Called Number Does Not Answer - Cisco 7960G Administrator's Manual

Appendix B SIP Call Flows
Step Action
8. ACK—Gateway 1 to Cisco SIP IP phone Gateway 1 sends a SIP ACK to the phone. The ACK confirms that A has
9. Release Complete—Gateway 1 to
PBX A

Called Number Does Not Answer

Figure B-19
answer.
Figure B-19 Called Number Does Not Answer
User A
Description
received the 486 Busy Here response. The call session attempt terminates.
Gateway 1 sends a Release Complete message to PBX A, and the call
session attempt terminates.
illustrates the call flow in which User A initiates a call to User B, but User B does not
GW1
PBX A
1. Setup
2. INVITE
3. Call Proceeding
4. 100 Trying
5. 180 Ringing
6. Alerting
7. CANCEL
8. Disconnect
9. Release
10. 200 OK
11. Release Complete
IP Network
Cisco SIP IP Phone Administrator Guide, Release 6.x and 7.x
Call Flow Scenarios for Failed Calls
SIP IP Phone
User B
IP
B-49