sends the INVITE request to User C.
180 Ringing—User C to Proxy
Server
User C sends a SIP 180 Ringing
response to the proxy server. The 180
Ringing response indicates that the user
is being alerted.
180 Ringing—Proxy Server to
User A
The proxy server forwards the 180
Ringing response to User A. User A
hears the ring-back tone indicating that
User C is being alerted.
200OK—User C to Proxy
Server
User C 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 SIP 200
OK response 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 C
The proxy server forwards the ACK
message to User C. The ACK confirms
that the proxy server has received the
200 OK response. The call session is
now active.
REFER—User A to Proxy
Server
User A sends a REFER message to the
proxy server. User A performs a transfer
of User B to User C.
202 Accepted—Proxy Server
to User A
The proxy server sends a SIP 202
Accepted response to User A. The 202
Accepted response notifies User A that
the proxy server has received the REFER
message.
REFER—Proxy Server to User B
The proxy server forwards the REFER
message to User B.
202 Accepted—User B to
Proxy Server
User B sends a SIP 202 Accept response
to the proxy server. The 202 Accepted
To Next Page
Loading...
Need help?
General
