11 Configurable parameters

24.3803GPPMission Critical Push To Talk (MCPTT) media plane controlProtocol specificationRelease 18TS

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

11.1 Timers

11.1.1 Timers in the on-network floor participant

The table 11.1.1-1 recommends timer values, describes the reason for starting the timer, normal stop and the action on expiry for the on-network floor participant procedures.

Table 11.1.1-1: Timers in the on-network floor participant

Timer	Timer value	Cause of start	Normal stop	On expiry
T100 (Floor Release)	Configurable as specified in 3GPP TS 24.483 [4]. (NOTE 1)	When the floor participant sends a Floor Release message.	Reception of a Floor Idle message or when the floor participant detects the receipt of RTP media.	If the counter is less than the upper limit of C100, a new Floor Release message is sent and counter is incremented by 1. When the limit in C100 is reached, the floor participant stops sending the Floor Release message.
T101 (Floor Request)	Configurable as specified in 3GPP TS 24.483 [4]. (NOTE 2)	When the floor participant sends a Floor Request message. T101 is also started when the application layer and signalling plane initiates a session as an implicit floor request using the "mc_implicit_request" as specified in clause 14.	Reception of a Floor Granted message, a Floor Taken message, or a Floor Deny message, a Floor Queue Position Info message	When T101 expires, a new Floor Request message is sent.
T103 (end of RTP media)	Should be equal to T1. Configurable as specified in 3GPP TS 24.483 [4].	Reception of a Floor Taken message or an RTP media packet. T103 is reset and started again every time an RTP media packet is received.	The reception of a Floor Idle message.	When T103 expires the floor control client concludes that the RTP media, which it was started for, has completed.
T104 (Floor Queue Position Request)	Configurable as specified in 3GPP TS 24.483 [4]. T104 shall only permit a certain number of retransmissions of the Floor Queue Position Request message.	When the floor participant sends a Floor Queue Position Request message.	Reception of a Floor Queue Position Info message. Leaving the ‘U: queued’ state.	If the counter is less than the upper limit of C104, a new Floor Queue Position Request message is sent and counter is incremented by 1. When the limit in C104 is reached, the floor participant stops sending the Floor Queue Position Request message.
T132 (Queued granted user action)	Default value: 2 seconds. Configurable as specified in 3GPP TS 24.483 [4].	When the floor participant receives a Floor Granted message for a queued request.	When a floor participant in ‘U: queued’ state pushes PTT button.	The floor participant sends a Floor Release message and may indicate to the user that the floor is no more available
T134 (Queued Floor Requests)	Default value: 2 seconds. Shall be implementation specific and based on local policies	When the floor participant sends the Queued Floor Requests message.	On receiving Queued Floor Requests message with an appropriate Purpose field.	Shall indicate to the user and action can be implementation specific.
NOTE 1: The total time during which the floor participant retransmits the Floor Release messages shall be less than 6 seconds. NOTE 2: The total time during which the floor participant retransmits Floor Request messages should be less than 6 seconds.

11.1.2 Timers in the off-network floor participant

The table 11.1.2-1 recommends timer values, describes the reason for starting the timer, normal stop and the action on expiry for the off-network floor participant procedures.

Table 11.1.2-1: Timers in the off-network floor participant

Timer	Timer value	Cause of start	Normal stop	On expiry
T201 (Floor Request)	Default value: 40 milliseconds Depends on the characteristic of the D2D. (D2D Side link period) Configurable. Set to the value of "/<x>/OffNetwork/Timers/T201" leaf node present in the UE initial configuration as specified in 3GPP TS 24.483. [4] T201 shall permit only a certain number of retransmissions of the Floor Request message.	When the floor participant sends a Floor Request message.	Reception of a Floor Granted message or a Floor Deny message or a Floor Queue Position Info message or when the MCPTT user releases the PTT button.	If the counter is less than the upper limit of C201, a new Floor Request message is sent and counter is incremented by 1. When the limit in C201 is reached, the floor participant stops sending the Floor Request message.
T203 (End of RTP media)	Default value: 4 seconds. Maximum value: 6 seconds. Configurable. Set to the value of "/<x>/OffNetwork/Timers/T203" leaf node present in the UE initial configuration as specified in 3GPP TS 24.483 [4].	When the floor participant receives an RTP media packet. T203 is also reset and started again every time an RTP media packet is received or when the floor participant enters ‘O: has no permission’	Reception of a Floor Release message or a Floor Granted to me or when the floor participant enters ‘O: has permission’	When T203 expires the floor participant concludes that there is no floor arbitrator at present.
T204 (Floor Queue Position Request)	Default value: 80 milliseconds. Depends on the characteristic of the D2D. (D2D Side link period*2). T204 shall permit only a certain number of retransmissions of the Floor Queue Position Request message. Configurable. Set to the value of "/<x>/OffNetwork/Timers/T204" leaf node present in the UE initial configuration as specified in 3GPP TS 24.483 [4].	When the floor participant sends a Floor Queue Position Request message.	Reception of the Floor Queue Position Info message.	If the counter is less than the upper limit of C204, a new Floor Queue Position Request message is sent and counter is incremented by 1. When the limit in C204 is reached, the floor participant stops sending the Floor Queue Position Request message.
T205 (Floor Granted)	Default value: 80 milliseconds. Depends on the characteristic of the D2D. (D2D Sidelink period*2). Configurable. Set to the value of "/<x>/OffNetwork/Timers/T205" leaf node present in the UE initial configuration as specified in 3GPP TS 24.483 [4]. T205 shall permit only a certain number of retransmissions of the Floor Granted message.	When the floor arbitrator grants the permission to send media to a floor participant, which was a pre-empting floor request or was in its queue when the PTT button was released.	Reception of an RTP media packet from granted floor participant in ‘O: pending granted’	If the counter is less than the upper limit of C205, a new Floor Granted message is sent and counter is incremented by 1. When the limit in C205 is reached, the floor arbitrator stops sending the Floor Granted message.
Timer T206 (Stop talking warning)	Default value: 27 seconds. Configurable. Set to X-Y, where X is the value of "/<x>/OffNetwork/TransmitTimeout" and Y is the value "/<x>/OffNetwork/TransmissionWarning" of leaf nodes present in the UE service configuration as specified in 3GPP TS 24.483 [4].	When the MCPTT client starts sending the RTP media packets.	When the MCPTT user releases the PTT button.	Start timer T207 (Stop talking)
Timer T207 (Stop talking)	Default value: 3 seconds. Configurable. Set to the value of "/<x>/OffNetwork/TransmissionWarning" leaf node present in the service configuration as specified in 3GPP TS 24.483 [4].	Expiry of timer T206 (Stop talking warning)	When the MCPTT user releases the PTT button.	If the value of "/<x>/<x>/OffNetwork/QueueUsage" leaf node present in the group configuration as specified in 3GPP TS 24.483 [4] is set to "true" and queue is not empty, grant to the next MCPTT user in the queue. Otherwise, release the floor.
T230 (Inactivity)	Default value: 600 seconds. Value should be more than T203. Configurable. For group calls: Set to the value of "/<x>/<x>/OffNetwork/HangTime" leaf node present in the group configuration as specified in 3GPP TS 24.483 [4]. For private calls: Set to the value of "/<x>/OffNetwork/PrivateCall/HangTime" leaf node present in the service configuration as specified in 3GPP TS 24.483 [4].	When the floor participant enters ‘O: silence’ state.	A floor control message or media is received.	The floor control entity is released.
T233 (Pending user action)	Default value: 3 seconds. Maximum value: 5 seconds. Configurable. Set to the value of "/<x>/OffNetwork/Timers/T233" leaf node present in the UE initial configuration as specified in 3GPP TS 24.483 [4] The total time (T205*C205+ T233) during which the floor arbitrator retransmits Floor Granted message and waits for user to accept floor should be less than T203.	Reception/Transmission of Floor Granted message for a queued request.	When a floor participant in ‘O: queued’ state pushes PTT button. Reception of RTP media packet from granted floor participant in ‘O: pending granted’	Assume the participant is out of coverage or does not want to speak anymore. Grant to next in queue if any, otherwise assume silence.

11.1.3 Timers in the floor control server

The table 11.1.3-1 recommends timer values, describes the reason for starting the timer, normal stop and the action on expiry for the floor control server procedures.

Table 11.1.3-1: Timers in the floor control server.

TIMER	TIMER VALUE	CAUSE OF START	NORMAL STOP	ON EXPIRY
T1 (End of RTP media)	Default value: 4 seconds Maximum value: 6 seconds. Configurable Obtained from the <T1-end-of-rtp-media> element of the <fc-timers-counters> element of the <on-network> element in 3GPP TS 24.484 [13]. (NOTE 1, NOTE 2)	Transmission of either a SIP message that includes an optional "mc_granted" fmtp attribute, or a Floor Granted message to the floor participant that are given permission to send media or when RTP media packets are received.	When the floor is released.	When T1 expires it is concluded that the granted floor request has been completed.
T2 (Stop talking)	Default maximum value: 30 seconds. Configurable. Obtained from the <time-limit> element of the <transmit-time> element of the <on-network> element in 3GPP TS 24.484 [13].	Detection of an RTP media packet. (NOTE 4)	Detection of the completion of media.	When T2 expires, it is concluded that the floor participant that has permission to send RTP media has talked too long.
T3 (Stop talking grace)	Default value: 3 seconds or 0 seconds if group is configured for audio cut-in obtained from the < mcptt-on-network-audio-cut-in> element of the <list-service> element of the group document as in 3GPP TS 24.481 [12]. Configurable. Obtained from the <T3-stop-talking-grace> element of the <fc-timers-counters> element of the <on-network> element in 3GPP TS 24.484 [13].	Expiry of T2.	Reception of a Floor Release message from the floor participant that has permission to send media.	When T3 expires, no more RTP media is allowed and that the floor is idle.
T4 (Inactivity)	Default value: 30 seconds. Configurable. For private calls: Obtained from the <hang-time> element of the <on-network> element in 3GPP TS 24.484 [13]. For group calls: Obtained from the <on-network-hang-timer> element of the <list-service> element in 3GPP TS 24.481 [12].	When the floor control server enters the ‘G: ‘Floor idle’ state.	A floor participant requests the permission to send media.	The MCPTT call is released.
T7 (Floor Idle)	Depends on the characteristic of the radio access network. Configurable. Obtained from the <T7-floor-idle> element of the <fc-timers-counters> element of the <on-network> element in 3GPP TS 24.484 [13].	The transmission of a Floor Idle message to the floor participants in the MCPTT call.	The stop can be supervised by a timer (out of scope of this specification). The recommended value of this timer is the same value as the value of the T15 (conversation) timer.	When T7 expire the floor control server sends another Floor Idle message to the floor participants.
T8 (Floor Revoke)	Default value: 1 second. Configurable. Obtained from the <T8-floor-revoke> element of the <fc-timers-counters> element of the <on-network> element in 3GPP TS 24.484 [13].	A Floor Revoke message is sent to a floor participant with the permission to send media.	Expiry of T3 or reception of a Floor Release message from the revoked floor participant.	Send another Floor Revoke message to the floor participant and reset and start T8 again.
T11 (End of RTP dual)	Default value: 4 seconds. Maximum value: 6 seconds. Configurable Obtained from the <T11-end-of-rtp-dual> element of the <fc-timers-counters> element of the <on-network> element in 3GPP TS 24.484 [13]. (NOTE 1)	When floor is granted to to the overriding MCPTT client. T11 is restarted each time an RTP packet is received from the overriding MCPTT client.	When the floor is released.	When T11 expires it is concluded that the granted overriding floor has been completed
T12 (Stop talking dual)	Default maximum value: 30 seconds. Configurable. Obtained from the <T12-stop-talking-dual> element of the <transmit-time> element of the <on-network> element in 3GPP TS 24.484 [13].	Detection of an RTP media packet of the overriding MCPTT client if not already running.	Detection of the completion of media of the overriding MCPTT client.	When T12 expires it is concluded that the overriding MCPTT client has talked too long.
T20 (Floor Granted)	Default value: 1 second. Configurable. Obtained from the <T20-floor-granted> element of the <fc-timers-counters> element of the <on-network> element in 3GPP TS 24.484 [13] (NOTE 3)	When the floor control server grants the permission to send media to a floor participant, which was queued and which negotiated queueing. T20 is also started again when the floor control server sends a Floor Granted message upon T20 expiry.	Reception of an RTP Media packet or when the MCPTT client is losing its permission to send media.	When T20 expires, a new Floor Granted message is sent unless the total time as limited by T1 is reached.
NOTE 1: The minimum value (Min) should be greater than the expected round trip delay from floor control server to the remote floor participant. Special consideration should be given to over-the-air connections that introduce significant transmission latency due to low bandwidth. NOTE 2: T1 can be set to higher value than normally when a queued MCPTT client is granted the permission to send media. NOTE 3: T20 shall only permit a certain number of retransmissions of the Floor Granted message. The total time during which the floor control server retransmits the Floor Granted messages is limited by T1. NOTE 4: T2 is not started in the case of an ambient listening call.

11.1.4 Timers in the participating MCPTT function

The table 11.1.4-1 and table 11.1.4-2 recommends timer values, describes the reason for starting the timer, normal stop and the action on expiry.

Table 11.1.4-1 shows the timers used in the call over pre-established session procedures in the participating MCPTT function.

Table 11.1.4-1: Timers in the participating MCPTT function for pre-established session control.

TIMER

TIMER VALUE

CAUSE OF START

NORMAL STOP

ON EXPIRY

T55

(Connect)

Default value:

2 seconds.

Maximum value:

4 seconds.

Configurable.

Obtained from the <T55-connect> element of the <fc-timers-counters> element of the <on-network> element in 3GPP TS 24.484 [13].

Transmission of ‘Connect’ message by the participating MCPTT function.

Reception of an Acknowledgement to the Connect message.

On the expiry of this timer less than a configurable number of times the ‘Connect’ message is resent.

T56

(Disconnect)

Default value:

2 seconds.

Maximum value:

4 seconds.

Configurable.

Obtained from the <T56-disconnect> element of the <fc-timers-counters> element of the <on-network> element in 3GPP TS 24.484 [13].

Transmission of ‘Disconnect’ message by the participating MCPTT function.

Reception of an Acknowledge message to the Disconnect message.

On the expiry of this timer less than a configurable number of times the ‘Disconnect’ message is resent.

Table 11.1.4-2 shows the timers used in the participating MCPTT function for MBMS channel control.

Table 11.1.4-2: Timers in the participating MCPTT function for MBMS channel control.

TIMER	TIMER VALUE	CAUSE OF START	NORMAL STOP	ON EXPIRY
T15 (Conversation)	Default value: 30 seconds. Configurable. Obtained from the <T15-conversation> element of the <fc-timers-counters> element of the <on-network> element in 3GPP TS24.484 [13].	Transmission of Map Group To Bearer message. Restarted when an RTP packet or a floor control message is sent.	Release of the call.	Send Unmap Group To Bearer message.
T16 (Map Group To Bearer)	Default value: 500 milliseconds. Configurable. Obtained from the <T16-map-group-to-bearer> element of the <fc-timers-counters> element of the <on-network> element in 3GPP TS 24.484 [13].	Transmission of Map Group To Bearer message.	Release of the call (or MBMS Subchannel).	Send Map Group To Bearer message.
T17 (Unmap Group To Bearer)	Default value: 200 milliseconds. Configurable. Obtained from the <T17-unmap-group-to-bearer> element of the <fc-timers-counters> element of the <on-network> element in 3GPP TS 24.484 [13].	Transmission of Unmap Group To Bearer message.	Release of the call.	Send Unmap Group To Bearer message.

11.2 Counters

11.2.1 Counters in the on-network floor participant

Table 11.2.1-1 enlists counters, their limits and the action on expiry.

Table 11.2.1-1: Counter used in the floor participant for on-network floor control

Counter	Limit	Associated timer	On reaching the limit
C100 (Floor Release)	Default value: 3	T100 (Floor Release)	Floor Release message is no more repeated
C101 (Floor Request)	Default value: 3	T101 (Floor Request)	Floor Request message is no more repeated
C104 (Floor Queue Position Request)	Default value: 3	T104 (Floor Queue Position Request)	Floor Queue Position Request message is no more repeated

11.2.2 Counters in the off-network floor participant

The table 11.2.2-1 lists the counters used by the off-network participant, their default upper limits and the action to take upon reaching the upper limit. The counters start at 1.

Table 11.2.1.2-1: Counter used in the floor participant for off-network floor control

Counter	Upper Limit	Associated timer	Upon reaching the upper limit
C201 (Floor Request)	Default value: 3. Configurable. Set to the value of "/<x>/OffNetwork/Counters/C201" leaf node present in the UE initial configuration as specified in 3GPP TS 24.483 [4].	T201 (Floor Request)	Assume there is no floor arbitrator and send Floor Taken message
C204 (Floor Queue Position Request)	Default value: 3. Configurable. Set to the value of "/<x>/OffNetwork/Counters/C204" leaf node present in the UE initial configuration as specified in 3GPP TS 24.483 [4].	T204 (Floor Queue Position Request)	Floor Queue Position Request message is no more repeated
C205 (Floor Granted)	Default value: 4. Configurable. Set to the value of "/<x>/OffNetwork/Counters/C205" leaf node present in the UE initial configuration as specified in 3GPP TS 24.483 [4].	T205 (Floor Granted)	If there is a pending request(s) in the queue, start timer T233 (pending user action) and wait for RTP media from the client.

Counter

Upper Limit

Associated timer

Upon reaching the upper limit

C201

(Floor Request)

Default value: 3.

Configurable.

Set to the value of "/<x>/OffNetwork/Counters/C201" leaf node present in the UE initial configuration as specified in 3GPP TS 24.483 [4].

T201 (Floor Request)

Assume there is no floor arbitrator and send Floor Taken message

C204

(Floor Queue Position Request)

Default value: 3.

Configurable.

Set to the value of "/<x>/OffNetwork/Counters/C204" leaf node present in the UE initial configuration as specified in 3GPP TS 24.483 [4].

T204 (Floor Queue Position Request)

Floor Queue Position Request message is no more repeated

C205 (Floor Granted)

Default value: 4.

Configurable.

Set to the value of "/<x>/OffNetwork/Counters/C205" leaf node present in the UE initial configuration as specified in 3GPP TS 24.483 [4].

T205 (Floor Granted)

If there is a pending request(s) in the queue, start timer T233 (pending user action) and wait for RTP media from the client.

11.2.3 Counters in the controlling MCPTT function

The table 11.2.3-1 enlists counters, their limits and the action on expiry for the ‘general control operation’ state machine in the controlling MCPTT function.

Table 11.2.3-1: Counters used in the ‘general floor control operation’ state machine

Counter	Limit	Associated timer	On reaching the limit
C7 (Floor Idle)	Default value: 10. Configurable. Obtained from the <C7-floor-idle> element of the <fc-timers-counters> element of the <on-network> element in 3GPP TS 24.484 [13].	T7 (Floor Idle)	The Floor Idle message is no more re-send
C20 (Floor Granted)	Default value: 3. Configurable. Obtained from the <C20-floor-granted> element of the <fc-timers-counters> element of the <on-network> element in 3GPP TS 24.484 [13].	T20 (Floor Granted)	The Floor Granted message is no more re-send in case a queued floor participant is granted the floor.
NOTE: If a counter value is not configured the default value shall be used.

Counter

Limit

Associated timer

On reaching the limit

(Floor Idle)

Default value: 10.

Configurable.

Obtained from the <C7-floor-idle> element of the <fc-timers-counters> element of the <on-network> element in 3GPP TS 24.484 [13].

T7 (Floor Idle)

The Floor Idle message is no more re-send

C20

(Floor Granted)

Default value: 3.

Configurable.

Obtained from the <C20-floor-granted> element of the <fc-timers-counters> element of the <on-network> element in 3GPP TS 24.484 [13].

T20 (Floor Granted)

The Floor Granted message is no more re-send in case a queued floor participant is granted the floor.

NOTE: If a counter value is not configured the default value shall be used.

11.2.4 Counters in the participating MCPTT function

The table 11.2.4-1 enlists counters, their limits and the action on expiry for the ‘pre-established session state machine’.

Table 11.2.4-1: Counters used in the ‘pre-established session state machine’

Counter	Limit	Associated timer	On reaching the limit
C55 (Connect)	Default value: 3. Configurable. Obtained from the <C55-connect> element of the <fc-timers-counters> element of the <on-network> element in 3GPP TS 24.484 [13].	T55 (Connect)	The Connect message is no more re-send
C56 (Disconnect)	Default value: 3. Configurable. Obtained from the <C56-disconnect> element of the <fc-timers-counters> element of the <on-network> element in 3GPP TS 24.484 [13].	T56 (Disconnect)	The Disconnect message is no more re-send

Counter

Limit

Associated timer

On reaching the limit

C55

(Connect)

Default value: 3.

Configurable.

Obtained from the <C55-connect> element of the <fc-timers-counters> element of the <on-network> element in 3GPP TS 24.484 [13].

T55 (Connect)

The Connect message is no more re-send

C56

(Disconnect)

Default value: 3.

Configurable.

Obtained from the <C56-disconnect> element of the <fc-timers-counters> element of the <on-network> element in 3GPP TS 24.484 [13].

T56 (Disconnect)

The Disconnect message is no more re-send

The table 11.2.4-2 enlists counters, their limits and the action on expiry for the ‘Participating MCPTT function MBMS subchannel control state machine’.

Table 11.2.4-2: Counters used in the ‘Participating MCPTT function MBMS subchannel control state machine’

Counter	Limit	Associated timer	On reaching the limit
C17 (Unmap Group To Bearer)	Default value: 3. Configurable. Obtained from the <C17-unmap-group-to-bearer> element of the <on-network> element in 3GPP TS24.484 [13].	T17 (Unmap Group To Bearer)	The Unmap Group To Bearer message is no more re-sent.

Counter

Limit

Associated timer

On reaching the limit

C17

(Unmap Group To Bearer)

Default value: 3.

Configurable.

Obtained from the <C17-unmap-group-to-bearer> element of the <on-network> element in 3GPP TS24.484 [13].

T17 (Unmap Group To Bearer)

The Unmap Group To Bearer message is no more re-sent.