Re: No inter-AP Roaming?

[Derek Atkins <warlord MIT EDU>]

Quoting Dan Williams <dcbw redhat com>:

> On Tue, 2007-12-04 at 15:31 -0500, Derek Atkins wrote:
> > I'm sitting at the IETF, connected to the 802.11 network..
> > But as I wander from room to room, NM doesn't roam.  It wont
> > jump from one AP to another as I move around the conference
> > facility.  I'll get to my new room and find that I no longer
> > have any network and then have to wait for a full connection
> > sequence.
> >
> > What gives?  I certainly don't have this problem if I just
> > let the driver/hardware roam on its own.
>
> Well, NM doesn't control roaming at all, wpa_supplicant and the driver
> do.  Sometimes wpa_supplicant will push the BSSID down to the driver
> when connecting (not entirely sure when that is) and if the driver
> actually follows WEXT (which lots don't) that would cause the driver to
> lock to that single BSSID and not switch.  That bit is highly driver
> dependent.  It looks like wpa_supplicant will only do this when it has
> previously timed out authentication with the station but tries again
> (like it should).  It then passes the BSSID down to the association code
> which tries to lock the card to that BSSID specifically.

Interesting.

I'm using the iwl3945 driver.  I DO see some authentication timeouts,
which is really weird.. Sometimes to the point where it wont even
successfully authenticate to the card at all and I have to reset.
Very frustrating.

How do I tell whether wpa_supplicant is locking me to a particular
BSSID, and how do I undo that once it's done?

> Dan

-derek

Strangely, it DID just roam as I went from my lunch meeting to
my first after lunch session.  But it's still annoying that it
can drop the session so easily/quickly whereas non-NM will gladly
re-acquire the association as I move between areas, even if I hit
an area of no coverage.

--
      Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
      Member, MIT Student Information Processing Board  (SIPB)
      URL: http://web.mit.edu/warlord/    PP-ASEL-IA     N1NWH
      warlord MIT EDU                        PGP key available