[OpenSIPS-Users] [NEW] exchanging info between dialogs

Bogdan-Andrei Iancu bogdan at voice-system.ro
Wed Apr 28 17:46:50 CEST 2010


just added to the dialog module a new function that allow you to 
exchange data between dialogs - mainly to extract data from a different 
ongoing dialog.

Such functionality is vital in complex scenarios (PBX related) like 
attended call transfer - in such cases you may want to route a new call 
based on information of existing dialogs.

Real case example:

    OpenSIPS is doing dispatching over a set of Asterisk boxes (which 
act as SIP servers).
    A calls B and the call is established (by dispatching from OpenSIPS) 
via A1 Asterisk server
    A wants to transfer B to a new party C, so A makes a new call to C 
-> this call must end on A1 also, without going via dispatcher in openSIPS.
    So, when A calls C, OpenSIPS will check if A has an already existing 
call and if so, it will send the new call to the same Asterisk box as 
the existing call.

In such a case, for each call, you need to attached to the call (as 
dialog variables) the callee, caller and the Asterisk box . When a new 
call is coming, you check if the new caller is already involved in a 
call and if so, fetch the value of the proxy in order to send to the 
same box.

For more about the technical details of the function, see


Bogdan-Andrei Iancu

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