Mikrotik AC PTMP Problems - SXT G-5HPacD

RouterOS Wireless Networking
1

Hi All,

We have had great success with AC PTP links. Netbox 5’s etc… but we are having trouble with our first AC PTMP setup.

We are using:

SXT G-5HPacD-SA (90 degree) as our Sector AP
and
SXT G-5HPacD (Clients) as our Clients

All using Router OS 6.24

All works fine when only 1 Client connected.

In a noisy enviromnment we are getting approx 130Mbps Throughput to client when only 1 client connected

But this drops down to anywhere between 15Mbps and 45 Mbps when second client connects.

It doesnt matter which client is or isnt connected, So its not a problem with a particular client.
Link distances on both are <1km

RSL of the clients at the AP is -37dBm and -41dBm

We are using NStreme as during our tests this seemed the best (marginally over 802.11ac).


I’ve tried everything I can think of.

  • Different Channels
  • Reducing TX power of both clients and AP
  • Changing to NV2 and 802.11AC
  • 20,40,80 Mhz Channels

And a range of other things.

I’m beginning to wonder is this just a glitch with Mikrotiks 802.11AC PTMP setup?

Has anyone else seen this problem?

ANy help advice would be great.

The RX rate at the AP seem to jump from 6Mbps to 780Mbps…
But I’ve seen this on PTP links and when you push traffic through the Rates climb up and the link performs perfectly.

Thanks,

Tomas

2

Hi,

first please reduce TX-Power, so you get RSL arround -60 up to -65 (you don’t need better, ‘louder’ signal) and the receiver will thank you for that. Also lower TX-Power gives a better quality (checked variuos times with a prof. spectrum analyser here).

All your test are done with 802.11ac, please try your setup using 802.11n instead of ac, I think your problems are solved - we see this in lot of real world installations. Most of the PtMP links we support runs with 5GHz 802.11n only and NV2 (here NV2 works better for us as NStreme) in comparision to PtP links, where we mostly go back to NStreme (as noted here also by lot of other users).


Regards
Lutz

3

surely I would follow Lutz advices ..and I would also try to tweak interfaces queue (starting from sfq to bridged Ethernet)

4

Thanks I will try.

But, I had reduced TX power early in my tests, maybe not as low as -65 though.

Also, why does it work fine with 1 Client?

And basically is your experience that AC doesn’t work very well in PTMP? As moving back to N will obviously limit potential speeds?

Thanks for advice, I will try tonight and let you know how I get on.

Tomas

5

Hi tommk,

did you have any luck solving the issues with your PtMP ac network? We’re also looking at using the Netbox5 as an AP for a PtMP environment, but have seen a few reported issues, so I’m thinking maybe we should rather hold off or go with the Basebox5 and stick with N.