Cisco Systems IP phone 7960 manual 50212

Appendix B SIP Call Flows

Call Flow Scenarios for Successful Calls

Figure B-12 Cisco SIP IP Phone-to Cisco SIP IP Phone 3-Way Calling

IP Network

IP

IP

IP

SIP IP	Proxy	Redirect	SIP IP	SIP IP
Phone	Server	Server	Phone	Phone
User A			User B	User C

1.INVITE B (Call-ID=1)

2.180 Ringing

3.200 OK

4.ACK

2-way RTP channel 1 between Users A and B established

5.INVITE (Call-ID=1, c=IN IP40.0.0.0)

6.200 OK

7.ACK

User A is on hold. The RTP channel 1 between User A and B is torn down.

12.INVITE A (Call-ID=1, c=IN IP4 IP-User B)

13.200 OK

User A is taken off hold. The RTP channel 1 between User A and B is re-established.

8.INVITE C (Call-ID=2)

9.180 Ringing

10.200 OK

11. ACK

2-way RTP channel 2 between User B and C is established

User B mixes the RTP channels 1 and 2 and establishes a conference brigde between Users A and C

50212

	Cisco SIP IP Phone 7960 Administrator Guide
78-10497-02		B-53