Cisco 7960 Administrator's Manual page 116

Call Flow Scenarios for Successful Calls
Figure B-2 Gateway-to-Cisco SIP IP Phone Call—Successful Call Setup and Call Hold
PBX A
User A
1. Setup
3. Call Proceeding
6. Alerting
8. Connect
10. Connect ACK
2-way voice path
2-way voice path
Cisco SIP IP Phone 7960 Administrator Guide
B-8
GW1 IP Network
2. INVITE
4. 100 Trying
5. 180 Ringing
7. 200 OK
9. ACK
2-way RTP channel
11. INVITE (c=IN IP4 0.0.0.0)
12. 200 OK
13. ACK
No RTP packets being sent
14. INVITE (c=IN IP4 IP-User B)
15. 200 OK
16. ACK
2-way VP
Appendix B SIP Call Flows
SIP IP Phone
User B
IP
78-10497-02