Yealink T46G Administrator's Manual page 403

User B accepts the call from User C.
4.
User A
F1. INVITE B
F4. 180 Ringing
F6. 200 OK
F7. ACK
2-way RTP channel established
F10. INVITE A
F11. 180 Ringing
F13. INVITE B ( sendonly )
F316 200 OK
F17. ACK
No RTP Packets being sent
F19. 200 OK
F22. ACK
Step
F1 INVITE—User A to Proxy Server
Proxy Server
F2. INVITE B
F3. 180 Ringing
F5. 200 OK
F8. ACK
F14. INVITE B ( sendonly )
F15. 200 OK
F18. ACK
2-way RTP channel established
Action
User B
F9. INVITE A
F12. 180 Ringing
F20. 200 OK
F21. ACK
Description
User A sends an INVITE message to a proxy
server. The INVITE request is an invitation to
User B to participate in a call session.
In the INVITE request:
Appendix
User C
389