Yealink SIP-T58V/A

Administrator’s Guide for SIP-T5 Series Smart Media Phones
798
Step
Action
Description
response notifies User B that the proxy
server has received the REFER message.
F11
REFER—Proxy Server to User A
The proxy server forwards the REFER
message to User A.
F12
202 Accepted—User A to Proxy
Server
User A sends a SIP 202 Accept response to
the proxy server. The 202 Accepted
response indicates that User A accepts the
transfer.
F13
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.
F14
BYE—Proxy Server to User A
The proxy server forwards the BYE request
to User A.
F15
200OK—User A to Proxy Server
User A sends a SIP 200 OK response to the
proxy server. The 200 OK response confirms
that User A has received the BYE request.
F16
200OK—Proxy Server to User B
The proxy server forwards the SIP 200 OK
response to User B.
F17
INVITE—User A to Proxy Server
User A sends a SIP INVITE request to the
proxy server. In the INVITE request, a
unique Call-ID is generated and the
Contact-URI field indicates that User A
requests the call.
F18
INVITE—Proxy Server to User C
The proxy server maps the SIP URI in the To
field to User C.
F19
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.
F20
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
F21
200OK—User C to Proxy Server
User C sends a SIP 200 OK response to the
proxy server. The 200 OK response notifies
the proxy server that the connection has
been made.