I have a question about the 802.3af support in the mAP.
I picked up two of them in hopes I could use them in a specific deployment scenario.
While they both boot up and work fine in hard power, USB power, and passive PoE… I cannot get them to power up at all off of a standard 802.3af PoE switch.
So am I missing something? Or does Mikrotik mAP not support standard 802.3af?
I have tried the following switches:
Veracity Global 5 port PoE
Netgear GS110TP
Netgear FS116P
Dell PowerConnect 3448P
Alcatel Lucent 6400P
Alcatel Lucent 6850P
Foundry SuperX
mAP boards should work with 802.3af standart with crossover cable in mode B. Make sure that your PoE-OUT supports 802.3af standart and, if it still is not working, then forced on mode could help.
MikroTik, sorry about the rant but please don’t claim “802.3af support” as that standard requires PDs to accept both modes A/B (PSE is free to choose any one of them), both polarities, and 1500V isolation. The proper (not cheapest though) way to implement 802.3af PD is to use two bridge rectifiers and isolated (!) DC/DC converter. Otherwise, if one “almost 802.3af but not quite” PD has negative ground and another one has positive ground, you suddenly have 50V DC between the cases of the two devices. While 50V DC doesn’t sound very lethal, it could still be dangerous for someone working on a roof/mast etc.
I use Rocket M5 Ti APs which support 802.3af properly as PDs (except their supplied 48V PoE adapter is passive and not proper 802.3af PSE, best to discard it so it won’t accidentally fry anything and simply use a proper 802.3af switch instead, works fine for me with Nortel 5520-24T-PWR and SMCGS8P-Smart switches). Would like to start using MT’s new 802.11ac stuff (UBNT is not there yet, PtP only for now) but will have to wait until 802.3af is done properly (not cheaply).
And do not be surprised when af pass-through won’t powering chained af device because two devices exceeds PSE power limits.
I think mAP PoE out is useful only as replacement for MT PoE injector to power some SXT or something like that outdoors.
The PSE is often a switch with many ports which power other (truly 802.3af standard compliant) devices, so it may not be practical to change it.
Good to hear there are plans for improvement, better late than never. IMHO, passive PoE should have been replaced by standard 802.3af as soon as gigabit PoE was introduced. The setup I’m working on has the PoE switch powered from -48V DC battery backup (positive ground, it also powers licensed microwave links where -48V DC is passed through the coax from the IDU to the ODU) so I must be careful to only connect proper 802.3af devices with isolated DC/DC converters.
your PSE should not have any problems with not powering mAP or any other device that is not supporting positive grounding. At least RouterBOARD products should just not work. As only RB800 has galvanic isolation and can work with any power source. The rest of line-up is with negative grounding.
marizo 802.3at can provide of up to 30W to the wire. Maximal power consumption of mAP is 2W with usual power draw of ~0.5W so you can calculate how many mAPs can one such port power up (with restrictions of negative ground, ModeB supported by PSE)
Thanks for reply, janisk.
I was too rude, but i didn’t say it newer works. I just recommend carefully consider hardware choice.
Yes, powering mAP chain from af/at could work, but i can’t imagine why i should do that (update: I can - maybe as cable repeater)
Let me explain what I mean:
There are plenty of different PoE switches, af, at standards, various total power budget; various PDs; adherence to standards etc. There have been cases, when some cheapest 4 port af PoE switch is too weak to power up 4 IP af PoE cameras at the same time. If there were some mAP chained, it could be impossible at all.
But at switches are much more expensive, so the most common are af switches.
Beyond “just a normal PoE switch” that the claimed 802.3af support implies, what are the actual requirements for powering a mAP2n with 802.3af?
The wiki says that “…PDs that implement only Mode A or Mode B are disallowed by the standard…”, so if the mAP2n only supports mode B, then it seems to me that it can’t claim to be 802.3af compliant.
I too have been unable to power the MAP via a PoE switch. I am currently trying with the device that gives me the most options a GS110TP:
Using a crossover cable as requested:
The unit powers up fine with a RB/GPOE
Extremely interesting topic! It looks like nobody managed to provide working example which uses non-mikrotik 802.3af enabled roter/switch and mikrotik mAP 2n (I looked through a lot of open topics but in vain. Everybody faces the same issue).
It makes me feel that we (mAP 2n users) were slightly misled with 802.3af support. Looking forward for mikrotik experts comments and clarification with working examples.
As to me 802.3af support is a key feature for this tiny device
