It's not setup to do that right now, as you found. I'm not sure how invasive the changes may be to do this. On Jul 15, 2014, at 3:26 AM, Matteo <mbrancaleoni@voismart.it> wrote:
Hi,
the following applies to ftmod_sangoma_isdn.
Scenario: some pri isdn switches does not like exclusive channel selection, but needs the setup message to carry a preferred channel selection ie.
Adding this in freetdm (in setup message) and making it configurable is easy and an example patch is attached.
BUT!
If the remote switch changes the channel, we need to "move" the current freetdm channel to the one specified in the provisional response or setup ack.
According to q.931 is wrong to allocate a b channel before having confirmed the right one to use, but right now freetdm allocates it immediately. (maybe is worth changing that?)
So, I'm trying to understand all the stuff between freetdm and ftmod_sangoma_isdn in order to modify it and make the preferred b channel selection working.
Any hint ? Which is the best way to "swap" a freetdm channel or move to another? Is something the stack already allows or needs some major modifications?
mat<pri_exclusive.diff>_________________________________________________________________________