6.2.13 Floor Control

23.3333GPPMultimedia Resource Function Controller (MRFC) - Multimedia Resource Function Processor (MRFP) Mp interface: Procedures descriptionsRelease 17TS

6.2.13.1 General

Floor control offers control of shared conference resources at the MRFP(s). Floor control protocol (BFCP) is used to convey the Floor control messages between the Floor Chair of the conference, the Floor Control Server, and the Floor Participants of the conference. All Floor control messages go via the Floor Control Server. Processing (granting or rejecting) Floor control requests is done by the one or more Floor chairs or by the FCS itself, depending on the Floor Control Policy.

The location of the Floor Control Server may be in either the MRFC or the MRFP depending on the complexity/distribution of the conference. However when located in the MRFP, the MRFP shall forward the Floor request decision to the MRFC in order to execute the changes to the Floor Participant’s granted permissions.

6.2.13.2 Floor Control within the MRFP

6.2.13.2.1 Floor Control Connection Establishment

The set of data to establish a BFCP connection shall be exchanged in accordance with IETF RFC 4583 [21]. A Floor control connection, which requires a BFCP/TCP protocol termination property, shall be established between the UE and the Floor Control Server, located in the MRFP. The MRFC shall initiate the "Configure BFCP Termination" procedure as specified in clause 8.44 to indicate to the MRFP the remote Floor control Client connection address and request the local Floor control Client connection address. The MRFP shall return the local Floor control Client connection address to the MRFC. The Floor control connection may be initiated by the UE or the MRFP (FCS).

– It is a prerequisite that the conference is configured using "Configure Conference for Floor Control" procedure as described in clause 6.2.13.2.2, which is used to set the common data of the conference for Floor control.

The combined sequence is shown in Figure 6.2.13.2.1.1

Figure 6.2.13.2.1.1: Combined procedures to Configure Conference and add a Floor Control Termination

6.2.13.2.2 Configure Conference and Floor Control Policy Indication

The "Configure Conference For Floor Control" procedure, specified in Clause 8.45 shall be used to set up a conference and to modify FCS properties such as the Floor Control Policy. The procedure defines common data for all BFCP users, these properties are defined on Context level.

The common data include:

– Floor-Resource Associations, which indicates the correlation between Floor ID and media properties for the MRFP to identify the Floor(s) when receiving BFCP requests and notifying the MRFC of decisions to change the floor permissions for a given user (termination).

– Conference Identifier, which indicates the Conference Identifier for the BFCP client to identify the conference when sending BFCP requests.

Floor Control Policy. This consists of:

– The Floor control algorithm to be used in granting the Floor, either:

– The FCFS algorithm or

– The chair-controlled algorithm.

– The maximum number of users who can hold the Floor at the same time.

Figure 6.2.13.2.2.1 shows the message sequence chart example for configuring a conference for Floor control.

Figure 6.2.13.2.2.1 Procedure to Configure Conference for Floor Control

6.2.13.2.3 Floor Chair Designation

If the Floor Control Policy indicates that the conference is Chair-controlled, the MRFC shall indicate to the MRFP which termination represents the Floor Chair and which Floor(s) the Floor Chair controls using the "Designate Floor Chair" procedure as specified in clause 8.46.

The MRFC may also change the Floor Chair as needed using the "Designate Floor Chair" procedure as specified in clause 8.46.

NOTE: There may be one or more Floor Chairs in a conference. But one media stream can be controlled by only one chair.

It is a prerequisite that the conference is configured and the termination configured for BFCP using "Configure Conference for Floor Control" and "Configure BFCP Termination" procedures respectively.

NOTE: These procedures may be requested at same time.

Figure 6.2.13.2.3.1 shows the message sequence chart example for designating Floor Chair.

Figure 6.2.13.2.3.1 Procedure to designate Floor Chair

6.2.13.2.4 Floor Request Decision

The MRFC shall request the MRFP to notify the decision of Floor request using the "Floor Decision Request" procedure as specified in clause 8.47. The MRFP shall then notify the MRFC the outcome of the Floor Request, when the FCS has made the decision to change the status to "Granted", " Released " or " Revoked " ( The status is defined as REQUEST-STATUS in IETF RFC 4582[20]), using the "Report Floor Status Decision" procedure as specified in clause 8.48.

The Floor Request Decision information is used by the MRFC to decide how to set the media properties of the associated Termination/Stream on the MRFP.

The MRFP shall indicate the Floor Identity or Identities to which the Floor decision is associated. The MRFP sends one notification per Floor decision for a given termination and only one notification per termination shall be outstanding at any time.

Figure 6.2.13.2.4.1 shows the message sequence chart example for requesting and reporting Floor Request decisions.

Figure 6.2.13.2.4.1 Procedure to request and report Floor Request decisions

6.2.13.2.5 Media Update and Confirmation

The MRFC modifies media properties associated with the Floor Request Decision received from the MRFP using the "Modify Media" procedure defined in Clause 8.59; this will be either adding permissions if the "status" was granted or removing the permissions if the "status" was revoked or released. The MRFC shall indicate to the MRFP when it has successfully modified the media properties based on the provided Floor Request Decisions notification using the "Confirm Media Update " procedure as specified in clause 8.49. The MRFP shall then modify the Floor status of the associated Client.

Figure 6.2.13.2.5.1 shows the message sequence chart example for modifying the media and confirming media update based on Floor Request status.

Figure 6.2.13.2.5.1 Procedures to modify the media and confirm media update

6.2.13.2.6 Floor Control Procedure

A Floor Participant may request one or more Floors by sending a BFCP request message to the MRFP (FCS).

The MRFP (FCS) informs the Floor Chair, if present, about a Floor Participant’s Floor request via BFCP.

The Floor Chair sends to the MRFP (FCS) the decision to the Floor Participant’s Floor requests. If the Floor is not Chair-controlled, the FCS located in the MRFP shall make the decision itself according to the Floor Control Algorithm.

The MRFP shall notify the MRFC the Floor change request decision via the "Report Floor Request Decision" procedure described in Clause 6.2.13.2.4.

The MRFC requests the MRFP to modify the media properties associated with the Floor Request decision as described in Clause 6.2.13.2.5.

The MRFC informs the MRFP that the requested media changes to satisfy the new Floor permissions have been completed using the "Confirm Media Update" procedure, see Clause 8.49.

The MRFC may request the MRFP to play tones or announcements for indicating when a user gains or loses Floor permissions.

6.2.13.2.7 Floor Control Connection Release

When the MRFC receives an indication that the Floor control connection is to be closed, the MRFC shall command the MRFP to release the Floor control connections.

The Floor control connection shall also be released by the MRFP when the termination for that connection is removed.

The Floor related BFCP signalling resources are released by the MRFP when the Floor control connection is released.

If a Floor Participant owns a Floor when releasing the Floor control connection, the MRFP(FCS) shall revoke the Floor permission.

6.2.13.2.8 Example Message sequence chart

Figure 6.2.13.1 shows the message sequence chart example for Floor control on a termination which is not the Floor Chair.

Figure 6.2.13.1 Floor control (message sequence chart)