The MCPTT private call call-back request procedure includes the initial MCPTT private call call-back request from the MCPTT user and the indication to the receiving MCPTT user of the who called, the time when the call request was made, and the urgency indication.
Procedures in
Figure 10.7.4.2-1 show the signalling control plane procedures for the MCPTT client initiating an MCPTT private call call-back request with the chosen MCPTT user.
Pre-conditions:
-
MCPTT user 1 is the current user at MCPTT client 1 and MCPTT user 2 is the current user at MCPTT client 2;
-
MCPTT client 1 and MCPTT client 2 are registered for MCPTT service.
Step 1.
MCPTT user on MCPTT client 1 initiates an MCPTT private call call-back request to the MCPTT user of MCPTT client 2.
Step 2.
MCPTT client 1 sends an MCPTT private call call-back request towards the MCPTT server.
Step 3.
MCPTT server checks whether the MCPTT user 1 at MCPTT client 1 is authorized to initiate the MCPTT private call call-back request.
Step 4.
If authorized, MCPTT server sends the corresponding MCPTT private call call-back request towards the MCPTT client 2.
Step 5.
The receiving MCPTT client 2 stores the MCPTT user who initiated the MCPTT private call call-back request, the time the MCPTT private call call-back request was received, and the urgency indication for the MCPTT private call call-back request.
Step 6.
The MCPTT client 2 notifies the MCPTT user 2 that there is an MCPTT private call call-back request awaiting his attention.
Step 7.
The receiving MCPTT client 2 sends an MCPTT private call call-back response to the MCPTT server.
Step 8.
Upon receiving the MCPTT private call call-back response from MCPTT client 2, the MCPTT server informs the MCPTT client 1 about successful call-back request.
Once an MCPTT private call call-back request has been successfully made and before the receiving MCPTT user has made an MCPTT private call to the calling MCPTT user, the calling MCPTT user may cancel the outstanding MCPTT private call request.
Procedures in
Figure 10.7.4.3-1 show the signalling control plane procedures for the MCPTT client initiating an MCPTT private call call-back cancel request with the chosen MCPTT user.
Pre-conditions:
-
A previously successfully made MCPTT private call call-back request from MCPTT client 1 to MCPTT client 2.
Step 1.
MCPTT user on MCPTT client 1 wants to cancel a previously created MCPTT private call call-back request to the MCPTT user 2 of MCPTT client 2.
Step 2.
MCPTT client 1 sends an MCPTT private call call-back cancel request towards the MCPTT server.
Step 3.
MCPTT server checks whether the MCPTT user 1 at MCPTT client 1 is authorized to cancel the previous MCPTT private call call-back request, if one exists.
Step 4.
If authorized, MCPTT server sends the corresponding MCPTT private call call-back cancel request towards the MCPTT client 2.
Step 5.
The receiving MCPTT client 2 removes all stored information about the previous MCPTT private call call-back request from the MCPTT user 1 on MCPTT client 1.
Step 6.
The receiving MCPTT client 2 sends an MCPTT private call call-back cancel response to the MCPTT server.
Step 7.
Upon receiving the MCPTT private call call-back cancel response from MCPTT client 2, the MCPTT server informs the MCPTT client 1 about successful call-back request cancelation.
Once an MCPTT private call call-back request has been successfully made, it is expected that the receiving MCPTT user will make an MCPTT private call to the MCPTT user who sent the MCPTT private call call-back request. The procedures for establishing the MCPTT private call between the two users is the same as an MCPTT private call (10.7.2.2.2).
Procedures in
Figure 10.7.4.4-1 show the signalling control plane procedures for the MCPTT client returning an MCPTT private call to the MCPTT user who initiated the MCPTT private call call-back request.
Pre-conditions:
-
A previously successfully made MCPTT private call call-back request from MCPTT client 1 to MCPTT client 2.
Step 1.
MCPTT user 2 on MCPTT client 2 decides to initiate an MCPTT private call based on the stored MCPTT private call call-back request to the MCPTT user 1 on MCPTT client 1 using the MCPTT private call procedures of 10.7.2.2.2.
Step 2.
Once a successful MCPTT private call has been made between the MCPTT user 1 on MCPTT client 1 and MCPTT user 2, then the MCPTT client 2 removes the stored call-back request information.