Filter
Top Products
82 Dialogic
®
Global Call IP Technology Guide — November 2007
Dialogic Corporation
IP Call Scenarios
Figure 28. Successful SIP Unattended Call Transfer, Party A Clears Primary Call prior to
Transfer Completion
Figure 29 illustrates a scenario in which party B drops the primary call with party A after accepting
the transfer request and issuing INVITE to party C, but before receiving any response from party C.
In this scenario, party B does notify party A, but this notification only signifies that party B has
acted on the transfer request and not that the transfer has actually completed.
A
(Transferring,
Transferor)
App
A
(Transferring,
Transferor)
IP CCLib
B
(Transferred,
Transferee)
App
B
(Transferred,
Transferee)
IP CCLib
C
(Transferred To,
Transfer Target)
App
C
(Transferred To,
Transfer Target)
IP CCLib
Primary call is dropped and released.
Transferred call is connected.
gc_DropCall(CRNp)
GCEV_DROPCALL
(CRNp)
gc_ReleaseCallEx
(CRNp)
GCEV_
RELEASECALL
(CRNp)
GCEV_REQ_
XFER(CRNp)
Precondition: Primary call between A and B is connected (not shown).
GCEV_DIALING
(CRNt)
GCEV_DROPCALL
(CRNp)
gc_ReleaseCallEx
(CRNp)
GCEV_RELEASECALL
(CRNp)
202 Accepted
GCEV_ACCEPT_
XFER(CRNp)
GCEV_
INVOKE_XFER_
ACCEPTED(CRNp)
NOTIFY(100 Trying)
Subscription-State=active; expires=300
BYE
200 OK
200 OK
GCEV_XFER_FAIL
(CRNp)
REFER
gc_InvokeXfer
(CRNp)
INVITE
GCEV_ANSWERED
(CRNt)
gc_AnswerCall(CRNt)
ACK
200 OK
gc_DropCall(CRNp)
GCEV_CONNECTED
(CRNt)
Post Condition:
GCEV_OFFERED
(CRNt)
Cause = IPEC_SIPReasonStatusBYE
gc_MakeCall(CRNt)
No primary CRN
available
GCEV_
DISCONNECTED
(CRNp)
Unlike the H450.2 CCLIB
implementation, Party A will not
receive invoke xfer termination
event if Party A drops primary call
early because there is no way
of knowing if invoke transfer
succeeds or fails.
gc_AcceptXfer(CRNp)