Cisco 7960 Administrator's Manual page 134

Call Flow Scenarios for Successful Calls
Figure B-6 Cisco SIP IP Phone-to-Cisco SIP IP Phone Call Waiting
SIP IP
Phone User A
IP
1. INVITE B
2. 180 Ringing
3. 200 OK
4. ACK
2-way RTP channel
7. INVITE (c=IN IP4 0.0.0.0)
8. 200 OK
9. ACK
A is put on hold. The RTP channel between A and B is torn down.
15. INVITE (c=IN IP4 IP-User B)
16. 200 OK
17. ACK
A is taken off hold. The RTP channel between A and B is reestablished.
18. BYE
19. 200 OK
B has disconnected from A, but the call with C (on hold) remains.
Cisco SIP IP Phone 7960 Administrator Guide
B-26
IP Network
Appendix B
SIP IP
Phone User B
IP
5. INVITE C
6. 180 Ringing
10. 200 OK
11. ACK
2-way RTP channel
12. INVITE (c=IN IP4 0.0.0.0)
13. 200 OK
14. ACK
C is on hold. The RTP channel
between B and C is torn down.
20. INVITE (c=IN IP4 IP-User B)
21. 200 OK
22. ACK
C is taken off hold. The RTP
channel between B and C is
reestablished.
SIP Call Flows
SIP IP
Phone
User C
IP
78-10497-02