Re: Roaming network selection with MB

[Dan Williams <dcbw redhat com>]

On Wed, 2009-06-10 at 13:07 +0100, Rick Jones wrote:
> I ran into a problem recently trying to use my mobile broadband modem
> in France, roaming from the UK.
> 
> I discovered that my carrier only has roaming agreements with 2 of the
> 3 French networks, but this doesn't stop the modem locking onto the
> wireless signal of the unsupported one (it's not barred in the SIM).
> This requires manual selection of the network before attempting to
> make a connection. Their Windows connection gadget supports this - is
> this a feature that will be available in Modem Manager?

The "Network" field of the 3G connection editor window for your
connection will accept an MCC/MNC value like "31026" which identifies a
specific network to register with, and no others.  You can use that to
lock to the network you want, but then you can't roam.

GSM doesn't roam as well as CDMA in this case, because CDMA modems
include a list internally in the card that says what providers you can
roam with, then most devices have a "roam on/off" switch in the UI.

With GSM, you don't get any granularity, you either specify a network to
register with manually, or you let the card roam to anything it wants
to.  With modem-manager, we could, if manual registration fails, do a
scan (which can take up to 2 or 3 minutes unfortunately depending on how
many bands your modem supports, anywhere from 2 to 8).  Then we could
pick a provider out of the scan that you've explicitly allowed roaming
to, or something like that.

Dan