Big scale 'interop' mode usage

Anybody that can share experiences in the usages in Point to “Many” point networks?
Like 40+ non Mimosa clients connected to An A5 of A5c?

We have 2 A5’s running with some 45 Mikrotik (‘n’ protocol SXT) clients each and one A5 with 64 (mixed but 80% ‘ac’ SXT clients).

The latter has issues for months and together with Mimosa we tried to nail the problem but so far to no avail…
Even when the clients are brought back to only 34 we still have occasional ‘network storms’ meaning several clients disassociate or package losses are so high traffic is not possible.

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I have a network with a5C with 33 CPE between Ubiquiti and Mikrotik-SXT, so far I suffered a little to maintain stable latency between 3ms and 5ms and rare 8ms to 13ms. @Rudy how is behaving your network where there are 45 CPEs, the latency is stable and the throughput high?
Sorry for my English, I’m using a translator.

We cut from UBNT to Mimosa a few months ago, and ran everything in Interop mode with the UBNT CPEs while we cut everyone over to C5s. We had nothing but trouble until we switched to SRS. Main issues were clients randomly disassociating and high packet error rates. All of these were resolved after switching to the SRS protocol, however due to the increased overhead clients with worse RSSI saw a decrease in service quality. That was resolved by installing a higher gain C5c.

@Bennett. Sounds to me your RTS/CTS settings were not configured properly on the Ubnts.
The proper RTS/CTS setting (always ‘on’) is very important. If not your network has many ‘collisions’ and therefore re-sends of data and your network deteriorates fast.
I have had several A5’s with 40-65 Mikrotik clients. First we didn’t use RTS/CTS to the full and the network only worked averagely. But then after the fine tuning of rts/cst with some more tiny settings the network improved a lot.
Now we are on SRS full. That is even better but also because the C5’s antenna is better (shielded) and higher gain then the SXT’s we’d used before. As we all know, 802.11ac like high gains(signal to noise ratios to reach the high mcs rates.
So you have to take in mind the type and quality of the antenna as well in relation to the spectrum usage. (we are in a very congested area.)


I testing a5 with 40 clients sxt ac and somedisc 5 ac, signal betr of -59, with cst rst,thresold 256, long preamble, client noise imune,default power… Any advince more to improve?
The result is that some clients has bas ping abot 100-400ms, disconection, low speed when cpe are near 50 m…

Any solution?go full srs is so expensive cpe, will is it change? How is the experience full srs vs a5 sxtac?


The only thing I can advice it to remove the RTS/CTS threshold set to ‘0’. Meaning it is always ‘on’. According some white papers I red some years ago the University of Tokyo made a thorough study on the advantage and setback of use of the RTS/CTS and the conclusion was that in all circumstances it is best left ‘on’ at all times. The extra overhead or the extra protocol data is well been compensated for the much better performance. Always…
So I set it always at ‘0’.

My network in fact runs with 80% of the clients better then -50dBm signal. When its -55 to 60 I try to improve it by better antena or other AP.

Another suggestion is to lower the amount of associated CPE’s. It depends a bit on the average usage of the clients. If you only have occasional top data rates and data consumption on your P2MP network it would work out fine. But if you have regularly several CPE’s trying to get top speeds and long running downloads, well the airspace (spectrum/versus bandwidth) can only give space to su much traffic…

What is your channel bandwidth you work with? 20, 40 or 80 Mhz. I work with 80 Mhz and that is fine even although the second 40 Mhz has overlap with other AP’s for several clients.
When I had all SXT’s (up to 60!) on that AP they all worked in 40Mhz channel.

Every double the bandwidth gives in theory twice as much capacity. So can your client do 50Mbps in 20, it can do 100Mbps in 40Mhz and probably close to 200Mbps in an 80Mbps channel. And in fact those days I have done performance tests with an SXT-ac that could do some 240Mbps download in that full 60 clients P2MP network running while other users produced some 20-30Mbps of traffic as well.

Hi Rudy,

I had 80mhz all sxt ac and some disc5 ac, did you see links downs like 20 or more per day?(may be retries, disconetion duration?? O another thresold)I think is because there is another clients near (noise client inmune enabled), because it is reduced when i change the nearest client to omnitik ac in another frecuency. But omnitik ac only give me about 10- 15 mb per client at -50 and -60 with 4 concurrent use(mimosa get 50-100 and total peaks about 300mb), if only one could get 100mbs , in nv2 and with 802.11 cst rst worse performance. Any solution for has near clients in a5 with out links downs and high ping when use same time? Are you using now a5+mk or not?Will be posible a mikrotik firmware or script srs compatible at least tdma-mimosa?
You are using mk 60 ghz, do you you know if in roadmap, 8 clients restiction is temporal, and will be 50-100 in future with same hardware?or at least new hw?Because 8x3 clients by ap is too low.

Did you test mimosa pmtm for long distances 3km to 8km?will works?


(If you want i could call you or meeting in spain to discurs future and expriences of wisp here.)

So, I can’t comment much on the other issues you are having, but I have run Mimosa Sectors with clients 3-5 miles away. Worked alright when we were below 20 customers, but as we added more we had more frequent and worse issues with packet drops. Overall I would not recommend long distance non-TDMA links. You get to needing +25 dB antennas too quickly.

Hi Martin,

First of all, October 5th there is a Mikrotik MUM in Valencia. We should meet there. Send me a pm to

About your comment:
I don’t know anymore if we did have many disconnects or not in those days. The first A5 we’d used was installed late 2016 and it worked fine. I could have up to 66 clients to one Mimosa A5 connected and could just take one and run a download of up to 250 Mbps. With two or more can’t really recall anymore but still close to 100 Mbps while there was still other background usage of the clients with 1-20 Mbps variable. With a SEXTANT connected beside the SXT-ac I could still almost run wire speed (95 Mbps)
The settings of the SXT are pretty basic as they come but with RTS/CTS enabled to work always. I always have ANI ‘on’ on all my units.
One important thing I did was to set these very short range SXT’s to a low power output. So all associated clients where ‘hitting’ the A5 with sort of similar signal. I did work with a signal of between -40 and -55 in principle and only some could do with -60 but that was the limit.
(You have to bear in mind that in a normal 802.11 csma protocol, even with RTS/CTS enabled, all the clients should have a sort of similar signal at the AP. Otherwise strong units might sort of ‘over-shout’ weaker units.

Then spring 2017 we changed all SXT’s for Mimosa C5’s since I wanted to try these and then I could also install 3 more A5’s in the short region. (All within 500 meter radius!) The idea is was to finally run a full synchronized network and all units in 80Mhz channel bandwidth.

This didn’t materialize completely although the C5’s do perform a bit better than the SXT’s. Probably because the C5’s are shielded and are a bit higher in gain.

But yet again, signal is king. We basically don’t allow units with less then -60dBm of signal. We aim at -50dBm.

And that’s why I still have doubts on 500+ meters links. The problem here is that the C5’s only work in 27dBm and the A5 only in some settings can get to work with 30dBm. This where a Mikrotik Netmetal can do 31dBm and Mikrotik LHG’s or DISC’s do better then the standard C5.

So now we need to look for C5s with bigger antennas. I found a nice 24dBi antenna and actually we are going to give them a try for 2-3km distance in the weeks coming.
It will be a hazzle since we now run Mikrotik Netmetal on a 18dBi RF elements Dome so we first need to change all 25 clients into C5c’s with antenas (some have/need even higher gain then 24dBi, they have a LGH-5acXL now)… This is quit a costly adventure where no success is guaranteed.

But a year ago a was so enthousiast about the Mimosa still (that has tempered a lot since :frowning: ) that I bought 30 of these C5c’s. So I’d better put them to some use now…

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When I was introduced and became enthousiast of Mimosa it was in the pipeline that the limit of 44 clients in SRS mode was to be raised.
I needed that since I have to serve almost 200 clients in just a 500 meter radius circle. Too many AP’s would be come too costly both in money as well in respect to the spectrum. (Even although they said I could run synchronized…)

So I started with 3 AP’s. One with 44 clients, one with 42 and one with 40. When we had some association problems and we spoke with the helpdesk a month ago (I mean, still no sign of 44+ clients in tdma mode) the technician actually said; “44 clients!?! Way too much. You should stick with 35 max…”

It seems to me Mimosa found that some of their promises where actually dreams…

So here we are now.
I work in a region with overused spectrum. Some 60 20, 40 or now even 80Mhz channels in use in the 5Ghz band.
I have towers that need to server 100+ clients. So I already have several sectors running 30-40 clients…

Apart from beeing very costly to change them all for (whatever other) brand, with Mimosa I wouldn’t know how to server them all…
The Mimosa is still more picky on the channel use. Especial when 40 or 80 Mhz wide channels are used. It’s virtually impossible to ‘fit’ or ‘squeeze’ a Mimosa AP in a relative free spectrum part.

I can find some part where I can get 30 or 40Mhz wide spectral space relative ‘free’ but when I then try to set the Mimosa AP for that space it is not allowed because the radio only works with the IEEE channels. With Mikrotik I can basically change a channel per 5 Mhz up and down and can even go ‘out of band’ if needed to get some signal to clients…

I know that Mimosa now has some frequency granularity but its still not as handy as what we have now.
Secondly, we went for Mimosa with the promise of delivering 100 or Mbps to the clients. Well, that is only possible with 80Mhz wide channels and high signal levels.
When you have to fiddle with 20 or 40Mhz wide channels than signal is king again and with other brands it just much easier, and cheaper, to deliver more power to the clients.
And with the latest ROS and new cheap devices like the SXT-sq-5ac, LHG 5-ac (an absolute good device!) and the DISC-5ac I can get more signal from the AP with more flexibility and for a fraction of the price of a Mimosa setup… And we do deliver now 30-50 Mbps to the clients what is more then most of them need anyway…

Hi Rudy,
How do manage to get “clean” spectrum from MT “ac” AP’s (no spectral scan function) or do you N AP’s with AC CPE’s?