Re: Fwd: NetworkManager connection priority - same ssid ?

[José Queiroz <zekkerj gmail com>]

2011/1/10 mike cloaked <mike cloaked gmail com>

On Mon, Jan 10, 2011 at 4:19 PM, Franco Miceli
<fmiceli plan ceibal edu uy> wrote:
> Mike,
>
> I have been dealing with the AP algorithm selection a few months ago. The
> one that selects the best connection is NM. If you get the src you can see
> it in the file nm-device-wifi.c (for the wireless connections).
>
> The way it is implemented in nm 0.7 (which is the one I have been working
> on) is that NM will go through each favourite connection you have, and
> comparing them with the ones available from scan results. It does not
> prioritize on signal strength rather than timestamp. Which means if the one
> you last connected to is available it will connect to that one.
>
> I have been playing with the code in order to make that selection signal
> sensitive. In order to do that you need to get signal strength info. The
> method nm_ap_get_strength(ap) can help get such data. The thing is that not
> all wireless adapters report well signal strength, but if you trust yours,
> then you can make this mod.
>
> Hope I could help. If you need I can share the code I used.

Thanks Franco - I need to understand a few things - The version that
is current in F14 that I am running is
NetworkManager-0.8.1-10.git20100831.fc14.i686 and, as José Queiroz
mentions in his subsequent reply, there have been many important
changes since v7, although he does not reference a link to what those
changes have been in v0.8.

However, what I do not know is whether the selection of AP was made
signal sensitive in the implemented changes in 0.8 or not? Certainly
the last signal used appears to be the one selected when booting up
the machine after switching off previously, which would be a
reasonable "first option" for the starting choice, but then a
secondary criterion where a stronger signal that already has been
used, and is listed in the connections in NM, would be selected and
switched in instead.  Having such a two-stage selection would be what
would suit me (and many others) better than just going to the last one
used.

I wonder if José Queiroz would tell us if this is in fact what has
been implemented in 0.8 (or 0.81 or 0.82) or not? That would be very
helpful.  If this has been put into the code but has residual bugs
then presumably getting some data and putting in a bug report so that
developers could look at fixing it would be the way forward?

A nice level headed and fact based approach to this would be ideal.

I could swear that this was already discussed here, but the only reference I found was another message of mine.

In the lack of good references, I ran to my kubuntu box. I also have an ESS in my home.

My syslog shows several messages from wpa_supplicant about group rekeyings to one of the APs (the one that haves the strongest signal in the place I usually use my notebook).

In one moment, I see messages from the kernel about deauthenticating the first AP, and authenticating the second one. Around these messages, I see only messages from wpa_supplicant, even though NM debugging is enabled. So I concluded that this reassociation was ordered by wpa_supplicant, not by NM. But, I admit, this is only an empirical verification; I didn't checked any code to confirm this.