8 M3AP Procedures

36.4443GPPEvolved Universal Terrestrial Radio Access Network (E-UTRAN)M3 Application Protocol (M3AP)Release 17TS

8.1 Elementary procedures

In the following tables, all EPs are divided into Class 1 and Class 2 EPs (see subclause 3.1 for explanation of the different classes):

Table 8-1: Class 1 procedures

Elementary Procedure

Initiating Message

Successful Outcome

Unsuccessful Outcome

Response message

Response message

MBMS Session Start

MBMS SESSION START REQUEST

MBMS SESSION START RESPONSE

MBMS SESSION START FAILURE

MBMS Session Stop

MBMS SESSION STOP REQUEST

MBMS SESSION STOP RESPONSE

MBMS Session Update

MBMS SESSION UPDATE REQUEST

MBMS SESSION UPDATE RESPONSE

MBMS SESSION UPDATE FAILURE

Reset

RESET

RESET ACKNOWLEDGE

M3 Setup

M3 SETUP REQUEST

M3 SETUP RESPONSE

M3 SETUP FAILURE

MCE Configuration Update

MCE CONFIGURATION UPDATE

MCE CONFIGURATION UPDATE ACKNOWLEDGE

MCE CONFIGURATION UPDATE FAILURE

Table 8-2: Class 2 procedures

Elementary Procedure

Message

Error Indication

ERROR INDICATION

The following applies concerning interference between Elementary Procedures:

– The Reset procedure takes precedence over all other EPs.

8.2 MBMS Session Start

8.2.1 General

The purpose of the MBMS Session Start procedure is to request the MCE to determine whether an MBMS E-RAB for an upcoming MBMS Session for a given MBMS Bearer Service can be accommodated by the E-UTRAN. The MCE is also requested to establish an MBMS service associated logical M3 connection. The MBMS Session Start procedure is triggered by the EPC (MME).

The procedure uses MBMS Service associated signaling.

8.2.2 Successful Operation

Figure 8.2.2-1: MBMS Session Start procedure. Successful operation.

The MME initiates the procedure by sending an MBMS SESSION START REQUEST message to the MCE.

If the MCE receives the MBMS SESSION START REQUEST message including the MBMS Cell List IE, the MCE may use it as defined in TS 36.300 [3].

In MBSFN operation

– The MCE shall use the information in the MBMS E-RAB QoS parameters IE to determine whether the requested configuration can be accommodated within E-UTRAN.

– If the Time of MBMS Data Transfer IE is included in the MBMS SESSION START REQUEST message, the MCE shall, if supported, take it into account for the synchronization of the corresponding MCCH Update instead of the Minimum Time to MBMS Data Transfer IE. The MCE shall ensure the eNB applies the MCCH update from the last modification period before the time indicated by the Time of MBMS Data Transfer IE.

In SC-PTM operation, the MCE shall forward the information in the MBMS E-RAB QoS parameters IE to the relevant eNBs.

If the MCE receives the MBMS SESSION START REQUEST message including the Re-establishment IE for a service which is already ongoing, it shall, if supported, accept this message and replace the MBMS context for that service (see TS 23.007 [14]).

If the MCE receives the MBMS SESSION START REQUEST message including the Alternative TNL Information IE, it may send the content of that IE to the eNB.

The MCE shall report to the MME, in the MBMS SESSION START RESPONSE message the result of the requested MBMS E-RAB.

In MBSFN operation, the MCE shall establish or modify the resources according to the values of the Allocation and Retention Priority IE (priority level and pre-emption indicators) and the resource situation as follows:

– The MCE shall consider the priority level of the requested session, when deciding on the resource allocation.

– The priority levels and the pre-emption indicators may (individually or in combination) be used to determine whether the session has to be started unconditionally and immediately. If the requested session is marked as “may trigger pre-emption” and the resource situation requires so, the MCE may trigger the pre-emption procedure which may then cause the forced release of a lower priority session which is marked as “pre-emptable”. Whilst the process and the extent of the pre-emption procedure is operator-dependent, the pre-emption indicators shall be treated as follows:

1. If the Pre-emption Capability IE is set to “may trigger pre-emption”, then this allocation request is allowed to trigger a pre-emption procedure.

2. If the Pre-emption Capability IE is set to “shall not trigger pre-emption”, then this allocation request is not allowed to trigger a pre-emption procedure.

3. If the Pre-emption Vulnerability IE is set to “pre-emptable”, then this session shall be included in the pre-emption process.

4. If the Pre-emption Vulnerability IE is set to “not pre-emptable”, then this session shall not be included in the pre-emption process.

5. If the Priority Level IE is set to “no priority”, the given values for the Pre-emption Capability IE and Pre-emption Vulnerability IE shall not be considered. Instead the values “shall not trigger pre-emption” and “not pre-emptable” shall prevail.

– The E-UTRAN pre-emption process shall keep the following rule: E-UTRAN shall only pre-empt sessions with lower priority, in ascending order of priority.

8.2.3 Unsuccessful Operation

Figure 8.2.3-1: MBMS Session Start procedure. Unsuccessful operation.

If the MCE determines that the E-UTRAN is not able to accommodate the requested configuration for any involved MBSFN area when using MBSFN transmission, or in any involved cell when using SC-PTM, the MME shall be informed by the MBMS SESSION START FAILURE message including a suitable cause value.

If the MCE receives MBMS SESSION START REQUEST message including the MBMS Cell List IE and the list includes no cell controlled by eNB with which the MCE has connection, the MME shall be informed by the MBMS SESSION START FAILURE message including a suitable cause value, e.g. “Un-involved MCE”.

8.2.4 Abnormal Conditions

Not applicable.

8.3 MBMS Session Stop

8.3.1 General

The purpose of the MBMS Session Stop procedure is to inform the MCE about the end of an ongoing MBMS Session for a given MBMS Bearer Service, and that the E-UTRAN releases the allocated MBMS E-RAB resources and that the associated MBMS service associated logical M3 connection is also released. The MBMS Session Stop procedure is triggered by the EPC (MME).

The procedure uses MBMS Service associated signaling.

8.3.2 Successful Operation

Figure 8.3.2-1: MBMS Session Stop procedure. Successful operation.

The MME initiates the procedure by sending an MBMS SESSION STOP REQUEST message to the MCE. Upon receipt of the MBMS SESSION STOP REQUEST message, the MCE shall send the MBMS SESSION STOP RESPONSE message after the MCE releases the affected resources and removes the MBMS bearer context.

If the Time of MBMS Data Stop IE is included in the MBMS SESSION STOP REQUEST message, the MCE shall, if supported, take it into account for the synchronization of the corresponding MCCH Update. The MCE shall ensure the eNB applies the MCCH update from the first modification period after the time indicated by the Time of MBMS Data Stop IE.

8.3.3 Unsuccessful Operation

Not applicable.

8.3.4 Abnormal Conditions

Not applicable.

8.4 Error Indication

8.4.1 General

The Error Indication procedure is initiated by a node to report detected errors in one incoming message, provided they cannot be reported by an appropriate failure message.

If the error situation arises due to reception of a message utilising MBMS-service-associated signalling, then the Error Indication procedure uses MBMS-service-associated signalling. Otherwise the procedure uses non MBMS-service-associated signalling.

8.4.2 Successful Operation

Figure 8.4.2-1. Error Indication procedure, MME originated. Successful operation.

Figure 8.4.2.1-2. Error Indication procedure, MCE originated. Successful operation.

When the conditions defined in clause 10 are fulfilled, the Error Indication procedure is initiated by an ERROR INDICATION message sent from the receiving node.

The ERROR INDICATION message shall contain at least either the Cause IE or the Criticality Diagnostics IE.

In case the Error Indication procedure is triggered by utilising MBMS-service-associated signalling the MCE MBMS M3AP ID IE and the MME MBMS M3AP IE shall be included in the ERROR INDICATION message. If one or both of MCE MBMS M3AP ID IE and the MME MBMS M3AP IE are not correct, the cause shall be set to appropriate value e.g. "Unknown or already allocated MCE MBMS M3AP ID", "Unknown or already allocated MME MBMS M3AP ID" or "Unknown or inconsistent pair of MBMS M3AP ID".

8.4.3 Abnormal Conditions

8.5 Reset

8.5.1 General

The purpose of the Reset procedure is to initialise or re-initialise the E-UTRAN, or part of E-UTRAN M3AP MBMS-related contexts, in the event of a failure in the EPC or vice versa. This procedure does not affect the application level configuration data exchanged during, e.g. the M3 Setup procedure.

The procedure uses non MBMS-service associated signalling.

8.5.2 Successful Operation

8.5.2.1 Reset Procedure Initiated from the MME

Figure 8.5.2.1-1: Reset procedure initiated from the MME. Successful operation.

In the event of a failure at the MME, which has resulted in the loss of some or all transaction reference information, a RESET message shall be sent to the MCE.

At reception of RESET message the MCE shall release all allocated resources on M3 related to MBMS-service association(s) indicated explicitly or implicitly in the RESET message and remove the MBMS-service contexts including MBMS M3AP IDs for the indicated MBMS service associations.

After the MCE has released all assigned M3 resources and the MBMS M3AP IDs for all indicated MBMS service associations which can be used for new MBMS-service-associated logical M3-connections over the M3 interface, the MCE shall respond with the RESET ACKNOWLEDGE message.

If the RESET message contains the MBMS-Service-associated logical M3-connection list IE, then:

– The MCE shall use the MME MBMS M3AP ID IE and/or the MCE MBMS M3AP ID IE to explicitly identify the MBMS service association(s) to be reset.

– The MCE shall in the RESET ACKNOWLEDGE message include, for each MBMS service association to be reset, the MBMS-Service-associated logical M3-connection Item IE in the MBMS-Service-associated logical M3-connection list IE. The MBMS-Service -associated logical M3-connection Item IEs shall be in the same order as received in the RESET message and shall include also unknown MBMS-Service-associated logical M3-connections. Empty MBMS-Service-associated logical M3-connection Item IEs, received in the RESET message, may be omitted in the RESET ACKNOWLEDGE message.

– If the MME MBMS M3AP ID IE is included in the MBMS-Service-associated logical M3-connection Item IE for an MBMS service association, the MCE shall include the MME MBMS M3AP ID IE in the corresponding MBMS-Service-associated logical M3-connection Item IE in the RESET ACKNOWLEDGE message.

– If the MCE MBMS M3AP ID IE is included in an MBMS-Service-associated logical M3-connection Item IE for an MBMS service association, the MCE shall include the MCE MBMS M3AP ID IE in the corresponding MBMS-Service-associated logical M3-connection Item IE in the RESET ACKNOWLEDGE message.

Interactions with other procedures:

If the RESET message is received, any other ongoing procedure (except another Reset procedure) on the same M3 interface related to an MBMS service association, indicated explicitly or implicitly in the RESET message, shall be aborted.

8.5.2.2 Reset Procedure Initiated from the E-UTRAN

Figure 8.5.2.2-1: Reset procedure initiated from the E-UTRAN. Successful operation.

In the event of a failure at the MCE, which has resulted in the loss of some or all transaction reference information, a RESET message shall be sent to the MME.

At reception of RESET message the MME shall release all allocated resources on M3 related to the MBMS service association(s) indicated explicitly or implicitly in the RESET message and remove the MBMS M3AP ID for the indicated MBMS service associations.

After the MME has released all assigned M3 resources and the MBMS M3AP IDs for all indicated MBMS service associations which can be used for new MBMS-service-associated logical M3-connections over the M3 interface, the MME shall respond with the RESET ACKNOWLEDGE message.

If the RESET message contains the MBMS-Service-associated logical M3-connection list IE, then:

– The MME shall use the MME MBMS M3AP ID IE and/or the MCE MBMS M3AP ID IE to explicitly identify the MBMS service association(s) to be reset.

– The MME shall in the RESET ACKNOWLEDGE message include, for each MBMS service association to be reset, the MBMS-Service-associated logical M3-connection Item IE in the MBMS-Service-associated logical M3-connection list IE. The MBMS-Service -associated logical M3-connection Item IEs shall be in the same order as received in the RESET message and shall include also unknown MBMS-Service-associated logical M3-connections. Empty MBMS-Service-associated logical M3-connection Item IEs, received in the RESET message, may be omitted in the RESET ACKNOWLEDGE message.

– If the MME MBMS M3AP ID IE is included in the MBMS-Service-associated logical M3-connection Item IE for an MBMS service association, the MME shall include the MME MBMS M3AP ID IE in the corresponding MBMS-Service-associated logical M3-connection Item IE in the RESET ACKNOWLEDGE message.

– If the MCE MBMS M3AP ID IE is included in an MBMS-Service-associated logical M3-connection Item IE for an MBMS service association, the MME shall include the MCE MBMS M3AP ID IE in the corresponding MBMS-Service-associated logical M3-connection Item IE in the RESET ACKNOWLEDGE message.

Interactions with other procedures:

If the RESET message is received, any other ongoing procedure (except another Reset procedure) on the same M3 interface related to an MBMS service association, indicated explicitly or implicitly in the RESET message, shall be aborted.

8.5.3 Abnormal Conditions

8.5.3.1 Abnormal Condition at the EPC

If the RESET message includes the MBMS-Service-associated logical M3-connection list IE, but neither the MME MBMS M3AP ID IE nor the MCE MBMS M3AP ID IE is present for an MBMS-Service-associated logical M3-connection Item IE, then the MME shall ignore the MBMS-Service-associated logical M3-connection Item IE. The MME may return the empty MBMS-Service-associated logical M3-connection Item IE in the MBMS-Service-associated logical M3-connection list IE in the RESET ACKNOWLEDGE message.

8.5.3.2 Abnormal Condition at the E-UTRAN

If the RESET message includes the MBMS-Service-associated logical M3-connection list IE, but neither the MME MBMS M3AP ID IE nor the MCE MBMS M3AP ID IE is present for an MBMS-Service-associated logical M3-connection Item IE, then the MCE shall ignore the MBMS-Service-associated logical M3-connection Item IE. The MCE may return the empty MBMS-Service-associated logical M3-connection Item IE in the MBMS-Service-associated logical M3-connection list IE in the RESET ACKNOWLEDGE message.

8.5.3.3 Crossing of Reset Messages

If Reset procedure is ongoing in MCE and the MCE receives a RESET message from the peer entity on the same M3 interface related to one or several MBMS service associations previously requested to be reset, indicated explicitly or implicitly in the received RESET message, the MCE shall respond with RESET ACKNOWLEDGE message as described in 8.5.2.1.

If Reset procedure is ongoing in MME and the MME receives a RESET message from the peer entity on the same M3 interface related to one or several MBMS service associations previously requested to be reset, indicated explicitly or implicitly in the received RESET message, the MME shall respond with RESET ACKNOWLEDGE message as described in 8.5.2.2.

8.6 MBMS Session Update

8.6.1 General

The purpose of the MBMS Session Update procedure is to inform the MCE about changing characteristics of the MBMS session.

The procedure uses MBMS-Service-associated signalling.

8.6.2 Successful Operation

Figure 8.6.2-1. MBMS Session Update procedure. Successful operation.

The MME initiates the procedure by sending an MBMS SESSION UPDATE REQUEST message to the MCE.

The MCE shall use the information contained in the MBMS SESSION UPDATE REQUEST message to update its own parameters of this session such as the service area parameters, or the list of cell identities, or the allocation and retention priority (ARP) of the session. In MBSFN operation, if the ARP parameter is updated, the corresponding update of resources shall follow the principles described for the MBMS Session Start procedure. The MCE shall then, if needed, transfer the updated parameters to the involved eNBs according to the service area, or the list of cell identities.

In MBSFN operation, if the Time of MBMS Data Transfer IE is included in the MBMS SESSION UPDATE REQUEST message, the MCE shall, if supported, take it into account for the synchronization of the corresponding MCCH Update instead of the Minimum Time to MBMS Data Transfer IE. The MCE shall ensure the eNB applies the MCCH update from the last modification period before the time indicated by the Time of MBMS Data Transfer IE. The MCE shall ignore the information contained in the received Minimum Time to MBMS Data Transfer IE.

After receiving the response from the involved eNBs the MCE shall report to the MME in the MBMS SESSION UPDATE RESPONSE message the result of the update.

8.6.3 Unsuccessful Operation

Figure 8.6.3-1: MBMS Session Update procedure. Unsuccessful operation.

If the MCE determines that the E-UTRAN is not able to accommodate the requested updating, the MCE shall send to the MME the MBMS SESSION UPDATE FAILURE message.

8.6.4 Abnormal Conditions

Not applicable.

8.7 M3 Setup

8.7.1 General

The purpose of the M3 Setup procedure is to exchange application level data needed for the MCE and MME to correctly interoperate on the M3 interface. The procedure uses non MBMS-service associated signalling.

This procedure erases any existing application level data in the MCE and the MME and replaces it by the one received. This procedure also re-initialises the E-UTRAN M3AP service-related contexts (if any) and erases all related MBMS-service-associated logical M3 connections in the two nodes like a Reset procedure would do.

8.7.2 Successful Operation

Figure 8.7.2-1: M3 Setup procedure- Successful operation.

The MCE initiates the procedure by sending a M3 SETUP REQUEST message including the appropriate data to the MME. The MME responds with a M3 SETUP RESPONSE.

The exchanged data shall be stored in respective node and used for the duration of the TNL association.

If the M3 SETUP REQUEST message contains the MCE Name IE the MME may use this IE as a human readable name of the MCE.

8.7.3 Unsuccessful Operation

Figure 8.7.3-1: M3 Setup procedure. Unsuccessful operation.

If the MME cannot accept the setup, it should respond with a M3 SETUP FAILURE and appropriate cause value.

If the M3 SETUP FAILURE message includes the Time To Wait IE the MCE shall wait at least for the indicated time before reinitiating the M3 setup towards the same MME.

8.7.4 Abnormal Conditions

Void

8.8 MCE Configuration Update

8.8.1 General

The purpose of the MCE Configuration Update procedure is to update application level configuration data needed for the MCE and MME to interoperate correctly on the M3 interface.

The procedure uses non MBMS-service-associated signalling.

8.8.2 Successful Operation

Figure 8.8.2-1: MCE Configuration Update procedure. Successful operation.

The MCE initiates the procedure by sending an MCE CONFIGURATION UPDATE message to the MME including an appropriate set of updated configuration data that it has just taken into operational use. The MME responds with MCE CONFIGURATION UPDATE ACKNOWLEDGE message to acknowledge that it successfully updated the configuration data. If information element(s) is/are not included in the MCE CONFIGURATION UPDATE message, the MME shall interpret that the corresponding configuration data is/are not changed and shall continue to operate the M3 with the existing related configuration data.

If the served MBMS Service Areas are to be updated, the complete set of supported MBMS Service Area Identities shall be included in the MBMS Service Area List IE.

If the MCE CONFIGURATION UPDATE message contains the MCE Name IE, the MME may use this IE as a human readable name of the MCE.

The updated configuration data shall be stored in both the MCE and the MME and used for the duration of the TNL association or until any further update is triggered by the MCE.

The MCE may initiate a further MCE Configuration Update procedure only after a previous MCE Configuration Update procedure has been completed.

8.8.3 Unsuccessful Operation

Figure 8.8.3-1: MCE Configuration Update procedure. Unsuccessful operation.

If the MME cannot accept the update, it shall respond with an MCE CONFIGURATION UPDATE FAILURE message and appropriate cause value.

If the MCE CONFIGURATION UPDATE FAILURE message includes the Time To Wait IE, the MCE shall wait at least for the indicated time before reinitiating the MCE Configuration Update procedure towards the MME. Both nodes shall continue to operate the M3 interface with their respective configuration data.

8.8.4 Abnormal Conditions

If the MCE after initiating the MCE Configuration Update procedure receives neither an MCE CONFIGURATION UPDATE ACKNOWLEDGE nor an MCE CONFIGURATION UPDATE FAILURE message, the MCE may reinitiate a further MCE Configuration Update procedure towards the same MME, provided that the content of the new MCE CONFIGURATION UPDATE message is identical to the content of the previously unacknowledged MCE CONFIGURATION UPDATE message.