Call Flow Scenarios For Failed Calls; Gateway To Cisco Sip Ip Phone In A Sip Network; Called Number Is Busy - Cisco 7960G Administration Manual

Appendix B SIP Call Flows
Step Action
ACK—Cisco SIP IP phone
9.
(A) to emergency proxy
ACK—Emergency proxy to
10.
Cisco SIP IP phone (B)
BYE—Cisco SIP IP phone
11.
(A) to emergency proxy
BYE—Emergency proxy to
12.
Cisco SIP IP phone (B)
200 OK—Cisco SIP IP phone
13.
(B) to emergency proxy
14. 200 OK—Emergency proxy to
Cisco SIP IP phone (A)

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 in a SIP Network

The following scenarios are failed calls in the gateway to a Cisco SIP IP phone:
•
•
•

Called Number Is Busy

Figure B-18
the phone and is unable or unwilling to take another call.
OL-7890-01
Description
A acknowledges the emergency proxy's Connect message.
The emergency proxy acknowledges B's Connect message.
A terminates the call session and sends a SIP BYE request to the emergency
proxy. The request indicates that A wants to release the call.
The emergency proxy terminates the call session and sends a SIP BYE request to
User B. The request indicates that the emergency proxy wants to release the call.
User B sends a SIP 200 OK response to the emergency proxy. The response
notifies the emergency proxy that B has received the BYE request.
The emergency proxy sends a SIP 200 OK response to A. The response notifies A
that the emergency proxy has received the BYE request.
Gateway to Cisco SIP IP Phone in a SIP Network, page B-47
Cisco SIP IP Phone to Cisco SIP IP Phone in a SIP Network, page B-52
Called Number Is Busy, page B-47
Called Number Does Not Answer, page B-49
Client, Server, or Global Error, page B-50
illustrates an unsuccessful call in which Use A initiates a call to User B, but User B is on
Cisco Unified IP Phone 7960G and 7940G Administration Guide for Release 8.0 (SIP)
Call Flow Scenarios for Failed Calls
B-47