Yealink SIP T46G Administrator's Manual page 410

Step Action
F27 BYE—User A to Proxy Server
F28 BYE—Proxy Server to User B
200OK—User B to Proxy
F29
Server
200OK—Proxy Server to User
F30
A
Description
response indicates that User B accepts
the transfer.
User A terminates the call session by
sending a SIP BYE request to the proxy
server. The BYE request indicates that
User A wants to release the call.
The proxy server forwards the BYE
request to User B.
User B sends a SIP 200 OK response to
the proxy server. The 200 OK response
notifies User A that User B has received
the BYE request.
The proxy server forwards the SIP 200
OK response to User A.
Appendix
397