wpa_supplicant roaming question
janusz.dziedzic at gmail.com
Wed Aug 31 04:21:34 EDT 2011
2011/8/30 Matt Causey <matt.causey at gmail.com>:
> I have a question about how scans are meant to be triggered with
> wpa_supplicant, mac80211, and family. At my site, we have a fleet of
> small devices that run the Atheros ar928x wireless cards. We use
> EAP-TLS on Motorolla WLAN infrastructure. We're running linux
> 2.6.38-2 with no vendor patches. Our wpa_supplicant version is 0.7.3.
> In our situation, we'll have a client adjacent to 2 or 3 BSSIDs
> broadcasting the same ESSID, and the client moves about from time to
> time. What I am seeing is that the client will sit on a -70 access
> point, without roaming, for hours even in the presence of another
> access point that registers as -50. However, if I do something to
> manually trigger a scan, the device will suddenly roam to the more
> favorable access point.
> For example, I can do 'iwlist scan', or HUP the supplicant. iwlist I
> am sure causes the driver to generate a new set of scan results -
> which the supplicant picks up and uses. HUP of the supplicant causes
> the supplicant to call wpa_supplicant_req_scan(), and then roam as a
> result of the new scan data. This leaves me thinking that the roaming
> algorithm is working great, it's just that the background scanning is
> not working as I would expect...
> So I read about bgscan here:
> It looks like what I want - to configure the supplicant to scan
> periodically. However I have it enabled and I don't ever see it kick
> in. Any ideas why?
> Here is our supplicant config:
> freq_list=<a list of the frequencies that we use>
> private_key_passwd="<noober mic nooberson>"
> If there is other info I can provide please let me know!
Did you enable this CONFIG_BGSCAN_SIMPLE=y in wpa_supplicant/.config
file before compilation?
We are using bgscan simple and learn and don't have such problems.
If still an issue:
Run wpa_supplicant with -ddd option. After that you should get debug
messages connected with bgscan_simple.
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