Epmp 3000 High Frame Utilization despite relatively low throughput


We’re a small WISP new to the Epmp 3000 platform, currently testing it to transition away from Ubiquiti on some of our high-density towers. We’ve got one epmp 3000 AP using the 90 degree MU-MIMO sector antenna serving ten SMs with mostly quite good MCS rates. We’re using a 20mhz channel and 75/25 down/up ratio. Guard interval is set to short, max distance 8 miles.

epmp MCS

However, I noticed today that we’re seeing high frame utilization (peak of 88%) despite relatively low throughput (max 55mbps or so). We had expected to achieve significantly more throughput than this before maxing out the AP, but it’s my understanding that high frame usage indicates the AP is nearing its max throughput. Is there something I’m missing here? Or perhaps some settings we need to tweak?

Here’s a screenshot of throughput and frame utilization:

What firmware version are you running? A similar question was raised in November:

We are on 4.5.5 on both the AP and SMs. I thought I’d post a shot of the AP’s software upgrade page though, just in case there’s any additional information here that might be helpful:


Please upgrade to the 4.6 firmware available on our beta site but more importantly you can ignore the frame utilization number for now and be confident in pushing more data. Can you also do a screen shot of the MU gain on the tput chart?

Keep in mind that the cnMaestro charts are 5 minute average and pretty low “resolution”. If you were to watch monitor-> throughput on the AP at the same time you would likely be seeing much higher throughput, at least in short stretches.

Thanks all for the replies. For what it’s worth, we also monitor with Preseem and I haven’t seen traffic exceed about 55mbps, usually it’s lower. (They provide peak and average stats on their graphs) But it’s good to hear we should have plenty overhead left.

Here’s a shot of the throughput graph with MU gain.

@Sakid_Ahmed, would you recommend 4.6 RC 35? CN Maestro shows me two versions of the beta available.

What embedded Wireless Lint Test shows you when running in dual-SM mode?

Thank you.

Thanks for the suggestion, I hadn’t used that tool before. I used medium packet size and got a an aggregate of 56mbps, 43 down and 13 up. First SM aggregate was 20, second was 35. I tried running on a few different SMs, results were similar. For some reason, the second SM was consistently better, I’m guessing because there was less traffic on that side of the AP, but I’m not yet familiar with these radios or the link test tool…

Hi all. Any thoughts on those test results? Do those numbers look acceptable/normal?

Then it would be nice to see packets per MCS distribution from AP.
For now, I can guess AP is operating on low MCSs, but this contradicts to the first screenshot you’ve attached.

Thank you.

Happy to provide:

Thank you for sharing.
From the screenshot, we can see Frame Utilization is currently at 13.5% level.
If it is increasing up to100% but throughput value is not changed significantly, then it makes sense to open the support ticket.

A support engineer will request remote access and will check your link.

Thank you.

Thanks Fedor. I think we’ll try updating the firmware (Currently I’m waiting on a backup AP to arrive before we do that) If we still have the high utilization issue after that, we’ll open a ticket.

Some tips:
From our experience on field like WISP you need to pass to 40 Mhz. for have more throughput.
There are also some disturb, the best MCS are 9 with 72.8 % when you have high frame utilization you have over the 20% retrasmission.
You have to think in packet per second non in byte.
In real environment with 20 Mhz and 4.4.3 you not go over 90-95 Mega Byte.