Filter
Top Products
Dialogic
®
Global Call IP Technology Guide — November 2007 65
Dialogic Corporation
IP Call Scenarios
3.2.4.5 Party C is Busy When Transfer Attempted
The transferred-to endpoint (party C) may also be busy at the time of transfer (unknown to the
transferring endpoint). As indicated in Figure 19, this would result in a Release Complete message
with Q.931 Cause 17, User Busy, being returned to the transferred endpoint (party B) indicated to
its application via a GCEV_DISCONNECTED event with a cause of GCRV_BUSY. The
transferred endpoint (party B) returns a ctInitiate.ReturnError APDU to the transferring endpoint to
indicate the transfer failure and in turn must drop the transferred call attempt. As a result, the
GCEV_INVOKE_XFER_FAIL termination event is received at transferring endpoint (party A) and
the original primary call is left connected and in the GCST_CONNECTED state from the
perspective of both A and B.
Figure 19. H.450.2 Blind Call Transfer Failure - Party C is Busy When Transfer Attempted
A
(Transferring)
IP CCLib
B
(Transferred)
App
B
(Transferred)
IP CCLib
C
(Transferred To)
App
gc_InvokeXfer(CRNp)
FACILITY(ctInitiate.Invoke)
SETUP(ctSetup.Invoke)
GCEV_REQ_XFER
(CRNp)
gc_AcceptXfer
(CRNp)
GCEV_
ACCEPT_XFER
(CRNp)
gc_MakeCall(CRNt,
CRNp)
Pre condition:
Primary call between A and B is in connected (not shown).
Party C has call connected to another party (not shown).
GCEV_DIALING
(CRNt)
A
(Transferring)
App
C
(Transferred To)
IP CCLib
RELEASECOMPLETE(Q.931Cause17UserBusy)
Party C is busy (not shown).
FACILITY(ctInitiate.ReturnResult = notAvailable)
GCEV_
INVOKE_XFER_
FAIL(CRNp,
GCRV_REMOTE
REJ_UNAVAIL)
GCEV_
DISCONNECTED
(GCRV_BUSY,
CRNt)
GCEV_
DROPCALL(CRNt)
gc_ReleaseCallEx
(CRNt)
GCEV_
RELEASECALL
(CRNt)
gc_DropCall
(CRNt)
Post condition:
Parties A and B remain connected.
Party C also remains connected (to another party not shown).
GCEV_XFER_FAIL
(CRNt,
GCRV_REMOTE
REJ_UNAVAIL)