Re: 3G multiple PDP context support

[Marcel Holtmann <marcel holtmann org>]

Hi Joe,

> If answered already sorry for the general question  -  searched
> archives and did not see much.
>
> I am wondering if there is support (on any 3G UMTS device) for
> simultaneous multiple-PDP contexts in NetworkManager.
>
> We have Qualcomm-based and other vendor commercial phones and dongles
> which support multiple-PDP context but no way to have active data over
> multiple contexts (3 simultaneous is desired).

with off the shelf USB dongles, I have not seen this working properly
actually. The only device I know of that can do this is MBM if you use
the high-speed channel for one and PPP for the other one.

Of course with cellphone modems like the ISI from Nokia or Infineon and
even ST-Ericsson the multiple PDP context setup is possible.

The biggest problem here is that if the dongles are bound to be using
PPP, then normally no more than one PPP session is support. And thus
only one active PDP context at a time. Main reason is that the resources
inside the modem firmware is pretty much limited and PPP is a damn waste
from resources point of view.

If they are not using PPP, then normally they only give you one high
speed Ethernet or point-to-point IP interface. That is not really enough
to get you to the three you want.

Also I don't really know if Modem Manager is designed for handling more
than one PDP context per modem.

Regards

Marcel