Fwd: NetworkManager connection priority - same ssid ?

[mike cloaked <mike cloaked gmail com>]

---------- Forwarded message ----------
From: mike cloaked <mike cloaked gmail com>
Date: 2011/1/9
Subject: Re: NetworkManager connection priority - same ssid ?
To: José Queiroz <zekkerj gmail com>


2011/1/9 José Queiroz <zekkerj gmail com>:

> AFAIK, the selection of which AP to connect, in a ESSID, is done by
> "wpa_supplicant", not by NM.

OK - accepted but NM is setting up the wpa_supplicant configs from the
gnome desktop.

>> What I would like is that in this instance the connection is made to
>> that AP that is giving the strongest signal at the laptop but it does
>> not always do this.
>>
>
> That's exactly the criterium used by wpa_supplicant to choose which AP to
> connect: strongest signal.
>
> But if there's some problem with the strongest signal (e.g. authentication
> timeout), it will try the other APs available.

In my latest test I am using Fedora F14 and set the laptop to connect
to the home LAN via G wireless with its primary AP using WPA/AES
encryption, as well as a range extender set to the *same* SSID with
the same encryption but on a different level in the house.

The laptop was initially set to use NM with correct authentication to
the primary AP and was stable.  When moved to the vicinity of the
wireless range extender as the nearest and strongest signal (in fact 2
feet from the antenna!) then it connected fine and began showing the
nearby strong signal for several seconds, and then showed the primary
signal for a few seconds (now weaker as it was further away but still
usable) and then kept switching between the two every 5 to 10 seconds.

The only way I could make it sit in a stable condition was to put in
the MAC address as an additional constraint (in the NM connection gui)
for the nearest strong signal (being the range extender), and then
define a second connection (using NetworkManager) for the original AP
using its *different* MAC address with the same SSID and encryption
details.  Then when I asked NM to go to the near strong signal it
remains stable and does not continuously hunt between the two.
However moving the laptop to be near the primary means requiring it to
be manually selected to the new strong signal since it is a second
previously connected wireless source - this means that this is not
seamless in moving the laptop between the two APs.

I guess the intention was that wpa_supplicant was supposed to work in
a seamless way under these circumstances but my situation shows that
the system does not behave in the intended manner - which is why I am
reporting this to this list.

By the way in this case both signals are virtually noise free,. and
indeed there are no neighbours using the same channels - (I checked
over a period doing a wireless site survey both before the test and
during the test)

The hunting behaviour seemed to occur when the two signals had
different ssid as well - but only when I defined the two connections
with specific MAC did I get stability - that presumably should not be
necessary?

I guess many users will not be hooking up to multiple APs using the
same ssid and encryption but NM and wpa_supplicant should handle this
in a transparent manner and not need special configuration.

I would be interested to hear if anyone else has had a similar problem?

--
mike c



-- 
mike c