Yealink SIP-T2 SERIES Administrator's Manual page 1002

Administrator's Guide for SIP-T2 Series/T19(P) E2/T4 Series/CP860 IP Phones
Step
F11 BYE—User B to Proxy Server
F12 BYE—Proxy Server to User A
200 OK—User A to Proxy
F13
Server
200 OK—Proxy Server to User
F14
B
The following figure illustrates the scenario of an unsuccessful call caused by the called
user's being busy. 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:
1. User A calls User B.
2. User B is busy on the IP phone and unable or unwilling to take another call.
980
Action
response. The call session is now active.
User B terminates the call session by
sending a SIP BYE request to the proxy
server. The BYE request indicates that
User B wants to release the call.
The proxy server forwards the SIP BYE
request to User A to notify that User B
wants to release the call.
User A sends a SIP 200 OK response to
the proxy server. The 200 OK response
indicates that User A has received the
BYE request. The call session is now
terminated.
The proxy server forwards the SIP 200
OK response to User B to indicate that
User A has received the BYE request.
The call session is now terminated.
Description