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354 Dialogic
®
Global Call IP Technology Guide — November 2007
Dialogic Corporation
Third Party Call Control (3PCC) Operations and Multimedia Support
• Cancelling a re-INVITE Request
• Receiving an Invalid Answer SDP
• OPTIONS Request on an Active Dialog
5.4.1 First Party Call Establishment in Third Party Call Control
Mode
Figure 67 shows how to implement a simple point-to-point SIP call between two endpoints (party
A and party B). The Dialogic
®
Global Call API library is initialized in 3PCC mode. A third party
call controller is not used:
Figure 67. First Party Call Control Establishment in Third Party Call Control Mode
IPML
Library A
Application A
Global Call
Library A
(IPCCLIB)
Application B
Global Call
Library B
(IPCCLIB)
IPML
Library B
gc_MakeCall
SDP Offer 1
GCEV_DIALING
ipm_StartMedia
(RCV_ONLY)
INVITE
SDP Offer 1
GCEV_OFFERED
SDP Offer 1
IPMEV_START_
MEDIA
ipm_StartMedia
(TxRx)
RTP
IPMEV_START
_MEDIA
gc_SetUserInfo
SDP Answer 1
gc_AcceptCall
GCEV_ACCEPT
180 Ringing
SDP Answer 1
GCEV_ALERTING
SDP Answer 1
ipm_ModifyMedia
(TxRx)
RTP
IPMEV_MODIFY
_MEDIA
gc_AnswerCall
200 OK
SDP Answer 1
GCEV_CONNECTED
GCEV_SIP_200OK
gc_SipAck
ACK
GCEV_ANSWERED
GCEV_SIP_ACK
GCEV_SIP_ACK_OK
gc_DropCall
BYE
200 OK
No SDP
GCEV_
DISCONNECTED
gc_DropCall
GCEV_DROPCALL
GCEV_DROPCALL
ipm_Stop
IPMEV_STOP
gc_ReleaseCallEx ipm_Stop
GCEV_RELEASECALL
IPMEV_STOP
gc_ReleaseCallEx
GCEV_RELEASECALL
SDP offer has only one
receive coder specified,
allowing IPML to "start early"
on the offering side.
SDP added by the application
in a provisional response will
be automatically included in
the dialog's final response.
The SDP will only be delivered
to the application one time.
No GCEV_SIP_200OK
events are sent to the
application during dialog
dis-establishment.