Appendix B SIP Call Flows
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| Call Flow Scenarios for Successful Calls |
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Step | Action | Description | |
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9 | Cisco SIP IP phone B sends a SIP ACK to Cisco SIP IP | ||
| Cisco SIP IP phone A | phone A. The ACK confirms that Cisco SIP IP phone B has | |
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| received the 200 OK response from Cisco SIP IP phone A. | |
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The RTP channel between Cisco SIP IP phone A and Cisco SIP IP phone B is torn down. | |||
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10 | 200 | Cisco SIP IP phone B sends a SIP 200 OK response to | |
| to Cisco SIP IP phone C | Cisco SIP IP phone C. The 200 OK response notifies Cisco | |
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| SIP IP phone C that the connection has been made. | |
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11 | Cisco SIP IP phone C sends a SIP ACK to Cisco SIP IP | ||
| Cisco SIP IP phone B | phone B. The ACK confirms that Cisco SIP IP phone C has | |
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| received the 200 OK response from Cisco SIP IP phone B. | |
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| The ACK might contain a message body with the final | |
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| session description to be used by Cisco SIP IP phone B. If | |
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| the message body of the ACK is empty, Cisco SIP IP phone | |
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| B uses the session description in the INVITE request. | |
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A
12 | Cisco SIP IP phone B sends a | |
| to Cisco SIP IP phone C | SIP IP phone C with new SDP session parameters (IP |
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| address), which are used to place the call on hold. |
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| Call_ID=2 |
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| SDP: c=IN IP4 0.0.0.0 |
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| To establish the call between phone B and phone C, the IP |
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| address of phone B is inserted into the c= SDP field. |
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13 | 200 | Cisco SIP IP phone C sends a SIP 200 OK response to |
| to Cisco SIP IP phone B | Cisco SIP IP phone B. |
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14 | Cisco SIP IP phone B sends a SIP ACK to Cisco SIP IP | |
| Cisco SIP IP phone C | phone C. The ACK confirms that Cisco SIP IP phone B has |
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| received the 200 OK response from Cisco SIP IP phone C. |
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The RTP channel between Cisco SIP IP phone B and Cisco SIP IP phone C is torn down.
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| Cisco SIP IP Phone 7960 Administrator Guide |
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