[pjsip] Handling ACK manually (was Re: 3PCC transfer implementation)

Benny Prijono bennylp at pjsip.org
Mon Nov 26 22:57:52 EST 2007

Dear all,

I've just committed a patch to allow application to handle sending 
ACK manually. Please see http://www.pjsip.org/trac/ticket/416, and 
for more information, please see the doxygen comments on the new 



Amit Sharma wrote:
> I  guess there are also issues once the call transfer is completed.
> Once the 3pcc transfer is completed, most of the signalling would need 
> to be end to end (between the endpoints) with the controller passing 
> requests (and responses) from leg to the other. This requires that there 
> is no local handling of reinvites,updates etc. Would this not require 
> exposing incoming requests also to the application? I think a 3pcc call 
> would need a different state machine for the handling of requests.
>  Can we not  have a pjsip_inv_set_3pcc_mode(inv_session, peerdialog) 
>  like api that can be invoked by the application on a invite session to 
> change how subsequent requests are handled in the session . The invite 
> session could define a different invite state handler for 3pcc scenario 
> which the session uses once the 3pcc mode is set    
> e.g
> void (*thirdpcc_inv_state_handler[])( pjsip_inv_session *inv, 
> pjsip_event *e) =
> {
> &thirdpcc_on_inv_state_null,
> &thirdpcc_on_inv_state_calling,
> &thirdpcc_on_inv_state_incoming,
> &thirdpcc_on_inv_state_early,
> &thirdpcc_on_inv_state_connecting,
> &thirdpcc_on_inv_state_confirmed,
> &thirdpcc_on_inv_state_disconnected,
> };
>  This is probably close to writing a 3pcc module. The reason is that I 
> am not sure we can reuse the existing invite session to support both 
> 3pcc and normal scenarios in the application.
> -Amit

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