IMS Conference Call Flow Diagrams

These diagrams cover IMS conference setup with REFER-based invitations. To inspect a conference call in a live trace, VisualEther turns the Wireshark SIP capture into a sequence diagram you can read at a glance.

This sequence diagram shows an IMS user creating a conference by using a conference-factory URI. The conference is created at a MRFC-AS of the users home network. The steps involved in the conference scenario covered here are:

• The conference initiator UE uses the conference factory URI to initiate a conference with the MRFC-AS (Multimedia Resource Function Control/Application Server).
• The MRFC-AS assigns a conference URI to the conference and configures the MRFP (Multimedia Resource Function Processor).
• The conference call is setup and the RTP data begins flowing between the conference initiating UE and the MRFP.
• The conference initiator then uses the refer procedure to add more users to the conference. The new users establish a call to the conference URI passed in the refer message.
• When the conference is in progress, RTP media streams are being mixed and propagated to all the participants.
• The conference user drops out of the conference. All users are notified for this exit from the conference.

The message sequence is analyzed from call flows that focus on different aspects of the message interactions:

• IMS Conference Call Flow
• IMS Conference Call Poster (11x17)
• IMS Conference Flow Overview
• Conference Call (IMS network is treated as a black box)
• Conference Call (IMS network components are treated as black boxes)
• Conference Initiating UE Role (Sequence Diagram)
• Conference Initiating UE Role (Collaboration Diagram)
• Conference Initiator S-CSCF Role (Sequence Diagram)
• Conference Initiator S-CSCF Role (Collaboration Diagram)
• Multimedia Resource Function Controller Role (Sequence Diagram)
• Multimedia Resource Function Controller Role (Collaboration Diagram)
• Multimedia Resource Function Processor Role (Sequence Diagram)