Section: 5.6.1.4.2 UE is using EPS services with control plane CIoT EPS optimization
Content: For case a in clause 5.6.1.1, upon receipt of the CONTROL PLANE SERVICE REQUEST message with Control plane service type indicating "mobile terminating request", after completion of the EMM common procedures according to clause 5.6.1.3: 1) if the MME needs to perform an EPS bearer context status synchronization - for an EPS bearer context associated with Control plane only indication; or - for an EPS bearer context not associated with Control plane only indication, there is no downlink user data pending to be delivered via the user plane, and the UE did not set the "active" flag in the Control plane service type IE to 1; 2) if the control plane data back-off time for the UE is stored in MME and the MME decides to deactivate congestion control for transport of user data via the control plane, or 3) if the MME needs to provide the UE with Forbidden TAI(s) for the list of "forbidden tracking areas for roaming" IE or Forbidden TAI(s) for the list of "forbidden tracking areas for regional provision of service" IE, then the MME shall send a SERVICE ACCEPT message. Furthermore the MME may: 1) initiate the transport of user data via the control plane procedure or any other NAS signalling procedure; 2) if supported by the UE and required by the network, initiate the setup of the user plane radio bearer(s); or 3) send a NAS signalling message not related to an EMM common procedure to the UE if downlink signalling is pending. For case b in clause 5.6.1.1, upon receipt of the CONTROL PLANE SERVICE REQUEST message with Control plane service type indicating "mobile originating request", after completion of the EMM common procedures according to clause 5.6.1.3, if any, if the MME needs to provide the UE with Forbidden TAI(s) for the list of "forbidden tracking areas for roaming" IE or Forbidden TAI(s) for the list of "forbidden tracking areas for regional provision of service" IE or to perform an EPS bearer context status synchronization - for an EPS bearer context associated with Control plane only indication; or - for an EPS bearer context not associated with Control plane only indication, there is no downlink user data pending to be delivered via the user plane, and the UE did not set the "active" flag in the Control plane service type IE to 1, then the MME shall send a SERVICE ACCEPT message. Furthermore, the MME may: 1) initiate release of the NAS signalling connection upon receipt of an indication from the ESM layer (see clause 6.6.4.2), unless the MME has additional downlink user data or signalling pending; 2) initiate the setup of the user plane radio bearer(s), if downlink user data is pending to be delivered via the user plane or the UE has set the "active" flag in the Control plane service type IE to 1; 3) send an ESM DATA TRANSPORT message to the UE, if downlink user data is pending to be delivered via the control plane; 4) send a NAS signalling message not related to an EMM common procedure to the UE if downlink signalling is pending; or 5) send a SERVICE ACCEPT message to complete the service request procedure, if no NAS security mode control procedure was initiated, the MME did not send a SERVICE ACCEPT message as specified above to perform an EPS bearer context status synchronization, and the MME did not initiate any of the procedures specified in item 1 to 4 above. NOTE 1: The MME can initiate the setup of the user plane radio bearer(s) if the MME decides to activate the congestion control for transport of user data via the control plane. For case m in clause 5.6.1.1, upon receipt of the CONTROL PLANE SERVICE REQUEST message with Control plane service type indicating "mobile originating request" and the "active" flag in the Control plane service type IE set to 1: 1) if the MME accepts the request, the MME shall initiate the setup of the user plane radio bearer(s) for all active EPS bearer contexts of SGi PDN connections that are established without control plane only indication. 2) if the MME does not accept the request, the MME shall send a SERVICE ACCEPT message to complete the service request procedure. NOTE 2: The MME takes into account the maximum number of user plane radio bearers supported by the UE, in addition to local policies and the UE's preferred CIoT network behaviour when deciding whether to accept the request to establish user plane bearer(s) as described in clause 5.3.15. If the MME accepts the request, all SGi PDN connections are considered as established without Control plane only indication. NOTE 3: In this release of the specification, a UE in NB-S1 mode can support a maximum of 2 user plane radio bearers (see clause 6.5.0). For case c in clause 5.6.1.1, upon receipt of the CONTROL PLANE SERVICE REQUEST message with Control plane service type indicating "mobile originating request" and without an ESM message container IE, after completion of the EMM common procedures according to clause 5.6.1.3, if any, the MME proceeds as follows: If the MME needs to perform an EPS bearer context status synchronization - for an EPS bearer context associated with Control plane only indication; or - for an EPS bearer context not associated with Control plane only indication, and there is no downlink user data pending to be delivered via the user plane, then the MME shall send a SERVICE ACCEPT message. Furthermore, the MME may: 1) initiate the setup of the user plane radio bearer(s), if downlink user data is pending to be delivered via the user plane; 2) send an ESM DATA TRANSPORT message to the UE, if downlink user data is pending to be delivered via the control plane; 3) send a NAS signalling message not related to an EMM common procedure to the UE, if downlink signalling is pending; or 4) send a SERVICE ACCEPT message to complete the service request procedure, if no NAS security mode control procedure was initiated, the MME did not send a SERVICE ACCEPT message as specified above to perform an EPS bearer context status synchronization, and the MME did not initiate any of the procedures specified in item 1 to 3 above. If the MUSIM UE does not include the Paging restriction IE in the CONTROL PLANE SERVICE REQUEST message, the MME shall delete any stored paging restriction for the UE and stop restricting paging. For cases p and q in clause 5.6.1.1 when the MUSIM UE sets the Request type to "NAS signalling connection release" or to "Rejection of paging" in the UE request type IE in the CONTROL PLANE SERVICE REQUEST message and if the UE requests restriction of paging by including the Paging restriction IE, the MME: - if accepts the paging restriction, shall include the EPS additional request result IE in the SERVICE ACCEPT message and set the Paging restriction decision to "paging restriction is accepted". The MME shall store the paging restriction of the UE, enforce these restrictions in the paging procedure as described in clause 5.6.2; or - if rejects the paging restriction, shall include the EPS additional request result IE in the SERVICE ACCEPT message and set the Paging restriction decision to "paging restriction is rejected", and shall discard the received paging restriction. The MME shall delete any stored paging restriction for the UE and stop restricting paging; and - shall initiate the release of the NAS signalling connection after the completion of the service request procedure. In NB-S1 mode, for cases a, b, c and m in clause 5.6.1.1, if the MME needs to initiate the setup of user plane radio bearer(s), the MME shall check if the UE can support the establishment of additional user plane radio bearer based on the multiple DRB support indicated by UE in the UE network capability IE. For cases a, b and c in clause 5.6.1.1, if the EPS bearer context status IE is included in the CONTROL PLANE SERVICE REQUEST message, the network shall deactivate all those EPS bearer contexts locally (without peer-to-peer signalling between the network and the UE) which are active on the network side but are indicated by the UE as being inactive. If a default EPS bearer context is marked as inactive in the EPS bearer context status IE included in the CONTROL PLANE SERVICE REQUEST message, and this default bearer is not associated with the last PDN connection of the UE in the MME, the MME shall locally deactivate all EPS bearer contexts associated to the PDN connection with the default EPS bearer context without peer-to-peer ESM signalling to the UE. If the default bearer is associated with the last remaining PDN connection of the UE in the MME, and EMM-REGISTERED without PDN connection is supported by the UE and the MME, the MME shall locally deactivate all EPS bearer contexts associated to the PDN connection with the default EPS bearer context without peer-to-peer ESM signalling to the UE. If the EPS bearer context status IE is included in the CONTROL PLANE SERVICE REQUEST and the MME decides to respond with a SERVICE ACCEPT message, the MME shall include an EPS bearer context status IE, indicating which EPS bearer contexts are active in the MME, except for the case when no EPS bearer context exists on the network side. If the MME needs to initiate an EPS bearer context status synchronization, the MME may include an EPS bearer context status IE in the SERVICE ACCEPT message also if no EPS bearer context status IE was included in the CONTROL PLANE SERVICE REQUEST message. If the MME sends a SERVICE ACCEPT message upon receipt of the CONTROL PLANE SERVICE REQUEST message piggybacked with the ESM DATA TRANSPORT message: - if the Release assistance indication IE is set to "No further uplink and no further downlink data transmission subsequent to the uplink data transmission is expected" in the message; - if the UE has indicated support for the control plane data back-off timer; and - if the MME decides to activate the congestion control for transport of user data via the control plane, then the MME shall include the T3448 value IE in the SERVICE ACCEPT message. If the MME sends a SERVICE ACCEPT message and decides to deactivate congestion control for transport of user data via the control plane then the MME shall delete the stored control plane data back-off time for the UE and the MME shall not include timer T3448 value IE in SERVICE ACCEPT message. For cases a, b, c and m in clause 5.6.1.1, if the EPS bearer context status IE is included in the CONTROL PLANE SERVICE REQUEST message or the MME needs to initiate an EPS bearer context status synchronization, the MME shall consider the service request procedure successfully completed when it sends the SERVICE ACCEPT message. If the EPS bearer context status IE is not included in the CONTROL PLANE SERVICE REQUEST message and the MME does not need to initiate an EPS bearer context status synchronization, the MME shall consider the service request procedure successfully completed in the following cases: - when it successfully completes a NAS security mode control procedure; - when it receives an indication from the lower layer that the user plane is setup, if radio bearer establishment is required; - upon receipt of the CONTROL PLANE SERVICE REQUEST message and completion of the EMM common procedures, if any, if the CONTROL PLANE SERVICE REQUEST message was successfully integrity checked and the ESM message container or NAS message container in the CONTROL PLANE SERVICE REQUEST message, if applicable, was successfully deciphered, radio bearer establishment is not required, and the MME has downlink user data or signalling not related to an EMM common procedure pending; and - with the transmission of a SERVICE ACCEPT message or with the decision to initiate release of the NAS signalling connection, if the CONTROL PLANE SERVICE REQUEST message was successfully integrity checked and the ESM message container or NAS message container in the CONTROL PLANE SERVICE REQUEST message, if applicable, was successfully deciphered, radio bearer establishment is not required, and the MME does not have any downlink user data or signalling pending. If the MME considers the service request procedure successfully completed the MME shall: 1) forward the contents of the ESM message container IE, if any, to the ESM layer; and 2) forward the contents of the NAS message container IE, if any. For cases a, b and c in clause 5.6.1.1, the UE shall treat the receipt of any of the following as successful completion of the procedure: - a SECURITY MODE COMMAND message; - a security protected EMM message different from a SERVICE REJECT message and not related to an EMM common procedure; - a security protected ESM message; and - receipt of the indication from the lower layers that the user plane radio bearers are set up. Upon successful completion of the procedure, the UE shall reset the service request attempt counter, stop the timer T3417 and enter the state EMM-REGISTERED. If the CONTROL PLANE SERVICE REQUEST message was sent with the "active" flag in the Control plane service type IE set to "Radio bearer establishment requested", the UE shall locally deactivate the EPS bearer contexts that do not have a user plane radio bearer established upon successful completion of the service request procedure, except for the case when the MUSIM UE in the CONTROL SERVICE REQUEST message sets the Request type to "NAS signalling connection release" or to "Rejection of paging" in the UE request type IE. NOTE 4: The security protected EMM message can be e.g. a SERVICE ACCEPT message and the ESM message an ESM DATA TRANSPORT message. For case m in clause 5.6.1.1, the UE shall treat the indication from the lower layers that the user plane radio bearers are set up as successful completion of the procedure. The UE shall treat the receipt of a SERVICE ACCEPT message as completion of the procedure without the establishment of the user plane radio bearers. For both cases, the UE shall reset the service request attempt counter, stop the timer T3417 and enter the state EMM-REGISTERED. For case b in clause 5.6.1.1, the UE shall also treat the indication from the lower layers that the RRC connection has been released as successful completion of the procedure. The UE shall reset the service request attempt counter, stop the timer T3417 and enter the state EMM-REGISTERED. For cases a, c and m in clause 5.6.1.1, the UE shall treat the indication from the lower layers that the RRC connection has been released as an abnormal case and shall follow the procedure described in clause 5.6.1.6, item b. For cases p and q in clause 5.6.1.1, when the MUSIM UE in the CONTROL PLANE SERVICE REQUEST message sets the Request type to "NAS signalling connection release" or to "Rejection of paging" in the UE request type IE, the UE shall treat the receipt of SERVICE ACCEPT message as the successful completion of the procedure and the UE shall reset the service request attempt counter, stop timer T3417, enter the state EMM-REGISTERED and not deactivate EPS bearer contexts locally. For case o in clause 5.6.1.1, the UE shall treat the receipt of SERVICE ACCEPT message as the successful completion of the procedure. The UE shall reset the service request attempt counter, stop timer T3417 and enter the state EMM-REGISTERED. For cases a, b and c in clause 5.6.1.1, - if the MME needs to initiate an EPS bearer context status synchronization or to provide the UE with Forbidden TAI(s) for the list of "forbidden tracking areas for roaming" IE or Forbidden TAI(s) for the list of "forbidden tracking areas for regional provision of service", the UE can receive a SERVICE ACCEPT message even after it received a SECURITY MODE COMMAND message or an indication from the lower layers that the user plane radio bearers are set up and determined successful completion of the service request procedure. Upon receipt of the SECURITY MODE COMMAND message or an indication from the lower layers that the user plane radio bearers are set up, the UE shall start timer T3449. If the UE receives a security protected ESM message or a security protected EMM message not related to an EMM common procedure, the UE shall stop the timer T3449. If the UE receives a SERVICE ACCEPT message while the timer T3449 is running, the UE shall treat the SERVICE ACCEPT message and stop the timer T3449. If the UE is not in state EMM-SERVICE-REQUEST-INITIATED and timer T3449 is not running, the receipt of the SERVICE ACCEPT message is considered as protocol error and the UE shall return EMM STATUS message as specified in clause 7.4; otherwise the UE shall treat the SERVICE ACCEPT message; and - if the UE treats the SERVICE ACCEPT message and an EPS bearer context status IE is included in the message, the UE shall deactivate all those EPS bearers contexts locally (without peer-to-peer signalling between the UE and the MME) which are active in the UE, but are indicated by the MME as being inactive. If a default EPS bearer context is marked as inactive in the EPS bearer context status IE included in the SERVICE ACCEPT message, and this default bearer is not associated with the last remaining PDN connection in the UE, the UE shall locally deactivate all EPS bearer contexts associated to the PDN connection with the default EPS bearer context without peer-to-peer ESM signalling to the MME. If the default bearer is associated with the last remaining PDN connection of the UE in the MME, and EMM-REGISTERED without PDN connection is supported by the UE and the MME, the UE shall locally deactivate all EPS bearer contexts associated to the PDN connection with the default EPS bearer context without peer-to-peer ESM signalling to the MME. If the T3448 value IE is present in the received SERVICE ACCEPT message, the UE shall: - stop timer T3448 if it is running; - consider the transport of user data via the control plane as successful; and - start timer T3448 with the value provided in the T3448 value IE. If the UE is using EPS services with control plane CIoT EPS optimization, the T3448 value IE is present in the SERVICE ACCEPT message and the value indicates that this timer is either zero or deactivated, the UE shall consider this case as an abnormal case and proceed as if the T3448 value IE is not present. If the UE in EMM-IDLE mode initiated the service request procedure by sending a CONTROL PLANE SERVICE REQUEST message and the SERVICE ACCEPT message does not include the T3448 value IE and if timer T3448 is running, then the UE shall stop timer T3448. If the MME received the list of TAIs from the satellite E-UTRAN as described in 3GPP TS 23.401[ General Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access ]  [10], and determines that, by UE subscription and operator's preference, any but not all TAIs in the received list of TAIs is forbidden for roaming or for regional provision of service, the MME shall include the TAI(s) in: a) the Forbidden TAI(s) for the list of "forbidden tracking areas for roaming" IE; b) the Forbidden TAI(s) for the list of "forbidden tracking areas for regional provision of service" IE; or c) both, in the SERVICE ACCEPT message. NOTE 5: "Forbidden tracking areas for roaming" corresponds to cause values #13 and #15, and "forbidden tracking areas for regional provision of service" corresponds cause value #12. If the UE receives the Forbidden TAI(s) for the list of "forbidden tracking areas for roaming" IE in the SERVICE ACCEPT message and the TAI(s) included in the IE which are belonging to the serving PLMN or equivalent PLMN(s) is not part of the list of "forbidden tracking areas for roaming", the UE shall store the TAI(s) included in the IE into the list of "forbidden tracking areas for roaming" and ignore the TAI(s) which do not belong to the serving PLMN or equivalent PLMN(s). If the UE receives the Forbidden TAI(s) for the list of "forbidden tracking areas for regional provision of service" IE in the SERVICE ACCEPT message and the TAI(s) included in the IE which are belonging to the serving PLMN or equivalent PLMN(s) is not part of the list of "forbidden tracking areas for regional provision of service", the UE shall store the TAI(s) included in the IE into the list of "forbidden tracking areas for regional provision of service" and ignore the TAI(s) which do not belong to the serving PLMN or equivalent PLMN(s).