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Global Call IP Technology Guide — November 2007 91
Dialogic Corporation
IP Call Scenarios
Figure 33. SIP Call Transfer Failure - Party B Rejects Call Transfer
3.3.6.2 No Response From Party B
Figure 34 illustrates a scenario in which the Transferee (party B) does not respond to the REFER,
causing the T3 timer at the party A (configured as 20 seconds) to expire. After the timeout, the
Transferor application receives the GCEV_INVOKE_XFER_FAIL termination event. The original
primary call is left connected and in the GCST_CONNECTED state from the perspective of both
party A and party B.
Figure 34. SIP Call Transfer Failure - No Response from Party B
Pre condition: Primary call between A and B is connected (not shown).
A
(Transferring,
Transferor)
App
A
(Transferring,
Transferor)
IP CCLib
B
(Transferred,
Transferee)
IP CCLib
C
(Transferred To,
Transfer Target)
App
C
(Transferred To,
Transfer Target)
IP CCLib
B
(Transferred,
Transferee)
App
Post condition: Parties A and B remain connected.
Default reject reason is
603 decline if not
specified by application
gc_InvokeXfer
(CRNp)
REFER
GCEV_REQ_
XFER(CRNp)
gc_RejectXfer(CRNp,
IPEC_SIPReason
Status480Temporarily
Unavailable)
GCEV_REJ_
XFER(CRNp)
480 Temporarily Unavailable
GCEV_INVOKE_XFER_
REJ(CRNp)
Cause = IPEC_SIPReasonStatus480TemporarilyUnavailable
Pre condition: Primary call between A and B is connected (not shown).
A
(Transferring,
Transferor)
App
A
(Transferring,
Transferor)
IP CCLib
B
(Transferred,
Transferee)
IP CCLib
C
(Transferred To,
Transfer Target)
App
C
(Transferred To,
Transfer Target)
IP CCLib
B
(Transferred,
Transferee)
App
Post condition: Parties A and B remain connected.
gc_InvokeXfer
(CRNp)
REFER
GCEV_REQ_
XFER(CRNp)
GCEV_INVOKE_
XFER_FAIL(CRNp)
Timeout/
network error
(No response from
B application)
Cause = IPEC_InternalReasonNoResponse