I bought a Mikrotik HEX S router and a Ubiquiti AP-AC-Lite as an access point. When the AP is connected through its original AC power adapter everything works perfectly fine. When connected to the POE port on the Mikrotik, some issues start to appear.
There is no internet connection. (The AP has always the same IP configuration)
After a while the AC just reboots itself periodically every 5 min.
It also reboots immediately after connecting a PC, smartphone, etc… to the APs WiFi.
I got a feeling that the issue here is that the POE port doesn’t deliver enough power to the AC. Maybe some more experienced users could have some suggestions. The POE settings are on default.
Does this need some special configuration i am missing? or maybe this two devices are just not compatible?
Depends, MT POE is not necessarily standards compliant and it thus potentially not fully compatible for the ubiquit if ubiquiti is rightfully expecting the standard.
QUOTE: PoE out Passive PoE up to 57V is not standard.
The standard demands some handshaking back and forth to ensure that the power is acceptable to both units.
Since the MT does no handshaking (passive) the ubiquiti firmware would be lost if expecting that communication…
standard
Power management Three power class levels (1-3) negotiated by signature
Passive
In a passive PoE system, the injector does not communicate with the powered device to negotiate its voltage or wattage requirements, but merely supplies power at all times. The common 100 Mbit/s passive applications use the pinout of 802.3af mode B (see § Pinouts) – with DC plus on pins 4 and 5 and DC minus on 7 and 8 and data on 1-2 and 3-6. Gigabit passive injectors use a transformer on the data pins to allow power and data to share the cable and is typically compatible with 802.3af Mode A. Passive midspan injectors with up to 12 ports are available.
Passive PoE power sources are commonly used with a variety of indoor and outdoor wireless radio equipment, most commonly from Motorola (now Cambium), Ubiquiti Networks, MikroTik and others.
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Looking at the AP_AC_LITE
Power Method
-802.3af/A PoE
-24V Passive PoE (Pairs 4, 5+; 7, 8 Return)
It looks like the Ubiquiti should accept the passive power from the MT HEXS, the only unknown for me if is if MT is using the same pairs pattern etc…)
@anav i don’t understand the theory of af/at POE standard, we are talking about passive POE here…
Mikrotik uses power on Pins 4,5 and 7,8 …
Also, what do you mean 57V is not standard ? Since the Hex can take a DC input of 57V according to the specs then it can as well supply with the same voltage through its POE out Port…
A CRS112 for example that has a 28V DC adapter, it will supply with 28V a device that accespts passive POE…
The HEX, comes with 24V adapter so it will supply with 24V through its POE out Port…
Also, unlike POE, POE+ and POE ++ (af/at/bt) that perform a check between the PSE and PD (power sourcing equipment and Powered Device) the passive POE does not perform any Test, just supplies the Voltage…
That is not true.
All mikrotik devices capable of PoE-out check whether connected device can be powered by PoE, or not.
Of course, if you don’t specifically set poe out mode to “forced on”.
@xvo that is an auto sense feature and has nothing to do with any protocol or can be compared with the handshake between a PSE and PD like on POE af/at/bt…
auto-on - the board will attempt to detect if power can be applied on the port. For power-on to happen there should be resistance on spare pairs in the range from 3kΩ to 26.5kΩ
That is what the auto feature does… Unless you compare that kind of check with the Protocol of af/at/bt POE you are talking about different things…
The point being the poe out from the HEX does not meet a standard, and thus the passive output of the hex to the passive input of the Ubiquiti cannot be guaranteed although likely.
I would only be brave enough to say that passive hex can feed another passive expecting MT device.
It is obvious that you do not know how the handshake on non passive POE works… so its ok with me…
I did compare this with how passive POE works… what you are saying is irrelevant because you keep comparing an auto feature with a whole POE Standard…
So why dont i just have an auto/forced-on feature on af/at/bt ?
One more example, lets say i connect a device on the POE out port that must get 30V to work properly, but since i have a 24V DC on the Hex, the device will get 24V right (if they are enough to power it on ofcorse) ? Although that is a users mistake, can you point me as to where the Test did take place ?
I know, how handshake on non passive POE works.
But I don’t see how is it related to what I wrote?
I didn’t compare anything with anything at all.
You wrote:
the passive POE does not perform any Test, just supplies the Voltage…
And that is misleading and not true: one could easily think, that is not safe to connect non-PoE device to mikrotik’s PoE-out port, which is untrue.
That is all.
If being wrong offends you so much - check your info before posting, not after, like you did here.
I am not offended… ofcorse you can disagree with me…
But i clearly compared the POE’s handshake with the Passive POE… And you say that i am wrong because there is the auto feature…
If that seems relevant with the comparison i did well then sorry @xvo… maybe its my mistake…
No, I’m saying that your are wrong, because Mikrotik’s passive PoE do perform tests before applying power and that is the default behaviour.
And when you say now:
But i clearly compared the POE’s handshake with the Passive POE…
It is not clear at all. Because you never compared handshake and no handshake.
You compared tests and no tests, always on.
And that is the only reason I decided that I should correct your statement.
Ok so the auto feature, since as you say Tests are performed, it takes into account the power classification of the Powered Device and it does supply Power accordingly, right ?
Or can you be more specific on the Tests that do take place ? What are those Tests in specific ?
A source would be appreciated…
As far as i know, mentioned it earlier already, a resistance check on PD takes place and the device is powered on or not. Thats it… Tell me what more is taken into account so that i understand…
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