Min-Client-Strength

A WLAN installation at a location with a really large potential number of clients (e.g., a football stadium) has considerable throughput problems. In this type of scenario, a possible cause is a large percentage of overhead due to remote stations with a weak connection. If one of these stations is registered (associated), the access point can only send data to this station with a relatively low physical bit-rate – possibly with several repetitions per packet. Not only does this result in a weak connection for the user, it also places a load on the medium to the detriment of clients with stronger connections, which would otherwise make more effective use of the available bandwidth. It should be noted that unregistered remote stations can also negatively impact the throughput of the cell when attempting to find a network. Probe requests (search packets) of such clients must be directly and specifically answered by the AP after reception, e.g., they will be repeated until the client has confirmed receipt or the maximum number of repetitions is reached. The effect is worsened by the fact that these response packets are WLAN management packets, which are usually transmitted at the lowest available fixed bit rate as supported by the AP.

Although there is no way that an AP can prevent clients from sending probe requests, it can ignore them or simply not respond to them if they fall below a certain signal strength.

A configured Min-Client-Strength functions as follows:

• If a probe request with an appropriate SSID or a placeholder SSID is received, a response is only sent if it has at least the minimum signal strength. If not, it is silently discarded.
• If an authentication or registration request is received, which is below the configured signal strength, it will be rejected. Please note that this situation is rare, since the probe requests of such clients usually go unanswered anyway, and a client can only have found this AP using a passive search of its radio beacon.

This value is specified as a percentage. This specifies the ratio of the signal and noise levels (SNR). A percentage value of 100% means an SNR of 64 dB, smaller percentage values are correspondingly lower. The default value is 0, e.g., no clients are ignored.