Filter
Top Products
366 Dialogic
®
Global Call IP Technology Guide — November 2007
Dialogic Corporation
Third Party Call Control (3PCC) Operations and Multimedia Support
5.4.5 Cancelling a re-INVITE Request
Figure 76 shows the host application behavior when a re-INVITE request has been cancelled. The
re-INVITE request is initially made to modify the coder used by the active dialog:
Figure 76. Cancelling a Coder Switch using re-INVITE
IPML
Library A
Application A
Global Call
Library A
(IPCCLIB)
Application B
Global Call
Library B
(IPCCLIB)
IPML
Library B
GCEV_DIALING
ipm_StartMedia
(RCV_ONLY)
INVITE
SDP Offer 1
GCEV_OFFERED
SDP Offer 1
RTP
200 OK
SDP Answer 1
GCEV_CONNECTED
SDP Answer 1
ipm_ModifyMedia
(TxRx)
RTP
IPMEV_MODIFY
_MEDIA
gc_SipAck
ACK
GCEV_ANSWERED
GCEV_SIP_ACK
GCEV_REQ_
MODIFY_CALL
SDP Offer 2
re-INVITE
SDP Offer 2
gc_ReqModifyCall
IP_MSGTYPE_
SIP_CANCEL
CANCEL
GCEV_MODIFY
_CALL_CANCEL
Per RFC3264, a stream
that is rejected in the answer
must not send media
for that stream.
It is assumed that the original
stream remained intact becuase
the modification was rejected. In
400-600 responses to CANCEL
requests that require SDP,
Global Call will generate the SDP.
GCEV_SIP_200OK
GCEV_SIP_ACK_OK
gc_ReqModifyCall
SDP Offer 2
200 OK
CSeq number CANCEL
487 - Request Terminated
CSeq number re-INVITE
ACK
GCEV_CANCEL
_MODIFY_CALL
SIP ACK is automatically
generated by Global Call
for INVITE and re-INVITE failures.
If these ACKs require "SDP reject
answers", Global Call will
provide them.
IPMEV_START_MEDIA
gc_MakeCall
SDP Offer 1
gc_SetUserInfo
SDP Answer 1
ipm_StartMedia(TxRx)
gc_AnswerCall