Always Call Forward - Yealink SIP-T2XP Administrator's Manual

Always Call Forward

The following figure illustrates successful call forwarding between Yealink SIP IP phones
in which User B has enabled always call forward. The incoming call is immediately
forwarded to User C when User A calls User B. In this call flow scenario, the end users are
User A, User B, and User C. They are all using Yealink SIP IP phones, which are connected
via an IP network.
The call flow scenario is as follows:
1. User B enables always call forward, and the destination number is User C.
2. User A calls User B.
3. User B forwards the incoming call to User C.
4. User C answers the call.
Call is established between User A and User C.
User A
F1. INVITE B
F5. 302 Move Temporarily
F6. ACK
F7. INVITE C
F10. 180 Ringing
F12. 200 OK
F13. ACK
Proxy Server
F2. INVITE B
F3. 302 Move Temporarily
F4. ACK
F8. INVITE C
F9. 180 Ringing
F11. 200 OK
F14. ACK
2-way RTP channel established
User B
Appendix
User C
427