wpa_supplicant limitation with a large number of APs.

Jouni Malinen jkmaline
Thu Feb 24 22:25:56 PST 2005

On Fri, Feb 25, 2005 at 01:12:48PM +0800, YenJung Chang wrote:

> I said that the memory size of scanning result is 4096 is bcz the
> variable "res_buf_len" in funcion wpa_driver_wext_get_scan_results in
> driver_wext.c
> (wpa_supplicant 0.3.8) is assigned IW_SCAN_MAX_DATA (4096).

That is the initial value, but it will be incremented up to 65536 bytes
if the driver returns E2BIG.

> And the max got number of AP is about 20 is the number I most saw when 
> wpa_supplicant ran.

Which driver are you using? I think I have seen much higher numbers, but
this requires that the driver supports long scan results. Do you see
more APs if you do a scan manually with 'iwlist <interface> scan'? The
current hard limit on the wpa_supplicant side (SCAN_AP_LIMIT) is set to

> I tried ap_scan=2 without security. Unfortunately, it failed.
> Is there any restrication on ap_scan=2 ?

Yes, driver needs to support it and not all do.

Jouni Malinen                                            PGP id EFC895FA

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