wpa_supplicant and roaming

[Lohmann, Peter]

In a WLAN with mobile devices actively roaming between the wireless footprints of multiple APs (same SSID),
the wpa_supplicant will disassociate with an AP when it has a very weak signal, then associate/authenticate with 
an AP with a stronger signal.  The problem is that it will hold on to an AP with a very low SNR level, even if 
it is on top of an AP with a more optimal SNR level.  It will not disassociate until the signal is almost 
unusable.

Is there a way to make the wpa_supplicant more aggressively switch APs within the same network (SSID) when a
better signal is detected?  Ideally, this would be controlled via a threshold.  You wouldn't want to be
constantly switching APs.

There is a Debian-based tool (wpa-roam) that *seems* to be used for multi-network roaming.

If this feature does not exist in the wpa_supplicant, I might try to implement it and provide a patch, if this
is useful to others.

Here is a wpa.conf for this:

ctrl_interface=/var/run/wpa_supplicant
ap_scan=2
network={
  ssid="campus-library"
  key_mgmt=WPA-PSK
  pairwise=TKIP
  psk=3ca0e76da317c94efa43893267a7065ed96a31c2b6c9e4ae72ecdce1ba5de407
  proto=WPA
}


Thanks,

     -- Peter