B-51
Cisco SIP IP Phone 7960 Administrator Guide
78-10497-02
AppendixB SIP Call Flows Call Flow Scenarios for Successful Calls
6180 Ringing—SIP proxy server
to Cisco SIP IP phone A SIP proxy server sends a SIP 180 Ringing response to
Cisco SIP IP phone A.
The timeout expires before the phone is answered.
7CANCEL (Ring Timeout)—SIP
proxy server to Cisco SIP IP
phone B
SIP proxy server sends a CANCEL request to Cisco SIP IP
phone B to cancel the invitation.
8200 OK—Cisco SIP IP phone B
to SIP proxy server Cisco SIP IP phone B sends a SIP 200 OK response to the
SIP proxy server. The response confirms receipt of the
cancellation request.
9INVITE—SIP proxy server to
Cisco SIP IP phone C SIP proxy server sends a SIP INVITE request to Cisco SIP
IP phone C. The INVITE request is an invitation to User C
to participate in a call session.
10 180 Ringing—Cisco SIP IP
phone C to SIP proxy server Cisco SIP IP phone C sends a SIP 180 Ringing response to
the SIP proxy server
11 200 OK—Cisco SIP IP phone C
to SIP proxy server Cisco SIP IP phone C sends a SIP 200 OK response to the
SIP proxy server.
12 200 OK—SIP proxy server to
Cisco SIP IP phone A SIP proxy server forwards the SIP 200 OK response to
Cisco SIP IP phone A.
13 ACK—Cisco SIP IP phone A to
SIP proxy server Cisco SIP IP phone A sends a SIP ACK to the SIP proxy
server. The ACK confirms that Cisco SIP IP phone A has
received the 200 OK response from Cisco SIP IP phone C.
14 ACK—SIP proxy server to Cisco
SIP IP phone C SIP proxy server forwards the SIP ACK to the Cisco SIP IP
phone C. The ACK confirms that Cisco SIP IP phone A has
received the 200 OK response from Cisco SIP IP phone C.
Step Action Description