/interface ethernet poe monitor [find]
|name ()||Name of an interface|
|poe-out ()||Shows PoE-Out settings|
|poe-out-status ()||Shows current PoE-Out status on port
Delivered voltage at PD is too low for normal powering;
PD uses second power source which has a higher voltage than PSE, so all current is taken from second DC source, not PSE PoE-Out port;
|poe-out-voltage ()||Displays PoE Voltage which is applied to the PD.|
|poe-out-current ()||Displays port current (mA) which is drawn by the PD.|
|poe-out-power ()||Displays PD power consumption|
power-cycle-ping feature is used,
/interface ethernet poe monitor [find] will show additional fields:
power-cycle-host-alive: <YES/NO> (Shows if monitored host is reachable) power-cycle-after:<TIME> (Shows time, after which the port will be power-cycled)
It is possible to monitor PoE-Out values using SNMP protocol, this requires enabled SNMP on PSE. SNMP Wiki
SNMP OID tables:
- 126.96.36.199.4.1.149188.8.131.52.1.1.1 - interface id
- 184.108.40.206.4.1.149220.127.116.11.1.1.2 - interface names
- 18.104.22.168.4.1.14922.214.171.124.1.1.4 - voltage in dV (decivolt)
- 126.96.36.199.4.1.149188.8.131.52.1.1.5 - current in mA
- 184.108.40.206.4.1.149220.127.116.11.1.1.6 - power usage in dW (deviwatt)
SNMP values can be requested also from the RouterOS, for example,
snmp-walk will print current mA from all available PoE-Out ports:
/tool snmp-walk address=10.155.149.252 oid=18.104.22.168.4.1.14922.214.171.124.1.1.5
To get very specific OID value, use
snmp-get tool (displays current mA on ether3 interface):
tool snmp-get address=10.155.149.252 oid=126.96.36.199.4.1.149188.8.131.52.184.108.40.206
A PoE-Out controller will enable certain monitoring features also from SwOS, such as PoE-Out Status, PoE-Out Current, PoE-Out Voltage and PoE-Out Power usage.
All PoE-Out configuration and monitoring is located on one page, under PoE tab
Models with dependant voltage output
PoE-Out LED behaviour can differ between models, but most of them will indicate PoE-Out state on one additional LED. Devices with one voltage output will light:
- Red colour LED - PoE-Out port state is powered-on (auto or forced-on mode).
- Blinking Red colour LED - PoE-Out port state is short-circuit
Models with selectable voltage output
Models with multiple voltage options can indicate additional information:
- Green colour triangle LED - PoE-Out port state is powered-on (auto or forced-on mode), PD uses low voltage.
- Red colour triangle LED - PoE-Out port state is powered-on (auto or forced-on mode), PD uses high voltage (af/at or passive).
- Blinking Green colour triangle LED - PoE-Out port state is short-circuit or overload
- Blinking Red colour triangle LED - PoE-Out port state is short-circuit or overload
Model-specific LED behaviour
- CRS112-8P-4S - All PoE LEDs flashing: wrong voltage PSU plugged into one of the ports.
- CRS328-24P-4S+ - 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 breach 150W consumption.
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 on each PoE-Out state change. Important logs will be added with "warning" topic, informative logs will be added with "info" topic.
To avoid unnecessary logging in cases when PD is not powered because of current-too-low, RouterOS will filter such events, and add one log per every 512 current-too-low events.
Logs can be disabled if necessary:
/system logging set [find topics~"info"] topics=info,!poe-out /system logging set [find topics~"warning"] topics=warning,!poe-out
PoE-Out Warnings in GUI/CLI
To notify a user about important PoE-Out related problems, messages will be shown in Winbox / Webig and CLI interface fields:
1 RS ;;; poe-out status: overload ether1 ether 1500 1588 9204 64:D1:54:61:D5:E0
Webfig and Winbox will notify user under interfaces:
How it works
If auto-on is selected on PoE-Out interface, then port operates in this strict order:
- PSE with low voltage checks for a resistance on the connected port. If detected resistance range is between (3kΩ to 26.5kΩ) power is turned on;
- When power is applied, the PSE continuously checks if 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
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.
If off mode is used, PoE-Out on the port will be turned off, no detection will take place, and interface will behave as a simple Ethernet port.
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 individual port limit allows it.
PoE Out polarity
PSE has following safety features:
PoE-Out compatibility detection
The auto-on mode is considered safe, it will check if the resistance on the port is within allowed range and only then enable PoE out on the interface. The range is 3kΩ to 26.5kΩ
When a PoE-Out port is powered-on, it is constantly checked for overload. If overload is detected, PoE-Out is turned off on the port to avoid damage to the PD or PSE.
In seconds the PoE Out feature will be turned on again to see if the environment has changed and PD can be supplied with power again. That is important for configurations that are not connected to mains (solar installations, equipment running on batteries due to mains failure) so that when voltage drops - overload will be detected and connected devices turned off. After a while when voltage level returns to usual operating value - connected equipment can be powered up again.
Short circuit detection
When power is enabled on PoE-Out port, PSE continuously checks for a short circuit. If it is detected to ensure that there is no additional damage on PD and PSE, the power is turned off on all ports. PSE will continue to check PoE-Out port until environment returns to normal.
PSE with independent 8-port sections (CRS112-8P-4S-IN, CRS328-24P-4S+RM) allows PoE-Out to work independantly from the RouterOS, this means that you can reboot/upgrade your RouterOS and the PD will not be rebooted.
PoE Out examples
RouterOS allows to define priorities on PoE-Out ports, so if your installation is going over power budget, the PSE will disable less important PD with the lowest priority.
Priority of 0 is the highest priority, 99 - lowest
Setting up priority
Example of how to set priorities from CLI:
/interface ethernet poe set ether2 poe-priority=10 /interface ethernet poe set ether3 poe-priority=13 /interface ethernet poe set ether4 poe-priority=11 /interface ethernet poe set ether5 poe-priority=14
What will happen when power budget will go over total PoE-Out limit - first, if overload is detected, ether5 will be turned off (lowest priority), then recheck is done and if 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.
if all, or some ports will have the same poe-priority, then port with the lowest port number will have higher priority
/interface ethernet poe set ether2 poe-priority=10 /interface ethernet poe set ether3 poe-priority=10 /interface ethernet poe set ether4 poe-priority=10 /interface ethernet poe set ether5 poe-priority=10
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.
PoE-Out ports can be monitored using a command
/interface ethernet poe monitor <interface>
[admin@MikroTik] > interface ethernet poe monitor [find] name: ether2 ether3 ether4 ether5 poe-out-voltage: 23.2V 23.2V 23.2V poe-out-current: 224mA 116mA 64mA poe-out-power: 5.1W 2.6W 1.4W
Monitor connected PD with power-cycle-ping feature:
/interface ethernet poe set ether1 power-cycle-ping-enabled=yes power-cycle-ping-address=00:8D:8C:35:54:04 power-cycle-ping-timeout=30s
In this example, PD attached to ether1 will be continuously monitored using a power-cycle-ping feature, which will send arp-ping and wait for a reply. If PD with MAC-Address 00:8D:8C:35:54:04 will not respond for more than 30s, the PoE-Out port will be switched off for 5s.
In cases where a PD does not power-up or reboots unexpectedly when powered from your PSE, it's suggested to 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 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.
- Chech 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 pinout can be unable to powerup from all PSE. Check PD datasheet.
- Incompatible resistance - PD resistance on spare pairs should have range from 3kΩ to 26.5kΩ (For Passive-PoE) and from 23.75kΩ to 26.25kΩ on af/at.
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.
All MikroTik devices which come with RouterOS 6.x already support the latest PoE-Out firmware.