Cisco 7960 - Call Flow Scenarios for Failed Calls; Gateway-To-Cisco SIP IP Phone-Called User Is Busy

Appendix B SIP Call Flows
Call Flow Scenarios for Failed Calls
B-58
Cisco SIP IP Phone 7960 Administrator Guide
78-10497-02
Call Flow Scenarios for Failed Calls
This section describes call flows for the following scenarios, which illustrate
unsuccessful calls:
•
Gateway-to-Cisco SIP IP Phone—Called User is Busy, page B-58
•
Gateway-to-Cisco SIP IP Phone—Called User Does Not Answer, page B-60
•
Gateway-to-Cisco SIP IP Phone—Client, Server, or Global Error, page B-63
•
Cisco SIP IP Phone-to-Cisco SIP IP Phone—Called User is Busy, page B-66
•
Cisco SIP IP Phone-to-Cisco SIP IP Phone—Called User Does Not Answer,
page B-68
•
Cisco SIP IP Phone-to-Cisco SIP IP Phone—Authentication Error, page B-70
Gateway-to-Cisco SIP IP Phone—Called User is Busy
Figure B-13 illustrates an unsuccessful call in which User A initiates a call to
User B but User B is on the phone and is unable or unwilling to take another call.
Figure B-13 Gateway-to-Cisco SIP IP Phone—Called User is Busy
IP
3. Call Proceeding
6. Disconnect (Busy)
1. Setup
7. Release
PBX A
User A
GW1 IP Network
4. 100 Trying
5. 486 Busy Here
8. ACK
2. INVITE
9. Release Complete
41725
SIP IP Phone
User B