Table of Contents
Advertisement
Appendix B
SIP Call Flows
Figure B-20 A Successful Call from a Cisco SIP IP Phone to a Gateway (Backup Proxy)
SIP IP Phone
User A
Step
Action
INVITE—Cisco SIP IP phone to
1.
primary proxy
INVITE—Cisco SIP IP phone to
2.
primary proxy (second try)
INVITE—Cisco SIP IP phone to
3.
primary proxy (third try)
INVITE—Cisco SIP IP phone to
4.
primary proxy (fourth try)
Primary
IP
1. INVITE
2. INVITE (retry)
3. INVITE (retry)
4. INVITE (retry)
5. INVITE (retry)
6. INVITE (retry)
7. INVITE (retry)
8. INVITE (retry)
11. 100 Trying
13. 180 Ringing
15. 200 OK
16. ACK
18. BYE
21. 200 OK
Description
Cisco SIP IP phone tries to connect to the proxy by sending out the INVITE
message.
Cisco SIP IP phone retries a second time to connect to the proxy by sending out
the INVITE message.
Cisco SIP IP phone retries a third time to connect to the proxy by sending out the
INVITE message.
Cisco SIP IP phone retries a fourth time to connect to the proxy by sending out
the INVITE message.
GW
9. Setup
10. Call Proceeding
12. Alerting
14. Connect
17. Connect ACK
2-way voice path
19. Disconnect
20. Release
22. Release Complete
Cisco SIP IP Phone Administrator Guide
Call Flow Scenarios for Failed Calls
User B
PBX
B-55
- Quick Links:
- Using the Command-Line Interface
Hide quick links:
Advertisement
Table of Contents
