Content for &nbsp; TS 23.379 &nbsp; Word version:&nbsp; 19.1.0

MCPTT users on MCPTT client 1 and MCPTT client 2 are already registered for receiving MCPTT service, as per procedure in subclause 10.2.

User at MCPTT client 1 would like to initiate an MCPTT private call for the chosen MCPTT user. The MCPTT user at MCPTT client 1 may include a functional alias used within the MCPTT private call. For a private call with floor control, floor control is to be established.

MCPTT client 1 sends an MCPTT private call request towards the MCPTT server (via SIP core) using a service identifier as defined in TS 23.228 for MCPTT, for establishing a private call with the chosen MCPTT user. The MCPTT private call request contains the MCPTT ID or the functional alias of the invited user, an SDP offer containing one or more media types. For a private call with floor control, the MCPTT private call request also contains an element that indicates that MCPTT client 1 is requesting the floor. The MCPTT client 1 may include a Requested commencement mode that indicates that the call is to be established in automatic commencement mode if automatic commencement mode is requested by the initiating user.

If the MCPTT private call request contains a functional alias instead of an MCPTT ID as called party, the MCPTT server shall resolve the functional alias to the corresponding MCPTT ID(s) for which the functional alias is active. The MCPTT server shall also check whether MCPTT client 1 is allowed to use the functional alias of MCPTT client 2 to setup a private call and whether MCPTT client 2 is allowed to receive a private call from MCPTT client 1 using the functional alias. If authorized, proceed with step 5. Otherwise, the MCPTT server checks whether the MCPTT user at MCPTT client 1 is authorized to initiate the private call, and that MCPTT user at MCPTT client 2 is authorized to receive the private call. If the MCPTT private call request requested automatic commencement mode then the MCPTT server also checks whether the MCPTT user at MCPTT client 1 is authorized to initiate a private call in automatic commencement mode and proceed with step 6.

NOTE 2:

Depending on implementation the MCPTT server can apply additional call restrictions and decide whether the call is allowed to proceed with the resolved MCPTT ID(s) (e.g. whether the MCPTT ID is within the allowed area of the functional alias). If the MCPTT server detects that the functional alias used as the target of the private call request is simultaneously active for multiple MCPTT users, then the MCPTT server can proceed by selecting an appropriate MCPTT ID based on some selection criteria (e.g. current location of the initiating user to determine the dispatcher who is responsible for the related geographic area). The selection of an appropriate MCPTT ID is left to implementation. This selection criteria can include rejection of the call, if no suitable MCPTT ID is selected.

Step 5a.

The MCPTT server responds with a functional alias resolution response message that contains the resolved MCPTT ID back to MCPTT client 1.

Step 5b.

If the MCPTT server replies with a MCPTT functional alias resolution response message, the MCPTT client 1 abandons the first MCPTT private call request in step 3 and sends a new MCPTT private call request towards the resolved MCPTT ID.

Figure 10.7.2.2.2.2-1: MCPTT private call in manual commencement mode- MCPTT users in the same MCPTT system

MCPTT server may provide a progress indication to MCPTT client 1 to indicate progress in the call setup process.

Step 7.

If authorized, MCPTT server includes information that it communicates using MCPTT service, offers the same media types or a subset of the media types contained in the initial received request, includes the requested automatic commencement mode indication based on a requested automatic commencement mode by the calling user or based upon the setting of the called MCPTT client and sends the corresponding MCPTT private call request towards the MCPTT client 2, including the MCPTT ID and, if available, the functional alias of the calling MCPTT user 1. If the called MCPTT user has registered to the MCPTT service with multiple MCPTT UEs and has designated the MCPTT UE for receiving the private calls, then the incoming MCPTT private call request is delivered only to the designated MCPTT UE.

Step 8.

The receiving MCPTT client 2 notifies the user about the incoming private call and displays the functional alias of calling MCPTT user 1.

Step 9.

The receiving MCPTT client 2 accepts the private call automatically, and an MCPTT private call response is sent to the MCPTT server (via SIP core).

Step 10.

Upon receiving the MCPTT private call response from MCPTT client 2 accepting the private call request, the MCPTT server informs the MCPTT client 1 about successful call establishment.

Step 11.

MCPTT client 1 and MCPTT client 2 have successfully established media plane for communication and either user can transmit media. For successful call establishment for private call with floor control request from MCPTT client 1, floor participant at MCPTT client 1 is granted floor by the floor control server, giving it permission to transmit. At the same time floor participant at MCPTT client 2 is informed by the floor control server that floor is taken.

10.7.2.2.2 Private call setup in manual commencement mode p. 117

10.7.2.2.2.1 Description p. 117

Figure 10.7.2.2.2.2-1 describes the basic procedure for the MCPTT client initiating an MCPTT private call that uses manual commencement mode. The flow may use a floor request in the MCPTT private call request indicating that the originator will be given the floor when the call starts and eliminates the need for a separate initial floor request message during media plane establishment. Alternatively the call initiation may be sent without the floor request, which allows the called party to request the floor first.

10.7.2.2.2.2 Procedure p. 117

Both clients are served by the primary MCPTT service provider in Figure 10.7.2.2.2.2-1.

Pre-conditions:

The calling MCPTT user has selected manual commencement mode or has not specified a commencement mode for the call; and
The called MCPTT client is set to manual commencement mode.
Optionally, MCPTT client 1 may use an activated functional alias for the call.
The MCPTT server has subscribed to the MCPTT functional alias controlling server within the MC system for functional alias activation/de-activation updates.

Reproduction of 3GPP TS 23.379, Fig. 10.7.2.2.2.2-1: MCPTT private call in manual commencement mode- MCPTT users in the same MCPTT system

MCPTT client 1 and MCPTT client 2 are both registered and their respective users, MCPTT user 1 and MCPTT user 2, are authenticated and authorized to use the MCPTT service, as per procedure in subclause 10.2.

MCPTT user at MCPTT client 1 would like to initiate an MCPTT private call for the selected MCPTT user. The MCPTT user at MCPTT client 1 may include a functional alias used within the MCPTT private call. For a private call with floor control, floor control is to be established. For private call without floor control, both users will have the ability to transmit without floor arbitration.

MCPTT client 1 sends an MCPTT private call request addressed to the MCPTT ID of MCPTT user 2 using an MCPTT service identifier as defined in TS 23.228 (possible for the SIP core to route the request to the MCPTT server). The MCPTT private call request contains the MCPTT ID or the functional alias of invited user and an SDP offer containing one or more media types. The MCPTT private call request may also contain a data element that indicates that MCPTT client 1 is requesting the floor, for a private call with floor control. The MCPTT client 1 may include a requested commencement mode that indicates that the call is to be established in manual commencement mode if manual commencement mode is requested by the initiating user.

The MCPTT server confirms that both MCPTT users are authorized for the private call. MCPTT server verifies whether the provided functional alias, if present, can be used and has been activated for the user. The MCPTT server shall resolve the functional alias to the corresponding MCPTT ID(s) for which the functional alias is active. The MCPTT server shall also check whether MCPTT client 1 is allowed to use the functional alias of MCPTT client 2 to setup a private call and whether MCPTT client 2 is allowed to receive a private call from MCPTT client 1 using the functional alias. The MCPTT server checks the commencement mode setting of the called MCPTT client and also checks whether the MCPTT user at MCPTT client 1 is authorized to initiate a call in manual commencement mode.

NOTE 2:

Step 5a.

If the MCPTT private call request contains a functional alias instead of an MCPTT ID as called party, the MCPTT server responds with a functional alias resolution response message that contains the resolved MCPTT ID back to MCPTT client 1.

Step 5b.

Figure 10.7.2.2.3.1-1: Private call release - client initiated

The MCPTT server includes information that it communicates using MCPTT service, offers the same media types or a subset of the media types contained in the initial received request and sends an MCPTT private call request for the call to MCPTT client 2, including the MCPTT ID and, if available, the functional alias of the calling MCPTT user 1. If the called MCPTT user has registered to the MCPTT service with multiple MCPTT UEs and has designated the MCPTT UE for receiving the private calls, then the incoming MCPTT private call request is delivered only to the designated MCPTT UE.

Step 7.

MCPTT server may provide a progress indication to MCPTT client 1 to indicate progress in the call setup process.

Step 8a.

The MCPTT user is alerted and may display the functional alias of calling MCPTT user 1. MCPTT client 2 sends an MCPTT ringing to the MCPTT server.

Step 8b.

The MCPTT server sends an MCPTT ringing to MCPTT client 1, indicating that MCPTT client 2 is being alerted.

Step 9.

MCPTT user 2 has accepted the call using manual commencement mode (i.e., has taken some action to accept via the user interface) which causes MCPTT client 2 to send an MCPTT private call response to the MCPTT server. If MCPTT user 2 has not accepted the incoming call, the MCPTT client 2 sends a call failure response to the MCPTT server without adding reason for call failure.

Step 10.

The MCPTT server sends an MCPTT private call response to MCPTT client 1 indicating that MCPTT user 2 has accepted the call, including the accepted media parameters.

Step 11.

The media plane for communication is established. Either user can transmit media individually when using floor control. For successful call establishment for private call with floor request from MCPTT client 1, the floor participant associated with MCPTT client 1 is granted the floor initially. At the same time the floor participant associated with MCPTT client 2 is informed that the floor is taken. The meaning of the floor request (give floor initially to originator [client 1], or give floor initially to target [client 2]) may be configurable. For a private call without floor control both users are allowed to transmit simultaneously.

10.7.2.2.3 Private call release p. 119

10.7.2.2.3.1 Client initiated p. 119

The procedure focuses on the case where an MCPTT client is requesting to release an ongoing MCPTT private call (with or without floor control) and the call established in either of the two commencement modes (manual or automatic).

Procedures in Figure 10.7.2.2.3.1-1 are the basic signalling control plane procedures for the MCPTT client initiating the release of an ongoing MCPTT private call.

Reproduction of 3GPP TS 23.379, Fig. 10.7.2.2.3.1-1: Private call release - client initiated

It is assumed that MCPTT users on MCPTT client 1 and MCPTT client 2 are already registered for receiving MCPTT service and are involved in private call with or without floor control established either in manual or automatic commencement mode, as described in subclause 10.7.2.2.1 and subclause 10.7.2.2.2.

User at MCPTT client 1 would like to release an ongoing MCPTT private call with MCPTT client 2.

MCPTT client 1 sends an MCPTT private call end request towards the MCPTT server (via SIP core), for tearing down the private call with the other client.

MCPTT server sends the corresponding MCPTT private call end request towards the MCPTT client specified in the original MCPTT private call end request.

Step 5.

MCPTT user is notified about the release of the private call.

Figure 10.7.2.2.3.2-1: End private call - server initiated

The receiving MCPTT client 2 acknowledges the MCPTT private call end request with an MCPTT private call end response.

Step 7.

After receiving the MCPTT private call end response from MCPTT client 2, the MCPTT server generates an acknowledgement for the MCPTT client 1's MCPTT private call end request.

Step 8.

MCPTT clients release all the media plane resources used for the private call. Further, if the private call was established with floor control, floor control resources are released and MCPTT clients cannot make further requests for floor control or send media.

10.7.2.2.3.2 Server initiated p. 120

The procedure focuses on the case where an MCPTT server is terminating an ongoing MCPTT private call (with or without floor control) and the call established in either of the two commencement modes (manual or automatic), upon conditions to terminate call e.g., MCPTT administrator configured maximum duration for MCPTT private calls has expired or timed out due to MCPTT private call without transmission/reception.

Procedures in Figure 10.7.2.2.3.2-1 are the basic signalling control plane procedures for the MCPTT server initiating termination of an ongoing MCPTT private call.

Reproduction of 3GPP TS 23.379, Fig. 10.7.2.2.3.2-1: End private call - server initiated

Upon conditions to terminate call e.g., MCPTT administrator configured maximum duration for MCPTT private calls has expired or timed out due to MCPTT private call without transmission/reception, the MCPTT server decides to initiate termination of an ongoing MCPTT private call between MCPTT client 1 and MCPTT client 2.

MCPTT server sends an MCPTT private call end request towards the MCPTT clients 1 and 2 (via SIP core), for tearing down the private call between them.

MCPTT users at client 1 and client 2 are notified about the termination of the private call.

Step 5.

The MCPTT private call end request receiving MCPTT clients 1 and 2 acknowledge the request with an MCPTT private call end response.