Cisco Systems 186, 188

D-13

Cisco ATA 186 and Cisco ATA 188 Analog Telephone Adaptor Administrator’s Guide (SIP)

OL-3410-01

AppendixD SIP Call Flows

Call Flow Scenarios for Successful Calls

TableD-7 Action Descriptions

Step Action Description

Step1 INVITE—Cisco ATA A to SIP server Cisco ATA A sends a call session INVITE request to the SIP

server to pass on to Cisco ATA B.

Step2 100 Trying—SIP server to Cisco ATA A SIP server returns a 100 Trying message, indicating that the

INVITE request has been received.

Step3 407 Proxy Authentication Required— SIP server

to Cisco ATA A

SIP server returns a request for authentication to CiscoATA A.

Step4 ACK—CiscoATA A to SIP server Cisco ATA A acknowledges the request for authentication.

Step5 INVITE—Cisco ATA A to SIP server Cisco ATA A sends a call session INVITE request along with

authentication credential to the SIP server to pass on to

Cisco ATA B.

Step6 100 Trying—SIP server to Cisco ATA A SIP server returns a 100 Trying message, indicating that the

INVITE request has been received.

Step7 INVITE—SIP server to Cisco ATA B SIP server sends the call session INVITE request to Cisco ATA

Step8 100 Trying—Cisco ATA B to SIP server CiscoATA B returns a 100 trying message indicating that the

INVITE request has been received.

Step9 180 Ringing—Cisco ATA B to SIP server Cisco ATA B sends a 180 ringing response to the SIP server to

pass on to Cisco ATA A.

Step10 180 Ringing—SIP server to Cisco ATA A SIP server sends the 180 ring ing response to Cisco ATA A.

Step11 200 OK—Cisco ATA B to SIP server Cisco ATA B sends a 200 OK message to the SIP server

indicating that a connection has been established.

Step12 200 OK—SIP server to Cisco ATA A SIP server passes the 200 OK message to Cisco ATA A.

Step13 ACK—Cisco ATA A to SIP server CiscoATA A sends acknowledgment of the 200 OK response to

the SIP server to pass on to CiscoATA B.

Step14 ACK—SIP server to Cisco ATA B SIP server passes ACK response to CiscoATA B.

A two-way voice path is established between CiscoATA A and Cisco ATA B.

Step15 BYE—Cisco ATA A to SIP server CiscoATA A terminates the call session and sends a BYE

request to the SIP server indicating that CiscoATA A wants to

terminate the call.

Step16 100 Trying—SIP server to Cisco ATA A SIP server returns a 100 trying message indicating that the BYE

request has been received.

Step17 BYE—SIP server to Cisco ATA B SIP server passes the BYE request to Cisco ATA B.

Step18 200 OK—Cisco ATA B to SIP server Cisco ATA186 B sends a 200 OK message to the SIP server

indicating that Cisco ATA186 B has received the BYE request.

Step19 200 OK—SIP server to Cisco ATA A SIP server passes th e BYE request to Cisco ATA A.