Total ePMP throughput ?

Hello everyone, we had 1 AP with 23 stations already connections, we are experimenting very low bandwidht in those clients also we see a exreme high latency/packet loss even 2 seconds  timeout. The aggregate traffic is around 12-16 Mbps when we drop some clients the problem is gone, signals are good SnR too.. any idea ?  

 Show Wireless-monitor screen and Tools-wireless link tets results to CPEs with best and worse  MCS.

Set Subscriber target power level to -55 dBm.  Maybe something wrong with MIR profile, please set it to default and make internal link test ( Tools->Wireles link test) to CPEs with best SNR and worse SNR .

the  wireless link test are good, my problem is he high latency above 1000ms, i just wanna know if the problem is the total troughput or if there any traffic that cause this. Thanks

Are you running in Flexible mode or do you have a DL/UL ratio set? If running Flexible mode, disable carrier sense. Last point, set max range distance to the furthest subscriber in the sector.  Interference comes to mind too so if you can run it in e-detect mode on the AP, you should see the possible interferers.

we discard this. My RF deparment was the first to verify any RF issue. I think is more a customer overload. But Thanks

Hi Aero_Ramon.  I've been following this thread and I'm curious if you are running Flexible mode, or if you are using one of the 50/50% or 75%/25% ratios?

im also following this post... i do have the same problem....low speed but only 3 clients connected...

maximun they reach is 5 down... also latency is too high 

distance is about 2 km and signal is about -65

Ninedd we try all frame ratio and still the problem but at this moment is running 75/25

Ginebra look at my customer ping. Real high latency even in good conditions. 

Hi Aero, 

Have you contacted our customer support engineers yet? If not, please do so at

If you'd like I can take a look at your system tomorrow if you can provide me remote access. You can reach me at



OK Aero, thank you for replying. This is a concern - I thought that the ePMP was supposed to have consistent latency, even at high throughput? I hope that Cambium can help you figure this one out, and I'll be currious to see what the solution is.  Best of luck.  :)

Hi Ginebra254, 

Thanks for the info and sorry to hear you are having trouble with your deployment. RSSI of -65 alone is unfortunately not enough information to troubleshoot your situation. 

What is your interference level?

Have you run a Spectrum Analysis at the AP and SMs? What do the scans show you on your channel and adjacent channels?

Have you run eDetect to see if there are any 802.11 interferers in the vicintiy of the AP and SMs?

Is the AP colocated with other radios? If so, how far apart are the channels on each radio?

Are you using GPS sync or are you using Flexible mode?

What kind of retransmissions do you see under the Monitor->Performance page of the radio?

What kind of MCS spread do you see on the UL and DL under the Monitor->Performance page of the radio? 

If you are getting only 5 down, most likely you are only capable of MCS1 which tells me your site is under heavy interference. What does your UL and DL link capacity and quality indicate?

Sorry for so many questions but there could be many reasons why your throughput is low, the main culprit being poor RF conditions. If you'd like for someone to quickly diagnose your problem, please reach out to our support engineers at



I currently have 20 clients connected to a single radio and everything has been performing very well.  I will be adding a couple of clients in the next week or so.  I'll be interested to see if we start to experience issues.  To be honest it would surprise me a great deal, considering how well it is performing at this point.

OP, when you drop a couple of clients, does the performance immediately improve?  Does it matter which clients you drop?  I see you have a mikrotik router, can you run speedtests across some of your links?  If so, what kind of speeds are you seeing?  More interested in TCP than UDP.  

I know you said 12-16 mbps aggregate.  What percentage of that is upload?

Thanks i sent you an email.

Quick update on Aero_Ramon's issue. 

He is using a 2.4 GHz ePMP radio and after running eDetect on the AP, we discovered 12 to 13 other radios operating on the same channel. The interference level on at least three of these radios where above the UL RSSI of the ePMP AP resulting in a negative C/I situation. This is just the Uplink. Looking at the Monitor->Performance page, we see excessive packet loss and retransmissions on both the Uplink and Downlink. The Uplink restransmissions are clearly explained by the eDetect results explained above. We suspect the downlink to be a similar situation as well. 

Ramon will follow up with his RF engineers to further optimize this deployment. Suggested steps are:

1. Run ACS such that the ePMP AP can find the best channel possible at this deployment

2. Since this is a single AP on the tower (for him) and he is not GPS Syncing, he will switch back to Flexible mode to drop the latency by half

3. Perform eDetect on the new channel chosen by ACS to identify interferers on it to see if the situation is better. 

Unfortunately, his RF environment is pretty brutal and we will continue assisting Ramon to best optimize his deployment. 




Thank you for the quick response, i  will post my results when my engineers works in yours suggestions. 



Also look into using smaller channels i.e. 10 MHz instead of 20 MHz. You may actually get more throughput that way!



Hello Sriram, we have   huge problem here! The thing is  our custmers have NLOS to our tower thats why we are using 2.4 Ghz band. We dont have more channels to play with in 2.4 becuse the AP is US. We re-verify the channels and the one we are using is the clean one.