[Asterisk-Dev] codecrenegotiation andfax [was:codec negotiationissue]

[Kevin P. Fleming]

Florian Overkamp wrote:

> Jesse has this stuff implemented in iaxclient to some extent, but his
> question is: what kind of signalling can we send to an asterisk box that
> will give the desired behaviour ?

My experience to date has been only with SIP, where renegotiation of 
codecs is already supported. I spoke with Steve Kann briefly on IRC a 
few weeks ago and he seemed to think that doing renegotiation in IAX2 
would be easy to add.

> BTW, in your other post you are stating you estimate a timeframe of 30 days
> to get this a bit further in the works. It would be nice if we can agree on
> some basic API to allow access to that functionality from a monitoring
> environment, which is what Jesse uses in his research to automatically
> switch based on the network behaviour. If the design is clear enough, Jesse
> and I will work on integrating his work into Asterisk where possible.

My work has been focused on making Asterisk internals remember what 
codecs the peers can support, and initiating renegotiation when needed 
as channels are bridged. Initially my efforts will be focused on making 
chan_sip react to these requests and renegotiate with its peer(s), but 
any help available in extending this to IAX2 would be welcome.

As far as renegotiation initiated from the IAX2 peer end (not Asterisk), 
that will require someone who knows IAX2 better than I do to determine 
what will be needed to indicate that negotiation is wanted.