How many concurrent users can connect to router ... but no slow down?

sheep101

Commendable
Aug 27, 2016
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I have a TP-link AC1750 Archer C7 with these specs >

Supports 802.11ac standard - the next generation of Wi-Fi
Simultaneous 2.4GHz 450Mbps and 5GHz 1300Mbps connections for1.75Gbps of total available bandwidth

So I know if theory router can give out 254 ip addresses to wireless devices trying to connect to it.

I calculated for one user to use 10 mbps but let's double that to 20 mbps, and if I had 50 concurrent users, which means total of 1000 mbps then my router should be able to handle the ups and downs without "too much" slowdown?

What do you think?

 
Solution
It depends. IF you had one wireless "G" device connected at 54Mbit (25Mbit max throughput) then EVERYBODY has to slow down. Why, because the router only connects to one device / band at a time. That is the way WIFI works. Since connections are time multi-plexed, even if there is a 450Mbit device ready to transmit, it has to WAIT for the 54Mbit device. This is one reason to move wireless "G" devices to their own access point.

BUT, beyond that, even if EVERY 2.4Ghz device is a three stream 450Mbit device, the maximum throughput is 225Mbit (1/2 advertised). Why? Because WIFI is half duplex (send or receive, but NOT both simultaneously). So your 20Mbit device, is going to use 40Mbits of bandwidth (in time) and at MOST you could...
It depends. IF you had one wireless "G" device connected at 54Mbit (25Mbit max throughput) then EVERYBODY has to slow down. Why, because the router only connects to one device / band at a time. That is the way WIFI works. Since connections are time multi-plexed, even if there is a 450Mbit device ready to transmit, it has to WAIT for the 54Mbit device. This is one reason to move wireless "G" devices to their own access point.

BUT, beyond that, even if EVERY 2.4Ghz device is a three stream 450Mbit device, the maximum throughput is 225Mbit (1/2 advertised). Why? Because WIFI is half duplex (send or receive, but NOT both simultaneously). So your 20Mbit device, is going to use 40Mbits of bandwidth (in time) and at MOST you could have 9 or 10 devices. BUT most 2.4Ghz devices are single stream 150Mbit devices. So your 20 (40 Mbit) device is now taking about a 1/3rd of the available bandwidth.

Moving devices to 5Ghz helps. Tablets and cellphones usually support 5Ghz. Laptops is hit-and-miss for 5Ghz support. Higher end laptops are more likely to support 5Ghz. A device that says it is an "AC" device is 5Ghz compatible.
 
Solution
depends on the router. a cheap consumer $40 router won't even come close to handling that many users. a commercial level router designed for many connections should be fine.

i had one of the ever popular lynksis wrt54g routers that worked fine until we hit about 7 devices and then it started having issues. i had to upgrade to a commercial grade cisco router for around $250 or so and then we were fine again and had no issues with 10+ concurrent users. was only a home network so it did not try to connect to more than that. i'm sure it would handle more but was never asked to.

just do your homework and ensure you get something designed for what you want it to do. last school i taught at went to all wifi and we had a router in each room that could connect 30 laptops easily and was rated for more than that.
 
The more users you have the more collisions in the wireless network. Wireless is half duplex and their is no central control. Pretty much the devices listen and if they hear no one they figure they can transmit. So this works ok with transmission between the router and end clients but you can have many situations where the end client can see the router traffic but not each other so they will both transmit over each other and the router will get 2 garbage signals but the end devices will only know the data was damaged. The more devices you have the more this can happen.

The total traffic amount also depend on the type of traffic. A video feed that sends packets at a constant rate actually causes much more issues that someone who send large burst of traffic in short periods of time. Both could have the same bits/sec rate when averaged over a couple minutes.

Most time the number business installation use is 10 "active" users....where what "active" means is not clearly defined.
 


Thank you.