Replace ePMP 1000's to increase network capacity

I am looking for help in choosing equipment to increase the capacity of our backbone. We currently have 4 towers linked with ePMP 1000’s and the same for access points on each tower to serve a community of approx. 100 homes and businesses. We just hooked up to fiber and our capacity is now enough to deliver nearly 500 Mbps to each client, but we would like to be a able to deliver packages of 10 to 50+ Mbps. With the ePMP 1000 backbone we can only manage about 7 Mbps before frame utilizations start hitting 100%. I am currently testing an ePMP 3000L on one of our heaviest zones, and with only 18 clients it is already reaching about 70% frame utilization with packages averaging about 10 or 12 Mbps. Any suggestions on where to get help with this?

Post screen shots of:
Configuration → Radio
Monitor → Wireless
Monitor → Performance

FWIW, here is an ePMP 3000 with 20 clients. It’s the middle of the day, so not too busy…
Most peaks around 60 Mbit, but 133 Mbit at the moment, and a 10 min long 122 Mbit about 2 hours ago.
Frame time is 25% right now. That bounces from about 17% to about 37% as I was watching it.


But a lot of “frame time” depends on how your settings are configured, and how efficient your SM’s are (SNR and Modulations). If everyone is a MCS9 then things will be cool. If you have a bunch of MCS4s and MCS5’s then they will use a LOT more time.

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Thank you, I see now that we do nat hav3e even a single client above 7. RSSI’s are good, so does this suggest perhaps some interference? I followed the spectrum analyzer and chose what looked like the middle of the clearest range.

So in your opinion I should be able to just swap 1000’s for 3000’s and get the higher capacities with better links?

I think that just indicates that he has all N gear clients… Force 180s, Force 200s, etc and no Force 300 AC gear clients. But yes, that will eat up about 50% more airtime right there.

Yes, I am starting to figure that out…we jumped on with Cambium 7 years ago to migrate from Canopy. Went through the struggles of software updates, etc., and now we we have to change client equipment again to be able to deliver even 20 Mbps to <20 clients on any single AP? Is there any discount or buyback/ recycle option? We are now sitting on 16 Gbps of capacity after years of struggle, and no way to deliver it…have spent lots of $$ with Cambium and cannot seem to get any direct assistance and help in choosing equipment and network design.

Where are you located? Have you tried reaching out to your Cambium Regional Sales Manager (RSM) or Cambium Regional Technical Manager (RTM)?

thank you Eric…we are in Mexico and have tried to contact Cambium via a support request, but that seems impossible for this sort of request, so I called Cambium headquarters and seems they are on permanent voice mail vacation. Never heard of or from an RSM or RTM. I appreciate your response and any direction…but if we have to rebuild the entire network again I am very open to and will be considering another product or company.

Hi Tropicotto,

Ismael Aguilar RTM - Mexico, can you send me your contact details, so I can give you a call.




Mathematically, if you want to provide 20mbps to 20 clients with a committed information rate, you need a wider channel. Also, are you talking symmetrical speeds, or asymmetrical speeds?

What is your customer demographic? Streaming video, or gamers? Wildly different use profile there.

As for backhaul, if you’re staying unlicensed, the ePMP PTP400 series is substantially better than the 300/3000 series.

As for getting buy-back, I wouldn’t model around that. I would model on replacing a fixed wireless network every 3-5 years. If lucky, you’ll find a buyer who will take the gear off your hands for about 10% what you paid.

ePMP is actually pretty friendly as far as upgrades go by being both forward and backward compatible with their N and AC based gear.

You might be able to stretch the life of your N clients by going and upgrading your heavy users first. If it’s a light user, leaving them on an N client won’t hurt you too badly. You should definitely fix, or remove the customers with signals less than -70 there. That one with a -76 especially is not your friend.

Just for reference, this is an ePMP 2k with all N clients running a 20MHz channel.


If you don’t want to truck roll all your N gear clients (and who would!), then if they’re spaced out your bet is the MUMIMO of on the ePMP3000 as opposed to the 3000L. I’m not sure with your low subscriber number on that sector and low frame utilisation if it would be hugely beneficial though. Is there scope to use a 40MHz channel?

I presume you’re using connectorised clients with large antennas at these distance?

Also, what’s the max MCS rate on the 3000L when the TX is set to 27dBm?

Spec sheet indicates -66 per chain to get MCS 8 on your downlinks.

Personally I’d swap out or upgrade with larger antennas your worst clients and your busiest clients.

MU does not work with N radios.

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Thank you all for your help, I have been working the past few days (all-nighters unfortunately) to open channels to 40 Mhz where possible and have seen an increase in throughput along with a decrease in frame utilization. There are clearly things we can do to maximize efficiency and capacity with the 1000’s we have now.

This however raises another question though…in one link, we have a problem with the uplink MCS drops from 12 to 6 when opened to 40 Mhz. The RSSI is -62, but ch2 is around -80. I understand I need to improve alignment or change equipment in that case, but the question is ‘should I put importance on capacity or MCS?’ Seems to me so far to be more efficient at 40 MHz with 12 MCS down even though the up is only 6…or should I focus more on MCS? At 20 MHz on that link MCS is 12 up and down, 27 power on the master and 21 on the slave. Tried to force to 27 on the slave but still fluctuates to 21 dropping MCS.

I will reach out to Ismael soon also, thank you for the contact info.

Yeah but as he upgrades the worst / busiest to force 300 CSM they’ll benefit won’t they?

Most radios can’t manage their top MCS rate when the TX is set very high. I have no idea of the max TX for ePMP3000L to get 256QAM@40MHz but if it’s the same as ePMP3000 its 28dBm at 5.7GHz which is quite impressive. The legality of doing this in your country is an important consideration.

For most WISPS, your subscriber units are usually receiving not transmitting so their TX and MCS doesn’t matter so much, just let ATPC do its job as you don’t want subscribers too loud.

If one of the chains is -80dBm that wouldn’t normally indicate either

  • misalignment
  • fresnel incursion (e.g. trees)
  • client is outside sector azimuth or elevation.
  • a faulty lead at the client end if it’s connectorised radio.

Capacity vs MCS? The answer is usually capacity but it really depends on your environment. Most of my towers are so busy or there’s so much interference from other operators that 40MHz channels are just something to dream about. I try and get as much syncronised as possible for channel reuse and make sure I use high gain subscriber units as the pick up less interference due to their tighter beamwidth

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The e3kL is not a good radio for your needs. Bandwidth wise its can handle it but the number of subscribers will be a problem especially in the evening when everybody is online. You would be better off with e3k radios and using MU-MiMo. But again your budget and service distance is also a factor. 4 e3kL is about the same price as 2 e3k and you would need to change the antennas. This would not make sense if your only servicing a town but not the surrounding area, but if you were servicing outside of the town as well, then the cost of the upgrade which would allow for closer to 40 users per sector would make more sense. Keep in mind if the town is expanding or not as you may not want to spend too much on a town thats shrinking.

We have e3kL’s in the field and with 25mbps packages we are seeing very high CPU utilizations in the evenings with only 15 to 18 subs using 20Mhz channels. 50Mbps plans would over utilize the e3kL.

Would you mind posting a graph/image of your evening CPU/throughput and connected stations as we’re offering 50Mbps plans with e3KL (plan is to upgraded them to e3K if they get too bus)?

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