11.1.2 Private call without floor control and first-to-answer call without floor control

24.3793GPPMission Critical Push To Talk (MCPTT) call controlProtocol specificationRelease 18TS

11.1.2.1 General

Clause 11.1.2 specifies the MCPTT client procedures, participating MCPTT function procedures and controlling MCPTT function procedures for on-network private calls without floor control and first-to-answer calls without floor control. The procedures in clause 11.1.2 refer to the on-network private calls with floor control procedures and first-to-answer calls with floor control procedures in clause 11.1.1 citing the differences.

11.1.2.2 MCPTT client procedures

When the MCPTT user wants to make an on-demand private call without floor control or first-to-answer call without floor control, the MCPTT client shall follow the procedures in clause 11.1.1.2.1.1 with the following exceptions:

1) in step 12) of clause 11.1.1.2.1.1, the MCPTT client shall not offer a media-level section for a media-floor control entity; and

2) step 13) of clause 11.1.1.2.1.1 shall be ignored.

When the MCPTT user wants to make a private call without floor control or first-to-answer call without floor control using a pre-established session, the MCPTT client shall follow the procedures in clause 11.1.1.2.2.1 with the following exceptions:

1) step 8 c) i) is re-written as: if the SDP parameters of the pre-established session contain a media-level section of a media-floor control entity or if end-to-end security is required for the private call, an application/sdp MIME body containing the SDP parameters of the pre-established session according to 3GPP TS 24.229 [4] with the clarifications given in clause 6.2.1. If the pre-established session was established with implicit floor control, then the application/sdp MIME body shall not contain the implicit floor request as specified in clause 6.4; and

2) step 9a) is re-written as: if the SDP parameters of the pre-established session contain a media-level section of a media-floor control entity, an application/sdp MIME body containing the SDP parameters of the pre-established session according to 3GPP TS 24.229 [4] with the clarifications given in clause 6.2.1. If the pre-established session was established with implicit floor control, then the application/sdp MIME body shall not contain the implicit floor request as specified in clause 6.4.

Upon receipt of an initial SIP INVITE request for the private call or first-to-answer call with an SDP offer not including a media-level section for a media-floor control entity, the MCPTT client shall consider it as the request for private call without floor control and shall follow the procedures as specified in clause 11.1.1.2.1.2 for on-demand session and clause 11.1.1.2.2.2 for pre-established session.

11.1.2.3 Participating MCPTT function procedures

11.1.2.3.1 Originating procedures

Upon receipt of a "SIP INVITE request for originating participating MCPTT function" for a private call or first-to-answer call with an SDP offer not including a media-level section for media plane control messages, the participating MCPTT function shall consider it as a request for a private call without floor control or first-to-answer call without floor control and shall follow the procedures as specified in clause 11.1.1.3.1.1 for an on-demand session.

Upon receipt of a "SIP REFER request for a pre-established session" for a private call or first-to-answer call with an SDP offer including a media-level section for media plane control messages with the ‘fmtp’ attribute containing a value of "mc_no_floor_ctrl" as specified in 3GPP TS 24.380 [5] clause 14, the participating MCPTT function shall consider it as a request for a private call without floor control or first-to-answer call without floor control and shall follow the procedures as specified in clause 11.1.1.3.1.2 for initiation using a pre-established session.

11.1.2.3.2 Terminating procedures

Upon receipt of a "SIP INVITE request for terminating participating MCPTT function" for the private call or first-to-answer call with SDP offer not including media-level section for media-floor control entity, the participating MCPTT shall consider it as the request for the private call without floor control or first-to-answer call without floor control and shall follow the procedures as specified in clause 11.1.1.3.2.

11.1.2.4 Controlling MCPTT function procedures

11.1.2.4.1 Originating procedures

The controlling MCPTT function shall follow the procedures as specified in clause 11.1.1.4.1.

11.1.2.4.2 Terminating procedures

Upon receiving of a "SIP INVITE request for controlling MCPTT function of a private call" or a "SIP INVITE request for controlling MCPTT function of a first-to-answer call", with SDP offer not including media-level section for media-floor control entity, the controlling MCPTT function shall consider it as the request for the private call without floor control or first-to-answer call without floor control, and shall follow the procedures as specified in clause 11.1.1.4.2.