High density AP Deployment minimum data rate/single strength

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We are in the process of deploying wifi in public areas across the city.
At some public areas we get on average 200 to 300 people walking past a single AP. 
The users might not be using the wifi service but their client devices still automatically associates to the AP, resulting in each AP having +- a 100 associated clients at any one time = poor service.
How do we prevent clients with a -75/-80 dbm signal strength from associating with the AP? 
Or do we restrict the number of users per AP?
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Andre Brits Kannemeyer

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Posted 4 years ago

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Hartmut Sachse

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Hello Andre,

there are several features you can use to load balance the clients between access points in range of the clients:

1. Band steering push clients with 802.11a/n(/ac) to this ap radio module instead of establishing a client connection at the 802.11b/g/n radio module

2. Enable load sharing of clients between access points (possible at site configuration i think) for better density balance

Other reasons for poor wireless performance resulting in sharing the available channels with other access point around the location. In the 2,4 GHz frequency space high channel contention (co-channel contention) is a big problem. 5 GHz is much better, because you have more channels available, but not every mobile support it.

Another recommended practice is create smaller cell sizes and use more access points. In some cases is make sense to only use 20 MHz channels on the 802.11a/n radios.

Best Regards
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Ronald Dvorak, Embassador

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The only thing that you'd do is to increase the minimum basic rate so clients with a low RSSI couldn't connect to the AP.

Also please keep in mind that the controller only supports a certain number of clients at any time i.e. C5210 supports 8192 clients.
So in your example that would result in 4x WLAN Controller C5210.
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Hartmut Sachse

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Really good idea.

The client limit of the C5120 in mind, keep me asking the question how many controllers did Extreme use in there reference station high density deployment? Around 9 controllers for the approximately 70.000 users i think.  
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Simon Vosper

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How do you know the numbers of associated clients is the cause of the poor performance?

A number of attached clients should not degrade performance too much. Its the bandwidth and airtime they take up when they are sending or receiving data that would cause a problem.

In certain conditions it would not be unreasonable for an AP to support 100 clients that are concurrently transmitting data and still provide the client/application with the throughput it needs to function, especially if that's just web traffic.
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Raffi, Employee

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