Re: Two WLANs with the same SSID but different connection names

[Dan Williams <dcbw redhat com>]

On Mon, 2012-09-24 at 22:32 +0200, Alexander Karlstad wrote:
> Den 20. sep. 2012 19:23, skrev Dan Williams:
> > On Wed, 2012-09-19 at 16:47 +0200, Alexander Karlstad wrote:
> >> Den 19. sep. 2012 14:23, skrev Marius Kotsbak:
> >>> Does the same happen if you remove autoconnect for both of them? Maybe
> >>> NM always autoconnect to the first one.
> >>
> >> Turning off autoconnect to both networks actually did the trick. Still,
> >> that means the autoconnect option overrides my manual selection. Not cool.
> >
> > NM will autoconnect to a network that (a) has autoconnect selected, (b)
> > shows up in a scan result, and (c) matches the connection attributes.
> >
> > So, if you have two networks with the same SSID and both use WPA/WPA2,
> > then NM will select the *last used* connection.  Because, for all NM
> > knows (and a lot of other wifi managers too) they are the same network
> > because they use the same SSID and same security type.  It's pretty bad
> > network planning to use the same SSID for actually different networks.
> 
> But this is not two different networks per se. The Eduroam-network is 
> used all over the world at different educational institutions. The only 
> difference here is that I have a user account at two different colleges, 
> and sometimes you just get basic access when using a username/password 
> from a different college. That's why I want to be able to use the two 
> separatley.
> 
> The workaround was disabling autoconnect for this network, but it feels 
> very much like a bug when I manually select which network I want to 
> connect to doesn't work. Even though DBUS tells me it's using the right 
> cridentials.

Yes, it would certainly be a bug if you selected a connection from the
menu and NM did not activate the connection you selected.  However, that
is actually a UI issue; the UI is responsible for displaying the
connections and assigning them to a specific network name.  We do
actually have code in the applet that shows a sub-menu for an SSID when
there is more than one connection that applies to that SSID+security.
IE, if there is "MySSID" using WEP and "MySSID" using WPA, the nm-applet
will break that out into two separate items in the menu.  But if there
are two different connections for "MySSID" with WPA, then a sub-menu
should be shown.  Obviously autoconnect will still need to be disabled,
since the networks look *exactly the same* from the laptop's point of
view (no way to distinguish, unless say one uses WPA1 and the other
WPA2), but it should allow you to select the specific connection you
want to use.  Otherwise it would be a bug.

Obviously this all applies to nm-applet; other UIs (KDE, Gnome Shell,
etc) may work differently.

(One thing we could fix up: since we keep a list of the BSSIDs that
we've successfully connected to, if we see that BSSID in a scan list, we
could auto-pick the right connection if two connections may apply.  This
isn't foolproof, but is something we could do to improve the
experience.)

Dan