Re: WiFi: Problem with Entreprise networks (with multiple routers)

[Dan Williams <dcbw redhat com>]

On Tue, 2013-10-22 at 13:51 +0200, Matthieu Baerts wrote:
> On lun, 2013-10-14 at 19:49 +0200, Matthieu Baerts wrote:
> > On lun, 2013-10-14 at 12:20 -0500, Dan Williams wrote:
> > > On Mon, 2013-10-14 at 18:39 +0200, Matthieu Baerts wrote:
> > > > Hello Dan and thank you for this answer,
> > > >
> > > > On Mon, 2013-10-14 at 09:41 -0500, Dan Williams wrote:
> > > > > This problem is most definitely a supplicant issue.  The supplicant
> > > > > roams too aggressively, even if the currently associated access point
> > > > > has a very good signal.  We've patched that in Fedora, but as you
> > > > > indicate, your kernel wifi driver is also not working correctly when
> > > > > reporting signal strength.
> > > >
> > > > Thank you for these details!
> > > > Do you know if it's possible to configure wpa_supplicant (via NM or not)
> > > > to be less aggressive but without having to patch it? (or to force it to
> > > > not switch between access points?).
> > > >
> > > > I know that we can force wpa_supplication to try to connect to a
> > > > specific access point (by using the mac address) but it's not what I
> > > > want: I don't want to change the settings each time I want to connect to
> > > > a different access point of this network.
> > >
> > > Correct, you want to keep roaming enabled, and that's not possible
> > > (obviously) when locking to a specific access point.  There a few things
> > > that will make this better:
> > >
> > > 1) Apply the following patch to your wpa_supplicant, which will make the
> > > problem much better but
> > > http://pkgs.fedoraproject.org/cgit/wpa_supplicant.git/tree/rh837402-less-aggressive-roaming.patch
> > >
> > > 2) Apply the following commit to your NetworkManager packages, which
> > > requests that the supplicant scan for roaming a little less often:
> > >
> > > http://cgit.freedesktop.org/NetworkManager/NetworkManager/commit/?id=dd9cf657ef1f9d5909dad2eb697098715325fecf
> > >
> > > 3) Wait for some upstream changes to the supplicant, which will include
> > > *some* form of the above patch, as well as one I posted upstream to
> > > request the supplicant not to roam as a result of an information-only
> > > scan that NetworkManager periodically does.
> >
> > Thank you for these patches, I'll have a look asap! (but I'm not sure
> > I'll be able to test it soon)
>
> Thank you, I confirm that it's much better with these patches!
>
> > > Obviously all these fixes depend on the kernel driver also reporting the
> > > signal strength correctly...
> >
> > Yes...
>
> Due to this problem with my drivers, I'm using this setting:
>   bgscan = simple:30:-65:9000
>
> But do you have any idea how I can use this setting without patching
> each new version of NM?

NM uses -65 already in NetworkManager 0.9.8.4 and later.  Which drivers
are you using again?  If they are in-tree ones, it would be much easier
to get them fixed.  That combined with the changes for periodic scanning
not causing a roam (which was just applied upstream to wpa_supplicant)
should help immensely.

Dan