Call Transfer Without Consultation - Yealink W60P Administrator's Manual

Administrator's Guide for W60P DECT IP Phones
Step
F16 200 OK—Proxy Server to User A
F17 ACK—User A to Proxy Server
F18 ACK—Proxy Server to User B
F19 200 OK—User A to Proxy Server
F20 200 OK—Proxy Server User C
F21 ACK—User C to Proxy Server
F22 ACK—Proxy Server to User A

Call Transfer without Consultation

The following figure illustrates a successful call between Yealink SIP DECT IP phones in which
two parties are in a call and then one of the parties transfers the call to a third party without
consultation. This is called a blind transfer. In this call flow scenario, the end users are User A,
User B, and User C. They are all using Yealink SIP DECT IP phones, which are connected via an IP
network.
502
Action
INVITE was successfully processed.
The proxy server forwards the 200 OK
response to User A. The 200 OK response
notifies User B is successfully placed on
hold.
User A sends an ACK message to the
proxy server. The ACK confirms that User
A has received the 200 OK response. The
call session is now temporarily inactive.
No RTP packets are being sent.
The proxy server sends the ACK message
to User B. The ACK confirms that the
proxy server has received the 200 OK
response.
User A sends a 200 OK response to the
proxy server. The 200 OK response
notifies that the connection has been
made.
The proxy server forwards the 200 OK
message to User C.
User C sends a SIP ACK to the proxy
server. The ACK confirms that User C has
received the 200 OK response. The call
session is now active.
The proxy server forwards the SIP ACK to
User A to confirm that User C has received
the 200 OK response.
Description