Probe requests are 802.11 management frames sent by clients to request information about the capabilities of SSIDs. By default AP forward acknowledged probe requests to the WLC for processing. Acknowledged probe requests are probe requests for SSIDs that are supported by the AP. If desired you can configure access points to forward both acknowledged and unacknowledged probe requests to the WLC. The WLC can use the information from unacknowledged probe requests to improve the location accuracy.

You can configure this via WLC CLI as shown in the below.

1. To enable or disable the filtering of probe requests forward from an AP to the WLC (by default the feature is enabled)

config advanced probe filter {enable|disable}

2. To limit the number of probe requests sent to  WLC per client per AP radio in a given interval you can use following CLI command

config advanced probe limit <num_probes> <interval>

<num_probes> is the number of probe requests ( valid range 1-100) forward to the WLC per client per AP radio in a given interval.
<interval> is the probe limit interval (valid range is 100-10000 ms)

Default value is 2 probe requests for 500ms. You can verify your configuration by “show advanced probe” CLI command.

(4402-a) >show advanced probe 
Probe request filtering..........................  Enabled
Probes fwd to controller per client per radio....  2
Probe request rate-limiting interval.............  500 msec
Aggregate Probe request interval.................  500 msec

Here is a configuration example of this feature.

(4402-a) >config advanced probe ?
filter         Configures filtering of probe requests forwarded from APs to the controller.
limit          Limit number of probes sent to controller per AP slot per client in a given interval.

(4402-a) >config advanced probe filter ?           
disable        Forwards probe requests from all clients to the controller
enable         Forwards only acknowledged probe requests to the controller

(4402-a) >config advanced probe filter disable
(4402-a) >config advanced probe limit 5 1000

(4402-a) >show advanced probe 
Probe request filtering..........................  Disabled
Probes fwd to controller per client per radio....  5
Probe request rate-limiting interval.............  1000 msec
Aggregate Probe request interval.................  500 msec

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