6a.11 Session Replication by remote party

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

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

6a.11.1 Session replication initiated by target UE

The call flow in the figure below shows the scenario where UE-2 requests replication of a session ongoing between UE-1 and a remote UE. After the replication procedure is complete, the sessions are independent.

Figure 6a.11.1-1: Session replication initiated by target UE

1. UE-2 obtains information about the existing sessions and their media flows.

2. UE-2 uses the session information obtained and to send a session replication request towards the SCC AS. The request indicates that this request is for a session replication request.

3. The SCC AS performs authorization as specified in clause 6a.12; in particular, the SCC AS requests UE-1 to authorize the replication request or the SCC AS authorizes the request on behalf of UE-1 (e.g. pre-configured).

4. If the request is authorized, UE-2 creates a new session with the remote UE. When the new session is established, the state of the original media is replicated e.g. same playback state; same used media etc. is replicated. If the remote party does not support setting up a replicated session, the flow will fail.

NOTE: The session replication data and how it is conveyed from the source UE is not specified in this document.

5. A new session, where the media is a replica of Media-A, is established between UE-2 and the remote UE.

6a.11.2 Session replication initiated by source UE

The call flow in the figure below shows the scenario where UE-1 requests replication of a session ongoing between UE 1 and a remote UE to UE-2. After the replication procedure is complete, the sessions are independent. As a pre-requisite, there exists a Session with Media–A on UE-1.

Figure 6a.11.2-1: Session replication initiated by source UE

1. UE-1 requests to replicate current session to UE-2 by sending Session Replication Request to SCC AS. The Session Replication Request should contain enough information for the SCC AS to:

– identify that the session replication source is UE-1;

– identify that the session replication target is UE-2;

– identify the remote party.

2. SCC AS performs authorization as specified in clause 6a.12; in particular, the SCC AS checks UE-1 is eligible to request session replication for UE under the same subscription.

3. SCC AS sends Session Replication request to controllee UE-2.

4. UE-2 responses to the Session Replication request.

5. UE-2 initiates a new session with the remote UE. When the new session is established, the state of the original media is replicated, e.g. same playback state, same used media, etc. is replicated. If the remote party does not support setting up a replicated session, the flow will fail.

NOTE: The session replication data and how it is conveyed from the source UE is not specified in this document.

6. A new session, where the media are replica of Media-A, is established between UE-2 and the remote UE.

6a.11.3 Session replication initiated by source UE (different subscription)

Figure 6a.11.3-1: Session replication initiated by source UE, different subscriptions

1. UE-1 requests to replicate current session to UE-2 by sending Session Replication Request to SCC AS-1. The Session Replication Request should contain enough information for the SCC AS to:

– identify that the session replication source is UE-1;

– identify that the session replication target is UE-2;

– identify the remote party.

2. SCC AS-1 identify UE-2 is not under the same subscription as UE-1. It forwards the request to S-CSCF-2 that serves UE-2 together with the information of session on UE-1. S-CSCF-2 further forwards the request to SCC AS-2 that serves UE-2.

3. SCC AS-2 performs authorization as specified in clause 6a.12, then sends Session Replication request together with UE-1 session information to UE-2.

4. UE-2 decides to accept or reject the Session Replication request.

5. If the request is accepted by UE-2, UE-2 initiates a new session with the remote UE. When the new session is established, the state of the original media is replicated, e.g., same playback state, same used media, etc. is replicated.

NOTE 1: If either UE-2 or the remote party does not support setting up a replicated session, the flow will fail.

NOTE 2: The session replication data and how it is conveyed from the source UE is not specified in this document.

6. SCC AS-2 sends Media Replication result to UE-1. A new session, where the media are replica of Media-A, is established between UE-2 and the remote UE.

6a.11.4 Session replication initiated by target UE (different subscription)

The call flow in the figure below shows the scenario where UE-2 requests replication of a session ongoing between UE-1 and a remote UE. UE-1 and UE-2 belongs to different subscriptions. After the replication procedure is complete, the sessions are independent.

Figure 6a.11.4-1: Session replication initiated by target UE, different subscriptions

1. UE-2 obtains information about the existing sessions and their media flows. This information will be sent by the AS serving UE-1 i.e. SSC AS-1 and relayed to UE-1 by SCC AS-2.

2. UE-2 uses the session information obtained and to send a session replication request towards the SCC AS-2, which relays the request to SCC AS-1. The request indicates that this request is for a session replication request.

3. The SCC AS-1 performs authorization as specified in clause 6a.12; in particular, the SCC AS-1 requests UE-1 to authorize the replication request or the SCC AS-1 authorizes the request on behalf of UE-1 (e.g. pre-configured).

NOTE: The session replication data and how it is conveyed from the source UE is not specified in this document.

5. A new session, where the media is a replica of Media-A, is established between UE-2 and the remote UE.