Re: [GnomeMeeting-devel-list] Ekiga with notebook

[Craig Southeren <craigs postincrement com>]

On Sat, 04 Feb 2006 14:25:45 +0100
Hannes Ebner <dev stdout at> wrote:

> Hi,
> 
> Damien Sandras wrote:
> > - if your IP change, it will update all accounts
> 
> the interface is also interesting.
> 
> At home I use eth0, on the way it is either wlan0 or ppp0. I have to
> change this setting everytime I start up Ekiga or resume the laptop.
> That's pretty annoying, because I also have to manually re-register all
> accounts after changing the interface.

I am going to try and describe the problem here

a) When the laptop goes into standby mode, the network interface is
taken down and so network communications stops. 

b) During the time the laptop is in standby, the gatekeeper or registrar
will detect that the machine is offline because it is not responding and
because it does undate it's registration. Therefore, it will become
unregistered. This is correct - if the machine is in stand-by then it
cannot receive calls so it *is* offline.

c) When the laptop is resumed, the network interface interface is
restarted. I would expect that the machine would get the same IP address
as previously, and Ekiga simply re-registers and continues as normal.

Obviously this is not happening :)

Not being an expert in the details of Linux laptop networking, I don't
know exactly what the problem is, but I can guess it is one of the
following:

1) The network interface is actually removed from the the system during
standby period. This means that after resume, Ekiga detects that the
network interface has disappeared and so closes that network transport.
But when the interface comes back online, Ekiga does not see this and so
stays unregistered.

2) The network interface is not removed, but comes back with a different
IP address. Ekiga does not see this new address and so is trying to
register using the old address on the new interface which will not work.

> Would it be possible to include functionality (perhaps bound to a
> checkbox in the preferences) to let Ekiga always listen on the interface
> from which the default gateway is reached?

That's not a very easy thing to detect, given the wide range of network
configurations and operating systems. It would require getting the
address of the default gateway and then applying the local routing rules
to get the interface. And then redoing it every time the default gateway
or the routing rules are changed.

I think the solution to the problem is to add support for the addition
and removal of network interfaces. There are signals/events for this
kind of thing in both Linux and Windows that we could hook into that
should then be used by the OPAL/OpenH323 to stack to trigger automatic
network reconfiguration. As a side note, we should do the same for the
addition/removal of sound and video devices as well.

   Craig

-----------------------------------------------------------------------
 Craig Southeren          Post Increment ? VoIP Consulting and Software
 craigs postincrement com au                   www.postincrement.com.au

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