6a.4.6 Controllee UE initiated modify media on itself

23.2373GPPIP Multimedia Subsystem (IMS) Service ContinuityRelease 17Stage 2TS

6a.4.6.0 General

As per standard IMS UE behaviour, a Controllee UE may initiate a modification of a media flow that it terminates.

6a.4.6.1 Controller UE and Controllee UE belong to the same IMS subscription

The following information flow shows a Controllee UE initiating the modification of a media flow that it terminates. As a pre-requisite, there exists a Collaborative Session of which UE-1 is the Controller UE and UE-2 is a Controllee UE terminating a media flow, Media Flow A. There may be other media flows (on UE-1, UE-2 or other UEs) within the Collaborative Session; such media flows and UEs are not shown on this information flow; they shall not be impacted by this operation.

Figure 6a.4.6.1-1: Controllee UE initiated modify media flow on itself (same IMS subscription)

1. Controllee UE-2 sends a request to modify the characteristics of Media Flow-A (that it terminates), using standard IMS procedure.

2. The SCC AS updates the Remote Leg for allowed media changes, providing the new media flow characteristics from UE-2.

3. The SCC AS sends a successful response to the request sent by UE-2 at step 1.

6a.4.6.2 Controller UE and Controllee UE belong different IMS subscriptions under the same operator

The information flow shows a Controllee UE modifying a Media Flow that is originated from or terminated at the same Controllee UE. As a pre-requisite, there exists a Collaborative Session with two media flows, Media Flow–A on the Controller UE (UE-1) and Media Flow–B on the Controllee UE (UE-2).

Figure 6a.4.6.2-1: Controllee UE initiated media modify on itself (different IMS subscriptions under the same operator)

1. UE-2 sends a Modify media request to modify Media Flow-B on itself. The request includes media modification information pertaining to Media Flow-B. The IUT media modification request shall include enough information for the SCC AS to:

– identify that the modified media is Media Flow-B;

– identify that the modified media is on UE-2; and

– identify the modification requested to Media Flow-B.

2. The SCC AS-2 forwards the Media Modification Request to SCC AS-1 that serves the controller via S-CSCF-2 and S-CSCF-1.

3. The SCC AS-1 authorizes the Media Modification Request as specified in clause 6a.12.

3a~3b. If SCC AS-1 cannot authorize Media Modification Request, it queries controller UE-1 for authorization.

NOTE: Steps 3 (including 3a~3b) is optional depending on operator’s configuration.

4. SCC AS-1 identifies Media Flow-B as associated with UE-2 and sends Modify Media Request to UE-2 via S-CSCF-1 and S-CSCF-2. UE-2 modifies the Media Flow. The SCC AS-1 updates the Remote Leg with Media Flow–B modified.

5. The SCC AS-1 sends result of modify media request to UE-2.