User`s guide

Dialogic
®
System Release 6.0 PCI for Windows
®
Release Update, Rev 62 — January 30, 2008 198
Dialogic Corporation
INVOKE_XFER_REJ or INVOKE_XFER_FAIL event with cause. No NOTIFY will be sent
from party B to party A if REFER is not accepted by 202 Accepted from party B. The
primary call and secondary call, if any, remain in connected state after any transfer failure.
The most common transfer failure scenarios are described in the following topics:
• Party B Rejects Call Transfer
• No Response from Party B
• No Initial NOTIFY after REFER Accepted
• REFER Subscription Expires
• No Response from Party C
• Party B Drops Transferred Call Early
• Party C Is Busy When Transfer Attempted
Party B Rejects Call Transfer
Figure 9 illustrates a scenario in which the application at the transferred endpoint
(Transferee or party B) calls gc_RejectXfer( ) to signal the Transferor (party A) that it
cannot participate in a transfer. The application may specify any valid SIP rejection
reason, such as the 480 Temporarily Unavailable shown in the figure; if no reason is
specified, the default reason sent is 603 Decline. As a result of the rejection, the
GCEV_INVOKE_XFER_REJ termination event is received at the Transferor application
(party A). The original primary call is left connected and in the GCST_CONNECTED state
from the perspective of both party A and party B.
Figure 9. SIP Call Transfer Failure - Party B Rejects Call Transfer
No Response from Party B
Figure 10 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
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