Cisco 7960G Administration Manual page 115

Appendix B SIP Call Flows
Figure B-6
SIP IP
Phone User A
1. INVITE B
2. 180 Ringing
3. 200 OK
4. ACK
2-way RTP channel
7. INVITE (a=sendonly)
8. 200 OK
9. ACK
A is put on hold. The RTP channel between A and B is torn down.
15. INVITE (a=sendrecv)
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.
OL-7890-01
Call Waiting
IP
Cisco Unified IP Phone 7960G and 7940G Administration Guide for Release 8.0 (SIP)
SIP IP
Phone User B
IP Network
Call Flow Scenarios for Successful Calls
SIP IP
Phone
User C
IP IP
5. INVITE C
6. 180 Ringing
10. 200 OK
11. ACK
2-way RTP channel
12. INVITE (a=sendonly)
13. 200 OK
14. ACK
C is on hold. The RTP channel
between B and C is torn down.
20. INVITE (a=sendrecv)
21. 200 OK
22. ACK
C is taken off hold. The RTP
channel between B and C is
reestablished.
B-15