Cisco Sip Ip Phone-To-Cisco Sip Ip Phone Call Transfer Without Consultation - Cisco 7960 Administrator's Manual

Appendix B SIP Call Flows
Step Action
16
ACK—Cisco SIP IP phone B to
Cisco SIP IP phone C
A two-way RTP channel is reestablished between Cisco SIP IP phone B and Cisco SIP IP phone C.
Cisco SIP IP Phone-to-Cisco SIP IP Phone Call Transfer without
Consultation
Figure B-7 illustrates a successful call between Cisco SIP IP phones in which two
parties are in a call and then one of the participants transfers the call to a third
party without first contacting the third party. This is called a blind transfer. In this
call flow scenario, the end users are User A, User B, and User C. They are all
using Cisco SIP IP phones, which are connected via an IP network.
The call flow scenario is as follows:
1.
2.
3.
78-10497-02
Description
Cisco SIP IP phone B sends a SIP ACK to Cisco SIP IP
phone C. The ACK confirms that Cisco SIP IP phone B has
received the 200 OK response from Cisco SIP IP phone A.
User A calls User B.
User B answers the call.
User B transfers the call to User C.
Call Flow Scenarios for Successful Calls
Cisco SIP IP Phone 7960 Administrator Guide
B-31