Re: Mobile Broadband : 2G/3G preference

[Dan Williams <dcbw redhat com>]

On Thu, 2009-02-05 at 19:51 +0000, Rick Jones wrote:
> Having just acquired a 3G Mobile Broadband USB modem, I'm running into
> a problem I didn't even know existed.
> 
> The device will work on 2G and 3G networks, and prefers a 3G
> connection when available. However, the 3G signal can be patchy and it
> will fall back to 2G if it's too weak. But when it does this switch it
> disconnects, and requires manual use of the NM applet to re-connect.
> 
> I was in a situation where the 3G signal was not reilable, but the 2G
> signal was good and steady, and I just wanted to stay connected on 2G.
> The problem was that from time to time the modem would decide the 3G
> signal was strong enough, drop the 2G connection and wait to be
> connected on 3G. This wouldn't last long and I'd loose the connection,
> and have to re-connect on 2G again. And so on ...
> 
> The proprietary connection gadget for Windows that comes with the
> modem allows you to select a preference - 2G, 3G, or neither, so the
> modem can be programmed to do this (I believe it's done with a
> standard AT command). I assume the same applies to most if not all 3G
> modems, and it would be extremely nice (not to say essential) to be
> able to do this in NM.
> 
> Using "connect automatically" in the connection config helps with
> re-connects, but doesn't stop unnecessary breaks.
> 
> (Something else the Windows gadget does is support sending and
> receiving SMS, which is quite cool. Is it possible for another app to
> access the modem to do this even while it's being managed by NM? -
> it's obviously not really within the scope of NM itself)
> 
> Any thoughts?

We plan on making this available when ModemManager integration is
committed.  Unfortunately, every manufacturer implements the 2G/3G and
Roaming preferences using different commands, thus we have to
special-case many modems, and this wasn't possible until ModemManager.

Dan