Cisco 7960G Administration Manual page 134

Call Flow Scenarios for Successful Calls
Figure B-12 Network Call Forwarding (Busy)
SIP IP
Phone
User A
1. INVITE B
11. 200 OK
12. ACK
2-way RTP channel
Cisco Unified IP Phone 7960G and 7940G Administration Guide for Release 8.0 (SIP)
B-34
IP
Proxy
Server
2. INVITE B
3. 300 Multiple Choices
4. ACK
5. INVITE B
6. 486 Busy Here
7. ACK
8. INVITE C
9. 180 Ringing
10. 200 OK
13. ACK
IP Network
Redirect
Server
Appendix B SIP Call Flows
IP IP
SIP IP SIP IP
Phone Phone
User B User C
OL-7890-01