How much Bandwidth needed for 4 EPMP 1000 AP’s

Hello,

I am curious as to how much bandwidth I really can utilize for 4 5ghz Epmp 1000’s on my tower. Each epmp has a max throughput of 200mbps, I have a mikrotik router capable of 10G throughput before the AP’s.

Because they each do 200mbps, what is the maximum bandwidth I can utilize for these epmp 1000’s? Do I need an Internet source of 800/800mbps since each will do 200mbps throughput? Or do I only need an internet source of only 200/200mbps since they will only push that much throughput? I currently have a 500/500mbps fiber line feeding these AP’s. Is this too much? Am I leaving unutilized bandwidth on the table? Or do I need 800mbps because I have 4 radios (200mbps throughput x 4 epmp 1000’s = 800mbps) ?

Just a little confused on how throughput works in these. I don’t want to overpay for bandwidth if that makes sense.

Thanks!

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Man… where to begin… you might want to consider hiring a consultant or someone that already operates a WISP to help you through all of this. I feel like a comprehensive response is a bit much to ask from this group… but maybe someone else will chime in. A few items to point you in the right direction:

  1. While a manufacture’s radio might say it’s capable of up to 200mbps throughput, that’s usually rarely possible in real world scenarios. There are all kinds of factors that determine what kind of real world throughput you’ll see. Secondly, they’ll typically never be full duplex (200mbps up and down at the same time). For an ePMP 1000 under ideal circumstances you might see around 100mbps aggregate.

  2. Assuming you’re starting a WISP (wireless ISP) and your customers are mostly residential, the majority of your traffic will be in the direction of the customers (downlink), and only a fraction away from the customer (uplink). Furthermore not all your clients will be using the internet at the same time, this allows you to oversubscribe your internet source.

  3. Just because your Mikrotik has 10gbps ports doesn’t mean it can actually push 10gbps of real world traffic. Again, just like point #1, different configurations and types of traffic can drastically reduce the real world throughput of a router.

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James, Let me help out here a bit (maybe this helps, or maybe this is more confusing - LOL)

When a spec sheet says 200 Mb/s, you have to look at the conditions the spec sheet says. Normally, that is at highest modulation (which is saying signal to noise ratio), at the widest bandwidth configurable. When the equipment is installed in the real world, We may be using a narrower channel than our max spec, we may not have all of our SM’s capable of 30 dB SNR. To approximate your net throughput on a sector, you need to calculate the weighted average of the SNR’s that your SM’s are reporting. Then you look to the spec sheet to see what the throughput is at that calculated SNR and at the channel size you are using. Let’s call this value ‘net throughput’.

In an example of no specific equipment, lets suppose our spec’d throughput is 400 Mb/s @ 80 MHz channel. Max modulation level is QAM256, which needs > 28 dB SNR to support that bandwidth. Our spectrum won’t let us use 80 MHz channels - too much interference, so we are using 20 MHz channels instead. That means our new max throughput is 100 Mb/s @ 256QAM: 1/4 capacity for 1/4 bandwidth. We calculate our weighted average of SNR at our known SM locations - our calculation says 18 dB. Our throughput table says that we can support 260 Mb/s @ 80 MHz @ 16QAM, which requires 13 dB SNR, and QAM64 requires 19 dB SNR, so our actual performance will be somewhere in the middle. Back to our 20 MHz channel, and our 260 Mb/s is actually 65 Mb/s @ 20MHz @ QAM16.

In the ePMP1000 spec sheet, it says that expected t/p is more than 150 Mb/s @ MCS15 (which is QAM64 5/6) @ -66 dBm RSSI. The theoretical noise floor on a 40 MHz channel is approx. -92 dBm (thermal noise floor + noise figure of the ePMP1000). -66dBm minus -92dBm = 26 dB SNR (that is signal above the noise). The sheet also says that MCS0, which is BPSK, or 2QAM, needs -90 dBm, or about 3 dB SNR. You can create a graph that has MCS on the vertical axis, and SNR on the horizontal axis, and you can estimate what your net throughput will be from your weighted average SNR calculation. Without going too deep into modulation theory, QAM64 supports about 5 bits/second/Hz throughput (that is where the 200 Mb/s estimate for ePMP1000 comes from: 40 MHz bandwidth x 5 B/s/Hz), and BPSK supports about 1 bit/sec/Hz, which is about 40 Mb/s.

This calculation is the sector aggregate throughput: DL + UL = aggregate. Since the ePMP is time division duplex, we spend some time in DL (AP to SM communications) and some time in UL (SM to AP communications), controlled by GPS synchronization, so the expected throughput in each direction is a function of the DL/UL ratio you have selected.

I hope this helps.

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I think if you look through these forums you will find that on average the most a 1000 AP is going to move in one direction (download usually far more than upload) is around 60Mbps if you are using 20Mhz channels and maybe around 100Mbps down if you do 40Mhz channels (we run 20Mhz channels so I’m just kind of guessing based off numbers from a couple of micropops that we did run with 40Mhz channels).

If you are very strict about only installing customers with perfect links then you will see a little more.

We have one tower that moves data for 11 5Ghz AC APs , 5 900Mhz 450i APs, 3 2.4Ghz APs with 310 customers most of them with 30Mbps service. The tower has a 10Gb fiber connection to our NOC/Internet connection which is 10Gb

For us though the only thing the vast majority of those customers care about is that their Netflix , Hulu, HBO don’t buffer and for the most part all 310 of those customers are satisfied with their service.

I would also note that a few years ago a company that had never done internet before bought my WISP. They understood nothing about being an ISP and were convinced that if we built out a FTTH network and offered Gigabit service then we ourselves would need 1Gb of bandwidth for every 1Gb customer we got. I could not make them understand that wasn’t how it works so I decided to show them. I had a very small town (like 148 homes 3 businesses in the whole town) with 110 FTTH customers and I turned every single one of them up to 1Gb. 110 customers with 1Gb internet. Once in a while I’ll see one of them sustain a couple hundred Mbps or maybe when a big Xbox patch/game releases there will be a few doing hundreds of Mbps each but on average the usage for all 110 1Gbps customers was a shock to them. I just left them there so for a couple of years now everyone has had 1Gbps Internet;

Here is an ePMP 3000 AP (Cambium 70° Sector) 20Mhz channel, 39 subscribers (all AC clients all) all but 6 are DS9 on downlink the rest are DS8 except 2 DS7 and almost all with 30Mbps rates;
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The most populated ePMP N access point I have is a 2000 with 21 customers and as you can see from the frame rate flatlining in the evenings, it needs to be split;


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So far you have been given the meat and potatoes of WISP considerations, but it really boils down to:

  1. how many customers you have on the system.
  2. The packages that are in use, the mean average package throughput of all your customers and make sure to have at least twice (you can get away with less but you do not want to) the bandwidth of the max package in use.
  3. Your over subscription rate (how many times you resell the same chunk of bandwidth and hope that nothing goes sideways)
  4. How good of a name you want in the business.

Honestly, if you do not have a good grasp of network engineering then you really should seek a consultant to help you. We are not trying to be mean and we can not teach you everything over the forums.

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Very interesting tread! I’m glad to know about practical experience in bandwidth planing.
Before I used multiplexing coefficient 10: each 1 Gbps uplink could be sold to 10 users. But it was for pure Ethernet networks. And of course not for other ISPs as customers.

a 10:1 on a 1gbps in an ISP network would have you wasting money and bandwidth unless thats 10x 100mbps customers paying for dedicated service, in which case they should be paying enough to support that. In a LAN environment it is easy to provide bandwidth but in the WAN side there is a lot more going on than just throwing money at it.