C-57

SIP IP Phone to SIP IP Phone: Call Return
Figure C-21. SIP IP Phone to SIP IP Phone: Call Return — Diagram 1
SIP Phone UA Marshal
1. INVITE
2. 100
Redirect Server
3. INVITE
4. 302
5. ACK
Feature Server:
Call Return
6. INVITE
7. 100
8. INVITE
9. 302
10. ACK
11. INVITE
12. 100
13. INVITE
14. 302
15. ACK
SIP Phone