AF24 connected to WS-12-250-AC - cable length measurement

[IntL-Daniel]

Anyway, does this cause you any real hardship or is it just an insult to your eyes? Cable length doesn't change so there is no need to look at it every day. The only time you may need to look at it is when there are ethernet issues at which time bouncing the port will get you the measurement you need.

Thanks for reply. It is not a question if is an issue which only insult my eyes! Will YOU keep your car with three not working doors because of you travel alone only and do not need other doors yet? I hope not, you (and me the same) are probably IT skilled person and that means that you should expect everything work as is expected. And the behaviour of Netonix vs Ubiquity cable measurement method work in unexpected way (this is my current feeling).

In my example... if you powering AF by Netonix, AF is unable to measure cable length after powercycle by switch. But if you do hard reboot or soft reboot of AF24 or simply disable/enable lan port on Netonix then measurement come up normaly. I believe that if I will powering AF by original POE brick and connect it to Netonix, it will never do this issue even if I will unplug/plug the cable from POE port going to AF. This is for me unexpected behaviour and I am currious what is the reason for this and who is responsible for this. That is all.

[sirhc]

Yes that is a 500mm unit.

If you reboot the radio within the radio UI it will come up with a more "correct" reading however I have found our switches provides a more accurate cable length than the AC and AF units. This has more to do with the PHY chip they are using then any code UBNT wrote just as we did not write the code in our switches that does the cable test.

I think this would more easily be fixed on UNBT side since our switch is almost always coming back with the correct cable length.

I had suggested to UBNT that when it gets this inaccurate <20m result to initiate a re-test but that did not seem to meet with good results?

All I can promise you is when I get some time I will do some testing to narrow down what I think is the cause but I really feel this in on their end?

[IntL-Daniel]

I agree with you that it is more probably issue on UBNT side (but here is still an example with their ToughSwith and PBE 5AC500..do not talk about more or lower correct measurement - but with our 25m long cable I can never see there result of <20m).

I gave you some hints how could be their bug (if it is on their side) solved by your switch. I agree that this is not the right way of thinking but on other side it could be the same kind of solution like for pause frame storm.

[sirhc]

Well yes and no.

Pause Frame storms are a very real issue even outside UBNT and Netonix gear and I think it will become more so with other wireless equipment as manufacturers transition to faster links and 1G interfaces as manufacturers are struggling to incorporate a layer 2 protocol that is not meant to deal with variable capacity wireless links.

Our Pause Frame Storm protection was not invented by us and has been implemented by other manufacturers in the past so it was not an invented here idea, we just did something that we read other manufacturers did but instead of disabling the port entirely we simply disabled Flow Control on that port and it seems to work out good?

Disabling Ethernet communications on a Port's POE turn up or a POE port bounce for X seconds may have other adverse effects to other applications?

As I said I was to play with this when I have some time and see what I can figure out. I am pretty swamped right now so it will not happen soon but this in not a critical issue and only affects an incorrect UI reported cable length.