Successful Call Setup And Call Hold - Yealink CP969 Administrator's Manual

Step
180 Ringing—Proxy Server to
User A
F4
CANCEL—User A to Proxy Server
F5
CANCEL—Proxy Server to User B
F6
200 OK—User B to Proxy Server
F7
200 OK—Proxy Server to User A
F8

Successful Call Setup and Call Hold

The following figure illustrates a successful call setup and call hold. In this scenario, the two end
users are User A and User B. User A and User B are located at Yealink SIP IP phones.
The call flow scenario is as follows:
User A calls User B.
1.
User B answers the call.
2.
Action
The proxy server forwards the 180 Ringing
response to User A. User A hears the
ring-back tone indicating that User B is
being alerted.
User A sends a SIP CANCEL request to the
proxy server after not receiving an
appropriate response within the time
allocated in the INVITE request. The SIP
CANCEL request indicates that User A wants
to disconnect the call.
The proxy server forwards the SIP CANCEL
request to notify User B that User A wants
to disconnect the call.
User B sends a SIP 200 OK response to the
proxy server. The SIP 200 OK response
indicates that User B has received the
CANCEL request.
The proxy server forwards the SIP 200 OK
response to notify User A that the CANCEL
request has been processed successfully.
Appendix
Description
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