Content for  TS 38.413  Word version:  18.0.0

The purpose of the PDU Session Resource Setup procedure is to assign resources on Uu and NG-U for one or several PDU sessions and the corresponding QoS flows, and to setup corresponding DRBs for a given UE. The procedure uses UE-associated signalling.

The AMF initiates the procedure by sending a PDU SESSION RESOURCE SETUP REQUEST message to the NG-RAN node. The PDU SESSION RESOURCE SETUP REQUEST message shall contain the information required by the NG-RAN node to setup the PDU session related NG-RAN configuration consisting of at least one PDU session resource and include each PDU session resource to setup in the PDU Session Resource Setup Request List IE. Upon reception of the PDU SESSION RESOURCE SETUP REQUEST message, if resources are available for the requested configuration, the NG-RAN node shall execute the requested NG-RAN configuration and allocate associated resources over NG and over Uu for each PDU session listed in the PDU Session Resource Setup Request List IE. If the RAN Paging Priority IE is included in the PDU SESSION RESOURCE SETUP REQUEST message, the NG-RAN node may use it to determine a priority for paging the UE in RRC_INACTIVE state. For each requested PDU session, if resources are available for the requested configuration, the NG-RAN node shall establish at least one DRB and associate each accepted QoS flow of the PDU session which is not associated with an MBS QoS flow to a DRB established. For each PDU session successfully established the NG-RAN node shall pass to the UE the PDU Session NAS-PDU IE, if included. The NG-RAN node shall not send to the UE the PDU Session NAS PDUs associated to the failed PDU sessions. If the NAS-PDU IE is included in the PDU SESSION RESOURCE SETUP REQUEST message, the NG-RAN node shall pass it to the UE. For each PDU session the NG-RAN node shall store the UL NG-U UP TNL Information IE included in the PDU Session Resource Setup Request Transfer IE contained in the PDU SESSION RESOURCE SETUP REQUEST message and use it as the uplink termination point for the user plane data for this PDU session. For each PDU session, if the Additional UL NG-U UP TNL Information IE is included in the PDU Session Resource Setup Request Transfer IE contained in the PDU SESSION RESOURCE SETUP REQUEST message, the NG-RAN node may allocate for this split PDU session resources for an additional NG-U transport bearer for some or all of the QoS flows present in the QoS Flow Setup Request List IE and it shall indicate these QoS flows in the Additional DL QoS Flow per TNL Information IE in the PDU Session Resource Setup Response Transfer IE. In case the Additional DL QoS Flow per TNL Information IE is not included the SMF shall consider the proposed additional UL NG-U UP TNL information as available again. For each PDU session, if the Network Instance IE is included in the PDU Session Resource Setup Request Transfer IE contained in the PDU SESSION RESOURCE SETUP REQUEST message and the Common Network Instance IE is not present, the NG-RAN node shall, if supported, use it when selecting transport network resource as specified in TS 23.501. For each PDU session, if the Common Network Instance IE is included in the PDU Session Resource Setup Request Transfer IE or in the Additional UL NG-U UP TNL Information IE, or in the Additional Redundant UL NG-U UP TNL Information IE contained in the PDU SESSION RESOURCE SETUP REQUEST message, the NG-RAN node shall, if supported, use it when selecting transport network resource for the concerned NG-U transport bearer as specified in TS 23.501. For each PDU session, if the Redundant UL NG-U UP TNL Information IE is included in the PDU Session Resource Setup Request Transfer IE of the PDU SESSION RESOURCE SETUP REQUEST message, the NG-RAN node shall, if supported, use it as the uplink termination point for the user plane data for this PDU session for the redundant transmission and it shall include the Redundant QoS Flow per TNL Information IE in the PDU Session Resource Setup Response Transfer IE as described in TS 23.501. For each PDU session, if the Additional Redundant UL NG-U UP TNL Information IE is included in the PDU Session Resource Setup Request Transfer IE contained in the PDU SESSION RESOURCE SETUP REQUEST message, the NG-RAN node may allocate for this split PDU session resources for an additional redundant NG-U transport bearer for some or all of the QoS flows present in the QoS Flow Setup Request List IE and it shall indicate these QoS flows in the Additional Redundant DL QoS Flow per TNL Information IE in the PDU Session Resource Setup Response Transfer IE. In case the Additional Redundant DL QoS Flow per TNL Information IE is not included the SMF shall consider the proposed additional Redundant UL NG-U UP TNL information as available again. For each PDU session, if the Redundant Common Network Instance IE is included in the PDU Session Resource Setup Request Transfer IE contained in the PDU SESSION RESOURCE SETUP REQUEST message, the NG-RAN node shall, if supported, use it when selecting transport network resource for the redundant transmission as specified in TS 23.501. For each PDU session, if the TSC Traffic Characteristics IE is included in the PDU Session Resource Setup Request Transfer IE contained in the PDU SESSION RESOURCE SETUP REQUEST message, the NG-RAN node shall, if supported, store it and use it as specified in TS 23.501. For each QoS flow which has been successfully established, if the Burst Arrival Time IE is included in the TSC Assistance Information Uplink IE of the TSC Traffic Characteristics IE, the NG-RAN node may include the AN Packet Delay Budget Uplink IE for the same QoS flow within the PDU SESSION RESOURCE SETUP RESPONSE message as specified in TS 23.501. If the RAN Feedback Type IE is included in the TSC Traffic Characteristics IE, the NG-RAN node shall, if supported, take this information into account when determining the feedback to provide in the TSC Traffic Characteristics Feedback IE in the PDU Session Resource Setup Response Transfer IE in the PDU SESSION RESOURCE SETUP RESPONSE message as specified in TS 23.501. For each PDU session, if the PDU Session Type IE included in the PDU Session Resource Setup Request Transfer IE of the PDU SESSION RESOURCE SETUP REQUEST message is set to "ethernet", the NG-RAN node may perform appropriate header compression for the concerned PDU session, or if it is set to "unstructured", the NG-RAN node shall not perform header compression for the concerned PDU session. For each PDU session for which the Security Indication IE is included in the PDU Session Resource Setup Request Transfer IE of the PDU SESSION RESOURCE SETUP REQUEST message, and the Integrity Protection Indication IE or Confidentiality Protection Indication IE is set to "required", then the NG-RAN node shall perform user plane integrity protection or ciphering, respectively, for the concerned PDU session. If the NG-RAN node cannot perform the user plane integrity protection or ciphering, it shall reject the setup of the PDU session resources with an appropriate cause value. If the NG-RAN node is an ng-eNB, it shall behave as specified in TS 33.501. For each PDU session for which the Security Indication IE is included in the PDU Session Resource Setup Request Transfer IE of the PDU SESSION RESOURCE SETUP REQUEST message, and the Integrity Protection Indication IE or Confidentiality Protection Indication IE is set to "preferred", then the NG-RAN node should, if supported, perform user plane integrity protection or ciphering, respectively, for the concerned PDU session and shall notify whether it performed the user plane integrity protection or ciphering by including the Integrity Protection Result IE or Confidentiality Protection Result IE, respectively, in the PDU Session Resource Setup Response Transfer IE of the PDU SESSION RESOURCE SETUP RESPONSE message. For each PDU session for which the Maximum Integrity Protected Data Rate Downlink IE or the Maximum Integrity Protected Data Rate Uplink IE are included in the Security Indication IE in the PDU Session Resource Setup Request Transfer IE of the PDU SESSION RESOURCE SETUP REQUEST message, the NG-RAN node shall store the respective information and, if integrity protection is to be performed for the PDU session, it shall enforce the traffic limits corresponding to the received values, for the concerned PDU session and concerned UE, as specified in TS 23.501. For each PDU session for which the Security Indication IE is included in the PDU Session Resource Setup Request Transfer IE of the PDU SESSION RESOURCE SETUP REQUEST message:

• if the Integrity Protection Indication IE is set to "not needed", then the NG-RAN node shall not perform user plane integrity protection for the concerned PDU session;
• if the Confidentiality Protection Indication IE is set to "not needed", then the NG-RAN node shall not perform user plane ciphering for the concerned PDU session.

For each PDU session for which the PDU Session Aggregate Maximum Bit Rate IE is included in the PDU Session Resource Setup Request Transfer IE of the PDU SESSION RESOURCE SETUP REQUEST message, the NG-RAN node shall store the received value in the UE context and use it when enforcing traffic policing for Non-GBR QoS flows for the concerned UE as specified in TS 23.501. For each PDU session in the PDU SESSION RESOURCE SETUP REQUEST message, if the Additional QoS Flow Information IE is included in the QoS Flow Level QoS Parameters IE in the PDU Session Resource Setup Request Transfer IE of the PDU SESSION RESOURCE SETUP REQUEST message, the NG-RAN node may consider it for the DRB allocation process. It is up to NG-RAN node implementation to decide whether and how to use it. For each PDU session in the PDU SESSION RESOURCE SETUP REQUEST message, if the Alternative QoS Parameters Set List IE is included in the GBR QoS Flow Information IE in the PDU Session Resource Setup Request Transfer IE of the PDU SESSION RESOURCE SETUP REQUEST message, the NG-RAN node may accept the setup of the QoS flow when notification control has been enabled if the requested QoS parameters or at least one of the alternative QoS parameters sets can be fulfilled at the time of setup. In case the NG-RAN node accepts the setup fulfilling one of the alternative QoS parameters it shall indicate the alternative QoS parameters set which it currently fulfils in the Current QoS Parameters Set Index IE within the PDU Session Resource Setup Response Transfer IE of the PDU SESSION RESOURCE SETUP RESPONSE message. For each QoS flow which has been successfully established, the NG-RAN node shall, if supported, store the Redundant QoS Flow Indicator IE if included in the PDU Session Resource Setup Request Transfer IE contained in the PDU SESSION RESOURCE SETUP REQUEST message and consider it for the redundant transmission as specified in TS 23.501. For each QoS flow which has been successfully established, if the QoS Monitoring Request IE was included in the QoS Flow Level QoS Parameters IE contained in the PDU SESSION RESOURCE SETUP REQUEST message, the NG-RAN node shall store this information, and, if supported, perform delay measurement and QoS monitoring, as specified in TS 23.501. If the QoS Monitoring Reporting Frequency IE was included in the QoS Flow Level QoS Parameters IE contained in the PDU SESSION RESOURCE SETUP REQUEST message, the NG-RAN node shall store this information and, if supported, use it for RAN part delay reporting. For each QoS flow requested to be setup, if the PDU Set QoS Parameters IE is included in the QoS Flow Level QoS Parameters IE contained in the PDU SESSION RESOURCE SETUP REQUEST message, the NG-RAN node shall, if supported, store the received PDU Set QoS Parameters in the UE context and use it as specified in TS 23.501. If the ECN Marking or Congestion Information Reporting Request IE is included in the PDU Session Resource Setup Request Transfer IE contained in the PDU SESSION RESOURCE SETUP REQUEST message, the NG-RAN node shall, if supported, use it accordingly for the specific QoS flow. If the ECN Marking or Congestion Information Reporting Status IE is included in the PDU Session Resource Setup Response Transfer IE as described in TS 23.501, the AMF shall, if supported, use it to deduce if ECN marking at NG-RAN or ECN marking at UPF or congestion information reporting is active or not active. For each QoS flow requested to be setup the NG-RAN node shall take into account the received QoS Flow Level QoS Parameters IE. For each QoS flow the NG-RAN node 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 NG-RAN node shall consider the priority level of the requested QoS flow, 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 QoS flow setup has to be performed unconditionally and immediately. If the requested QoS flow is marked as "may trigger pre-emption" and the resource situation requires so, the NG-RAN node may trigger the pre-emption procedure which may then cause the forced release of a lower priority QoS flow which is marked as "pre-emptable". Whilst the process and the extent of the pre-emption procedure are operator-dependent, the pre-emption indicators shall be treated as follows:
  1. The values of the last received Pre-emption Vulnerability IE and Priority Level IE shall prevail.
  2. If the Pre-emption Capability IE is set to "may trigger pre-emption", then this allocation request may trigger the pre-emption procedure.
  3. If the Pre-emption Capability IE is set to "shall not trigger pre-emption", then this allocation request shall not trigger the pre-emption procedure.
  4. If the Pre-emption Vulnerability IE is set to "pre-emptable", then this QoS flow shall be included in the pre-emption process.
  5. If the Pre-emption Vulnerability IE is set to "not pre-emptable", then this QoS flow shall not be included in the pre-emption process.
• The NG-RAN node pre-emption process shall keep the following rules:
  1. The NG-RAN node shall only pre-empt QoS flows with lower priority, in ascending order of priority.
  2. The pre-emption may be done for QoS flows belonging to the same UE or to other UEs.

For each QoS flow which has been successfully established, the NG-RAN node shall store the mapped E-RAB ID if included in the PDU Session Resource Setup Request Transfer IE contained in the PDU SESSION RESOURCE SETUP REQUEST message and use it as specified in TS 38.300. For each PDU session, if the Redundant PDU Session Information IE is included in the PDU Session Resource Setup Request Transfer IE contained in the PDU SESSION RESOURCE SETUP REQUEST message, the NG-RAN node shall, if supported, store the received information in the UE context and setup the redundant user plane for the redundant PDU session as specified in TS 38.300 and TS 23.501. If the PDU Session Type IE is set to "ethernet" and the redundancy requirement is fulfilled using a secondary NG-RAN node, the NG-RAN node shall, if supported, include the Global RAN Node ID of Secondary NG-RAN Node IE in the PDU Session Resource Setup Response Transfer IE of the PDU SESSION RESOURCE SETUP RESPONSE message. If the PDU Session Pair ID IE is included in the Redundant PDU Session Information IE, the NG-RAN node may use it to identify the paired PDU sessions. The NG-RAN node shall report to the AMF in the PDU SESSION RESOURCE SETUP RESPONSE message the result for each PDU session resource requested to be setup:

• For each PDU session resource successfully setup, the PDU Session Resource Setup Response Transfer IE shall be included containing:
  1. The NG-U UP transport layer information to be used for the PDU session and associated list of QoS flows which have been successfully established, in the QoS Flow per TNL Information IE.
  2. The list of QoS flows which failed to be established, if any, in the QoS Flow Failed to Setup List IE. When the NG-RAN node reports unsuccessful establishment of a QoS flow, the cause value should be precise enough to enable the SMF to know the reason for the unsuccessful establishment.
• For each PDU session resource which failed to be setup, the PDU Session Resource Setup Unsuccessful Transfer IE shall be included containing a cause value that should be precise enough to enable the SMF to know the reason for the unsuccessful establishment.

Upon reception of the PDU SESSION RESOURCE SETUP RESPONSE message the AMF shall, for each PDU session indicated in the PDU Session ID IE, transfer transparently the PDU Session Resource Setup Response Transfer IE or PDU Session Resource Setup Unsuccessful Transfer IE to the SMF associated with the concerned PDU session. Upon reception of the PDU SESSION RESOURCE SETUP REQUEST message to setup a QoS flow for IMS voice, if the NG-RAN node is not able to support IMS voice, the NG-RAN node shall initiate EPS fallback or RAT fallback for IMS voice procedure as specified in TS 23.501 and report unsuccessful establishment of the QoS flow in the PDU Session Resource Setup Response Transfer IE or in the PDU Session Resource Setup Unsuccessful Transfer IE with cause value "IMS voice EPS fallback or RAT fallback triggered". For each PDU session for which the Global RAN Node ID of Secondary NG-RAN Node IE is included in the PDU Session Resource Setup Response Transfer IE of the PDU SESSION RESOURCE SETUP RESPONSE message, the SMF shall, if supported, handle this information as specified in TS 23.501. The UE Aggregate Maximum Bit Rate IE should be sent to the NG-RAN node if the AMF has not sent it previously. If it is included in the PDU SESSION RESOURCE SETUP REQUEST message, the NG-RAN node shall store the UE Aggregate Maximum Bit Rate in the UE context, and use the received UE Aggregate Maximum Bit Rate for all Non-GBR QoS flows for the concerned UE as specified in TS 23.501. For each PDU session, if the PDU Session Expected UE Activity Behaviour IE is included in the PDU SESSION RESOURCE SETUP REQUEST message, the NG-RAN node shall, if supported, handle this information as specified in TS 23.501. If the UE Slice Maximum Bit Rate List IE is included in the PDU SESSION RESOURCE SETUP REQUEST message, the NG-RAN node shall, if supported, store the UE Slice Maximum Bit Rate List in the UE context, and use it for each S-NSSAI for the concerned UE as specified in TS 23.501. The NG-RAN node shall, if supported, report in the PDU SESSION RESOURCE SETUP RESPONSE message location information of the UE in the User Location Information IE. If the User Location Information IE is included in the PDU SESSION RESOURCE SETUP RESPONSE message, the AMF shall handle this information as specified in TS 23.501. For each PDU session, if the Downlink TL Container IE is included in the PDU Session Resource Setup Request Transfer IE of the PDU SESSION RESOURCE SETUP REQUEST message, the NG-RAN node shall, if supported, handle it as specified in TS 23.501 and shall include the Uplink TL Container IE in the PDU Session Resource Setup Response Transfer IE as specified in TS 23.501. If the PDU Set QoS Parameters IE is included in the PDU SESSION RESOURCE SETUP REQUEST message, the NG-RAN node shall, if supported, report in the PDU SESSION RESOURCE SETUP RESPONSE message the PDU Set based Handling Indicator IE in the PDU Session Resource Setup Response Transfer IE. If the PDU Set based Handling Indicator IE is included in the PDU Session Resource Setup Response Transfer IE in the PDU SESSION RESOURCE SETUP RESPONSE message, the SMF shall, if supported, handle this information as specified in TS 23.501. Interactions with Handover Preparation procedure:

The unsuccessful operation is specified in the successful operation section.

If the NG-RAN node receives a PDU SESSION RESOURCE SETUP REQUEST message containing several PDU Session ID IEs (in the PDU Session Resource Setup Request List IE) set to the same value, the NG-RAN node shall report the establishment of the corresponding PDU sessions as failed in the PDU SESSION RESOURCE SETUP RESPONSE message with an appropriate cause value. If the NG-RAN node receives a PDU SESSION RESOURCE SETUP REQUEST message containing a PDU Session ID IE (in the PDU Session Resource Setup Request List IE) set to a value that identifies an active PDU session (established before the PDU SESSION RESOURCE SETUP REQUEST message was received), the NG-RAN node shall report the establishment of the new PDU session as failed in the PDU SESSION RESOURCE SETUP RESPONSE message with an appropriate cause value. If the NG-RAN node receives a PDU SESSION RESOURCE SETUP REQUEST message containing a QoS Flow Setup Request List IE in the PDU Session Resource Setup Request Transfer IE including at least one Non-GBR QoS flow but the PDU Session Aggregate Maximum Bit Rate IE is not present, the NG-RAN node shall report the establishment of the corresponding PDU session as failed in the PDU SESSION RESOURCE SETUP REQUEST message with an appropriate cause value. If the NG-RAN node receives a PDU SESSION RESOURCE SETUP REQUEST message containing a QoS Flow Level QoS Parameters IE in the PDU Session Resource Setup Request Transfer IE for a GBR QoS flow but the GBR QoS Flow Information IE is not present, the NG-RAN node shall report the establishment of the corresponding QoS flow as failed in the PDU Session Resource Setup Response Transfer IE of the PDU SESSION RESOURCE SETUP RESPONSE message with an appropriate cause value.If the NG-RAN node receives a PDU SESSION RESOURCE SETUP REQUEST message containing the Delay Critical IE in the Dynamic 5QI Descriptor IE of the QoS Flow Level QoS Parameters IE of the PDU Session Resource Setup Request Transfer IE set to the value "delay critical" but the Maximum Data Burst Volume IE is not present, the NG-RAN node shall report the establishment of the corresponding QoS flow as failed in the PDU Session Resource Setup Response Transfer IE of the PDU SESSION RESOURCE SETUP RESPONSE message with an appropriate cause value.

The purpose of the PDU Session Resource Release procedure is to enable the release of already established PDU session resources for a given UE. The procedure uses UE-associated signalling.

The AMF initiates the procedure by sending a PDU SESSION RESOURCE RELEASE COMMAND message. The PDU SESSION RESOURCE RELEASE COMMAND message shall contain the information required by the NG-RAN node to release at least one PDU session resource, and include each PDU session resource to release in the PDU Session Resource to Release List IE. If a NAS-PDU IE is contained in the PDU SESSION RESOURCE RELEASE COMMAND message, the NG-RAN node shall pass it to the UE. Upon reception of the PDU SESSION RESOURCE RELEASE COMMAND message the NG-RAN node shall execute the release of the requested PDU sessions. For each PDU session to be released the NG-RAN node shall release the corresponding resources over Uu and over NG, if any. If the RAN Paging Priority IE is included in the PDU SESSION RESOURCE RELEASE COMMAND message, the NG-RAN node may use it to determine a priority for paging the UE in RRC_INACTIVE state. The NG-RAN node shall, if supported, report in the PDU SESSION RESOURCE RELEASE RESPONSE message location information of the UE in the User Location Information IE. After sending a PDU SESSION RESOURCE RELEASE RESPONSE message, the NG-RAN node shall be prepared to receive a PDU SESSION RESOURCE SETUP REQUEST message requesting establishment of a PDU session with a PDU Session ID corresponding to one of the PDU Session IDs that was present in the PDU Session Resource to Release List IE of the PDU SESSION RESOURCE RELEASE COMMAND message. If the User Location Information IE is included in the PDU SESSION RESOURCE RELEASE RESPONSE message, the AMF shall handle this information as specified in TS 23.501. For each PDU session for which the Secondary RAT Usage Information IE is included in the PDU Session Resource Release Response Transfer IE, the SMF shall handle this information as specified in TS 23.502. For each PDU session, if the Downlink TL Container IE for a QoS flow is included in the PDU Session Resource Release Command Transfer IE of the PDU SESSION RESOURCE RELEASE COMMAND message, the NG-RAN node shall, if supported, handle it as specified in TS 23.501 and shall include the Uplink TL Container IE for the indicated QoS flow in the PDU Session Resource Release Response Transfer IE as specified in TS 23.501.

The unsuccessful operation is specified in the successful operation section.

If the NG-RAN node receives a PDU SESSION RESOURCE RELEASE COMMAND message containing multiple PDU Session ID IEs (in the PDU Session Resource to Release List IE) set to the same value, the NG-RAN node shall initiate the release of one corresponding PDU session and ignore the duplication of the instances of the selected corresponding PDU sessions.