It is typically created by taking the maximum possibly PHY rate (more on that in a second) on each radio, and adding them together. This number published on the data sheet (and also frequently wielded by consumer AP marketing) is completely bogus, but marketing loves to show off big numbers.
This is probably one of the most egregious attempts by the marketing department to ignore reality. (If you’re still in school, pay attention: you will use this stuff in real life!) The Engineering Winging it: Ur doin it rong. So let’s pick this design apart, piece by piece… (yes, I’m gonna pick on Ubiquiti for a bit here, because their UniFi brand is often thrown about as a solution to all your wireless problems by people who don’t actually understand how wifi works – but these principles apply to any vendor – no vendor has a magic bullet, you still have to do the engineering)Ĭaution: Math (or at least some basic arithmetic and some elementary statistics) ahead. There is no amount of marketing copy that can ever overcome the fundamental laws of physics. And then when you fill the room up, the whole thing collapses, everyone is complaining about how it doesn’t work, and you’re left wondering why.īecause that’s not how any of this works.įor starters, never believe the data sheet. Easy job, under a thousand bucks for the gear. So you should be able to get 7.6 Gbps, divided by a thousand seats, which gives you 7.6 Mbps per client, and you’ll need a 10 Gbps switch. The vendor data sheet says that you can do 500 concurrent clients per AP, so that means two APs (let’s say three just for redundancy), and each AP can do 2533 Mbps. So let’s say you have a 1000-seat sanctuary where you want to use a Ubiquiti Unifi HD access point because that’s what your colleagues on social media recommended. Try to do a predictive model using Ekahau, to place the APs in exactly the right spot, and without ever surveying the space.Then divide that capacity so you know how much bandwidth you get per person. Figure out your capacity by taking the AP throughput (again from the data sheet) and multiplying that by the number of APs.Count up how many seats there are, divide by some number of seats per AP (usually based on the AP data sheet), and then figure out how many APs that gets you.In this post, I’m going to get into the nitty gritty details of making sure that not only does an auditorium have sufficient wireless capacity to meet the connectivity needs of the space, but also to have realistic expectations of what the performance will look like in order to build sufficient backend networking infrastructure without needlessly overbuilding it.Īuditorium design should be simple, right? Here’s how I have seen it done, way too many times to count: Those who have known me for a while probably know that this type of auditorium is kind of a sweet spot for me, having done designs for a number of church sanctuaries of various sizes. I was recently (March 2021) tasked to do a design for a small 450-seat auditorium and provide capacity and throughput numbers.
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