200 OK— User B to Proxy
Server
User B sends a SIP 200 OK response to
the proxy server. The 200 OK response
notifies User A that the connection has
been made.
200OK—Proxy Server to User
A
The proxy server forwards the 200 OK
message to User A. The 200 OK
response notifies User A that the
connection has been made.
ACK—User A to Proxy Server
User A sends a SIP ACK to the proxy
server. The ACK confirms that User A
has received the 200 OK response. The
call session is now active.
ACK—Proxy Server to User B
The proxy server sends the SIP ACK to
User B. The ACK confirms that the proxy
server has received the 200 OK
response. The call session is now active.
BYE—User B to Proxy Server
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.
BYE—Proxy Server to User A
The proxy server forwards the SIP BYE
request to User A to notify that User B
wants to release the call.
200 OK—User A to Proxy
Server
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.
200 OK—Proxy Server to User
B
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.