Re: Networking and Internet connection sharing using a USB mobile (Cellular) broadband modem.

[Dan Williams <dcbw redhat com>]

On Tue, 2009-10-06 at 12:01 +0100, Neill Rutherford wrote:
> This is a request for guidance. I am new to Linux.
> 
> Internet -> Option ICON 225 -> HP 5271 Pavillon Laptop =>DLink 660
> PCMCIA Card. =>LinkSys Wrk54G  
>                                                          (FireStarter
> with ICS)                                                      WAN
> Accessport
> 
> Once connected the network is stable.
> 
> The problem is at boot up. When  the PC is shutdown (requires manual
> Power Off). The PC will not then reboot with the Network as shown
> above running correctly. The eth0 connection connects but not the hso0
> connection. 

Mobile broadband auto connection stuff needs some work.  It also
requires a bit of code in NM to ensure that connection retries happen,
for all connection types including wifi and ethernet, not just 3G.
We'll work on that.

> Sometimes a simple 
> 
> sudo /etc/init.d/NetworkManager force-reload 
> 
> will restart the network but on other occasion as today the USB Dongle
> has to be unplugged first. Usually once replugged and the USB stack
> has reconfigured then connection can be obtained.
> 
> Visible notification from the NetworkManger in terms of what is seen
> on the Taskbar are;
>       * Twin stacked PCs

Means ethernet is connected

>       * Twin stacked PCs with red X

No connection

>       * Twin Grey Dots and stationary "Spinning Comet"
>       * Twin Grey Dots and "Spinning Comet"
>     Either
>                       * Twin Dots one green and  "Spinning Comet"
>                       * Twin Green Dots and  "Spinning Comet"
>                       * Radio Tower (success)
>     or 
>                       * Twin stacked PCs (failure)
> 
> Why is this important it is simple to fix as stated above, well I am
> planning on replacing my gateway PC with a Linksys NSLU2
> (http://www.nslu2-linux.org/) device and would really just like it to
> work without having to connect to the NSLU2.
> 
> If once connected, I then reboot the PC (No hard power off), it does
> so and the Windows PC have access to the Internet. I do not have to
> log in to the Xubuntu 9.04 PC which is of course what I want. I do not
> however to intent to or wish my gateway to be powered continuously or
> indeed continuously connected to the Internet.
> 
> I hope this adequately describes my problem.
> 
> Is there some command I can place in my gateway PC's startup script
> that will perform the same as unplugging the ICON 225?

Not entirely sure about that one; you probably want reconnection at the
USB layer, not at the NM or serial layer.  You want to completely
re-initialize the modem and get a replug.  I bet there is something
in /sys that can be made to do that for a USB device since I know there
are lower-level operations for it.

In short, we do need to do some work in NetworkManager to make reconnect
and initial connect more reliable.  But there's also probably ways you
can work around that for now with the USB layer.

Dan