Appendix B SIP Call Flows
Call Flow Scenarios for Successful Calls
Step | Action |
| Description | |||
|
|
|
| |||
6 |
| Gateway 1 sends an Alert message to User A. The Alert | ||||
|
|
|
|
| message indicates that Gateway 1 has received a 180 | |
|
|
|
|
| Ringing response from the Cisco SIP IP phone. User A | |
|
|
|
|
| hears the ringback tone that indicates that User B is being | |
|
|
|
|
| alerted. | |
|
|
|
| |||
7 | 200 |
| The Cisco SIP IP phone sends a SIP 200 OK response to | |||
| Gateway 1 |
| Gateway 1. The 200 OK response notifies Gateway 1 that | |||
|
|
|
|
| the connection has been made. | |
|
|
|
| |||
8 |
| Gateway 1 sends a Connect message to PBX A. The | ||||
|
|
|
|
| Connect message notifies PBX A that the connection has | |
|
|
|
|
| been made. | |
|
|
|
| |||
9 |
| Gateway 1 sends a SIP ACK to the Cisco SIP IP phone. The | ||||
| IP phone |
| ACK confirms that User A has received the 200 OK | |||
|
|
|
|
| response. The call session is now active. | |
|
|
|
| |||
10 | Connect |
| PBX A acknowledges Gateway 1’s Connect message. | |||
| Gateway 1 |
|
|
| ||
|
|
|
| |||
11 |
| User B puts User A on hold. The Cisco SIP IP phone sends | ||||
| Gateway 1 |
| a SIP INVITE request to Gateway 1. | |||
|
|
|
| |||
12 | 200 |
| Gateway 1 sends a SIP 200 OK response to the Cisco SIP | |||
| SIP IP phone |
| IP phone. The 200 OK response notifies the Cisco SIP IP | |||
|
|
|
|
| phone that the INVITE was successfully processed. | |
|
|
|
| |||
13 |
| The Cisco SIP IP phone sends a SIP ACK to Gateway 1. | ||||
| Gateway 1 |
| The ACK confirms that the Cisco SIP IP phone has | |||
|
|
|
|
| received the 200 OK response. The call session is now | |
|
|
|
|
| temporarily inactive. No RTP packets are being sent. | |
|
|
|
| |||
14 |
| User B takes User A off hold. The Cisco SIP IP phone | ||||
| Gateway 1 |
| sends a SIP INVITE request to Gateway 1. | |||
|
|
|
| |||
15 | 200 |
| Gateway 1 sends a SIP 200 OK response to the Cisco SIP | |||
| SIP IP phone |
| IP phone. The 200 OK response notifies the Cisco SIP IP | |||
|
|
|
|
| phone that the INVITE was successfully processed. | |
|
|
|
| |||
16 |
| The Cisco SIP IP phone sends a SIP ACK to Gateway 1. | ||||
| Gateway 1 |
| The ACK confirms that the Cisco SIP IP phone has | |||
|
|
|
|
| received the 200 OK response. The call session is now | |
|
|
|
|
| active. | |
|
|
|
|
|
| |
|
|
| Cisco SIP IP Phone 7960 Administrator Guide | |||
|
|
| ||||
|
|
|
|
| ||
|
|
|
| |||
