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full Contents for  TS 23.503  Word version:   16.4.1

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6.1.3.6  Policy controlWord-p. 47
QoS control refers to the authorization and enforcement of the maximum QoS that is authorized for a service data flow, for a QoS Flow or for the PDU Session. A service data flow may be either of IP type or of Ethernet type. PDU Sessions may be of IP type or Ethernet type or unstructured.
The PCF, in a dynamic PCC Rule, associates a service data flow template to an authorized QoS that is provided in a PCC Rule to the SMF. The PCF may also activate a pre-defined PCC Rule that contains that association.
The authorized QoS for a service data flow template shall include a 5QI and the ARP. For a 5QI of GBR or Delay-critical GBR resource type, the authorized QoS shall also include the MBR, GBR and may include the QoS Notification Control parameter (for notifications when authorized GFBR can no longer ( or can again) be fulfilled). For 5QI of Non-GBR resource type, the authorized QoS may include the MBR and the Reflective QoS Control parameter. The 5QI value can be standardized (i.e. referring to QoS characteristics as defined in TS 23.501, clause 5.7.3), pre-configured (i.e. referring to QoS characteristics configured in the RAN) or dynamically assigned (i.e. referring to QoS characteristics provided by the PCF as Explicitly signalled QoS Characteristics in the PDU Session related policy information described in clause 6.4).
NOTE 1:
Further details, special cases and additional parameters are described in clause 6.3.1.
QoS control also refers to the authorization and enforcement of the Session AMBR and default 5QI/ARP combination. The PCF may provide the authorized session AMBR and the default 5QI and ARP combination as part of the PDU Session information for the PDU Session to the SMF. The authorized Session AMBR and authorized default 5QI/ARP values takes precedence over other values locally configured or received at the SMF.
For policy control, the AF interacts with the PCF and the PCF interacts with the SMF as instructed by the AF. For certain events related to policy control, the AF shall be able to give instructions to the PCF to act on its own, i.e. based on the service information currently available. The following events are subject to instructions from the AF:
  • The authorization of the service based on incomplete service information;
  • NOTE 2:
    The QoS authorization based on incomplete service information is required for e.g. IMS session setup scenarios with available resources on originating side and a need for resource reservation on terminating side.
  • The immediate authorization of the service;
  • The gate control (i.e. whether there is a common gate handling per AF session or an individual gate handling per AF session component required);
  • The forwarding of QoS Flow level information or events (see clause 6.1.3.18).
To enable the binding functionality, the UE and the AF shall provide all available flow description information (e.g. source and destination IP address and port numbers and the protocol information).
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6.1.3.7  Service (data flow) prioritization and conflict handling
Service pre-emption priority enables the PCF to resolve conflicts where the activation of all requested active PCC rules for services would result in a cumulative authorized QoS which exceeds the Subscribed Guaranteed bandwidth QoS.
NOTE 1:
For example, the PCF may use the pre-emption priority of a service, the activation of which would cause the subscriber's authorized QoS to be exceeded. If this pre-emption priority is greater than that of any one or more active PCC rules, the PCF can determine whether the deactivation of any one or more such rules would allow the higher pre-emption priority PCC rule to be activated whilst ensuring the resulting cumulative QoS does not exceed a subscriber's Subscribed Guaranteed Bandwidth QoS.
If such a determination can be made, the PCF may resolve the conflict by deactivating those selected PCC rules with lower pre-emption priorities and accepting the higher priority service information from the AF. If such a determination cannot be made, the PCF may reject the service information from the AF.
NOTE 2:
Normative PCF requirements for conflict handling are not defined. Alternative procedures may use a combination of pre-emption priority and AF provided priority indicator.
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6.1.3.8  Termination actionWord-p. 48
The termination action indicates the action which the SMF instructs the UPF to perform for all PCC rules of a Charging key for which credit is no longer available. The functional description for termination actions is described in TS 32.255.
The SMF shall revert the termination action related instructions for the UPF for all PCC rules of a Charging key when credit is available again.
6.1.3.9  Handling of packet filters provided to the UE by SMF
Traffic mapping information is signalled to the UE by the SMF in the Packet Filter Sets of QoS rules as defined in TS 23.501.
The network shall ensure that the traffic mapping information signalled to UE reflects the QoS Flow binding of PCC rules, except for those extending the inspection beyond what can be signalled to the UE. The PCC rules may restrict what traffic is allowed compared to what is explicitly signalled to the UE. The PCF may, per service data flow filter, indicate that the SMF is required to explicitly signal the corresponding traffic mapping information to the UE, e.g. for the purpose of IMS precondition handling at the UE. In absence of that indication, it is an SMF decision whether to signal the traffic mapping information that is redundant from a traffic mapping point of view.
For QoS Flow for services with no uplink IP flows, there is no need to provide any UL filter to the UE that effectively disallows any useful packet flows in uplink direction.
The default QoS rule will either contain a Packet Filter Set that allows all UL packets or a Packet Filter Set that is generated from the UL SDF filters (and from the DL SDF filters if they are available) which have an indication to signal corresponding traffic mapping information to the UE.
NOTE:
If multiple PCC rules with an indication to signal corresponding traffic mapping information to the UE are bound to the QoS Flow associated with the default QoS rule, it is up to SMF implementation which one will be chosen to generate the default QoS rule. If the PCC rule that is chosen to generate the default QoS rule is removed/deactivated, another PCC rule bound to the QoS Flow associated with the default QoS rule will be used instead and the default QoS rule would be updated accordingly.
In the case of interworking with E-UTRAN connected to EPC, the specific aspects of the handling of packet filters at the SMF are described in clause 4.11.1 of TS 23.502.
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6.1.3.10  IMS emergency session support
PDU Sessions for IMS Emergency services are provided by the serving network to support IMS emergency when the network is configured to support emergency services. Emergency services are network services provided through an Emergency DNN and may not require a subscription depending on operator policies and local regulatory requirements. For emergency services, the architecture for the non-roaming case is the only applicable architecture model.
For emergency services, the N36 reference point does not apply. Emergency services are handled locally in the serving network.
For a PDU Session serving an IMS emergency session, the PCF makes authorization and policy decisions that restrict the traffic to emergency destinations, IMS signalling and the traffic to retrieve user location information (in the user plane) for emergency services. A PDU Session serving an IMS emergency session shall not serve any other service and shall not be converted to/from any PDU Session serving other services. The PCF shall determine based on the DNN if a PDU Session concerns an IMS emergency session.
The PCC Rule Authorization function selects QoS parameters that allow prioritization of IMS Emergency sessions. If an IMS Emergency session is prioritized the QoS parameters in the PCC Rule shall contain an ARP value that is reserved for intra-operator use of IMS Emergency services. The PCF does not perform subscription check; instead it utilizes the locally configured operator policies to make authorization and policy decisions.
NOTE 1:
Reserved value range for intra-operator use is defined in TS 23.501.
For an emergency DNN, the PCF does not perform subscription check; instead it utilizes the locally configured operator policies to make authorization and policy decisions.
It shall be possible for the PCF to verify that the IMS service information is associated with a UE IP address belonging to an emergency DNN. If the IMS service information does not contain an emergency related indication and the UE IP address is associated with an emergency DNN, the PCF shall reject the IMS service information provided by the P CSCF (and thus to trigger the release of the associated IMS session), see TS 23.167.
In addition, the PCF shall provide the IMEI and the subscriber identifiers (IMSI, MSISDN) (if available), received from the SMF at PDU Session establishment, if so requested by the P-CSCF.
If the PCF removes all PCC Rules with a 5QI other than the default 5QI and the 5QI used for IMS signalling, the SMF shall start a configurable inactivity timer (e.g., to enable PSAP Callback session). When the configured period of time expires the SMF shall terminate the PDU Session serving the IMS Emergency session as defined in TS 23.502. If the SMF receives new PCC rule(s) with a 5QI other than the default 5QI and the 5QI used for IMS signalling for the PDU Session serving the IMS Emergency session, the SMF shall cancel the inactivity timer.
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6.1.3.11  Multimedia Priority Service supportWord-p. 49
Multimedia Priority Services (MPS) is defined in TS 23.501, TS 23.502 and in TS 23.228, utilising the architecture defined for 5GS.
Subscription data for MPS is provided to PCF through the N36/Nudr. To support MPS service, the PCF shall subscribe to changes in the MPS subscription data for Priority PDU connectivity service. Dynamic invocation for MPS provided from an AF using the Priority indicator over N5/Npcf takes precedence over MPS subscription.
For dynamic invocation of MPS service, the PCF shall generate the corresponding PCC rule(s) with the ARP and 5QI parameters as appropriate for the prioritized service, as defined in TS 23.501.
Whenever one or more AF sessions of an MPS service are active within the same PDU Session, the PCF shall ensure that the ARP priority level of the QoS Flow for signalling as well as the QoS Flow associated with the default QoS rule is at least as high as the highest ARP priority level used by any authorized PCC rule belonging to an MPS service. If the ARP pre-emption capability is enabled for any of the authorized PCC rules belonging to an MPS service, the PCF shall also enable the ARP pre-emption capability for the QoS Flow for signalling as well as the QoS Flow associated with the default QoS rule.
In the case of IMS MPS, in addition to the above, the following QoS Flow handling applies:
  • At reception of the indication from subscription information that the IMS Signalling Priority is set for the PDU Session or at reception of service authorization from the P-CSCF (AF) including an MPS session indication and the service priority level as defined in TS 23.228, the PCF shall (under consideration of the requirement described in clauses 5.16.5 and 5.22.3 in TS 23.501) modify the ARP in all the PCC rules that describe the IMS signalling traffic to the value appropriate for IMS Multimedia Priority Services, if upgrade of the QoS Flow carrying IMS Signalling is required. To modify the ARP of the QoS Flow associated with the default QoS rule the PCF shall modify the Authorized default 5QI/ARP.
  • When the PCF detects that the P-CSCF (AF) released all the MPS session and the IMS Signalling Priority is not set for the PDU Session the PCF shall consider changes of the requirement described in clauses 5.16.5 and 5.22.3 in TS 23.501 and modify the ARP in all PCC rules that describe the IMS signalling traffic to an appropriate value according to PCF decision. The PCC rules bound to the QoS Flow associated with the default QoS rule have to be changed accordingly.
NOTE:
To keep the PCC rules bound to this QoS Flow, the PCF can either modify the ARP of these PCC rules accordingly or set the Bind to QoS Flow associated with the default QoS rule.
The Priority PDU connectivity service targets the ARP and/or 5QI of the QoS Flows, enabling the prioritization of all traffic on the same QoS Flow.
For non-MPS service, the PCF shall generate the corresponding PCC rule(s) as per normal procedures (i.e. without consideration whether the MPS Priority PDU connectivity service is active or not), and shall upgrade the ARP/5QI values suitable for MPS when the Priority PDU connectivity service is invoked. When the Priority PDU connectivity service is revoked, the PCF shall change the ARP/5QI values modified for the Priority PDU connectivity service to an appropriate value according to PCF decision.
The PCF shall, at the activation of the Priority PDU connectivity service:
  • modify the ARP of PCC rules installed before the activation of the Priority PDU connectivity service to the ARP as appropriate for the Priority PDU connectivity service under consideration of the requirement described in clause 5.16.5 of TS 23.501; and
  • if modification of the 5QI of the PCC rule(s) is required, modify the 5QI of the PCC rules installed before the activation of the Priority PDU connectivity service to the 5QI as appropriate for this service.
The PCF shall, at the deactivation of the Priority PDU connectivity service modify any 5QI and ARP value to the value according to the PCF policy decision.
For PCC rules modified due to the activation of Priority PDU connectivity service:
  • modify the ARP to an appropriate value according to PCF decision under consideration of the requirement described in clauses 5.16.5 and 5.22.3 in TS 23.501; and
  • if modification of the 5QI of PCC rule(s) is required, modify the 5QI to an appropriate value according to PCF decision.
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6.1.3.12  RedirectionWord-p. 50
Redirection of uplink application traffic is an option applicable in SMF or in UPF.
PCF may control redirection by provisioning and modifying dynamic PCC rules over the N7 interface, or activate/deactivate the predefined redirection policies in SMF. The PCF may enable/disable redirection and set a redirect destination for every dynamic PCC rule. Redirect information (redirection enabled/disabled and redirect destination) within a PCC Rule instructs the SMF whether or not to perform redirection towards a specific redirect destination. The redirect destination may be provided as part of the dynamic PCC Rule, or may be preconfigured in the SMF or UPF. A redirect destination provided in a dynamic PCC Rule overrides the redirect destination preconfigured in the SMF or UPF for this PCC Rule.
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6.1.3.13  Resource sharing for different AF sessions
The P-CSCF (i.e. AF) may indicate to the PCF that media of an AF session may share resources with media belonging to other AF sessions according to TS 23.228. For every media flow, the P-CSCF may indicate that the media flow may share resources in both directions or in one direction only (UL or DL).
The PCF makes authorization and policy decisions for the affected AF sessions individually and generates a PCC rule for every media flow in any AF session.
If the PCF received identical indication(s) for resource sharing for multiple AF sessions, the PCF may request the SMF to realize resource sharing for the corresponding set of PCC rules. The PCF provides a DL and/or UL sharing indication with the same value for those PCC rules that are candidate to share resources according to the direction of resource sharing indicated by the AF.
For each direction, the SMF shall take the highest GBR value from each set of PCC rules related with the same sharing indication for this direction and bound to the same QoS Flow and uses that value as input for calculating the GFBR of the QoS Flow. For each direction, the SMF may take the MBR value of the most demanding PCC rule included in each set of PCC rules related with the same sharing indication for this direction and bound to the same QoS Flow and uses that as input for calculating the MFBR of the QoS Flow.
The AF session termination or modification procedure that removes media flows triggers the removal of the corresponding PCC rules from the SMF. The SMF shall recalculate the GFBR (and MFBR) value of the QoS Flow whenever a set of PCC rules with the same sharing indication changes.
Resource sharing is applied as long as there are at least two active PCC rules with the same sharing indication bound to the same QoS Flow.
Resource sharing for different AF sessions is possible only if the P-CSCF, the PCF and the SMF support it.
NOTE:
This procedure assumes that applications/service logic must do the necessary coordination, e.g. pause sending or employ gating, to avoid service data flows interfering and to ensure that multiple flows comply with the combined QoS parameters.
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6.1.3.14  Traffic steering controlWord-p. 51
Traffic steering control is triggered by the PCF initiated request and consists of steering the detected service data flows matching application detection filters or service data flow filter(s) in PCC Rules. The traffic steering control consists in:
  • diverting (at DNAI(s) provided in PCC rules) traffic matching traffic filters provided by the PCF, as described in TS 23.501, clause 5.6.7.
  • applying a specific N6 traffic steering policy for the purpose of steering the subscriber's traffic to appropriated N6 service functions deployed by the operator or a 3rd party service provider as described below.
The PCF uses one or more pieces of information such as network operator's policies, user subscription, user's current RAT, network load status, application identifier, time of day, UE location, DNN, related to the subscriber session and the application traffic as input for selecting a traffic steering policy.
The PCF controls traffic steering by provisioning and modifying traffic steering control information in PCC rules. Traffic steering control information consists of a traffic description and a reference to a traffic steering policy that is configured in the SMF.
The SMF instructs the UPF to perform necessary actions to enforce the traffic steering policy referenced by the PCF. The actual traffic steering applies at the UPF. For enforcing the traffic steering policy, the UPF may support traffic steering related functions as defined by other standard organizations. The mechanism used for routing the traffic over N6 is out of 3GPP scope.
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6.1.3.15  Resource reservation for services sharing priority
An AF may indicate to the PCF that a media flow of an AF session is allowed to use the same priority as media flows belonging to other AF sessions (instead of the service priority provided for this media flow). In this case, the AF will provide a priority sharing indicator in addition to the application identifier and the service priority. For MCPTT, the service priority and the priority sharing indicator are defined in TS 23.179 [6]. The priority sharing indicator is used to indicate what media flows are allowed to share priority.
The PCF makes authorization and policy decisions for the affected AF sessions individually and generates a PCC rule for every media flow as specified in clause 6.1.1.3. The application identifier and the service priority are used to calculate the ARP priority. The AF may also provide suggested pre-emption capability and vulnerability values per media flow to the PCF. The ARP pre-emption capability and the ARP pre-emption vulnerability are set according to operator policies and regulatory requirements, also taking into consideration the application identifier and suggested values, when provided by the AF. The priority sharing indicator is stored for later use.
For PCC rules with the same 5QI assigned and having an associated priority sharing indicator, the PCF shall try to make authorization and policy decisions taking the priority sharing indicator into account and modify the ARP of these PCC rules as follows, (the original ARP values are stored for later use):
  • The modified ARP priority is set to the highest of the original priority among all the PCC rules that include the priority sharing indicator;
  • The modified ARP pre-emption capability is set if any of the original PCC rules have the ARP pre-emption capability set;
  • The modified ARP pre-emption vulnerability is set if all the original PCC rules have the ARP pre-emption vulnerability set.
If the PCF receives an indication that a PCC rule provisioning or modification failed (due to resource reservation failure) then, the PCF may apply pre-emption and remove active PCC rules from the SMF and then retry the PCC rule provisioning or modification. If the PCF does not apply pre-emption, the AF is notified using existing procedures that the resource reservation for the new media flow failed.
The AF may optionally provide pre-emption control information, including pre-emption capability and vulnerability values, in addition to the priority sharing indicator to the PCF. If so, the PCF shall apply pre-emption and remove active PCC rules according to this information when receiving an indication that a PCC rule provisioning or modification failed. The pre-emption control information indicates:
  • whether media flows sharing priority are candidates to being pre-empted taking into account pre-emption capability and vulnerability values;
  • how to perform pre-emption among multiple potential media flow candidates of same priority: most recently added media flow, least recently added media flow, media flow with highest requested bandwidth in the AF request.
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6.1.3.16  3GPP PS Data OffWord-p. 52
This feature, when activated by the user, prevents traffics via 3GPP access except for 3GPP PS Data Off Exempt Services. The 3GPP PS Data Off Exempt Services are a set of operator services, defined in TS 22.011 and TS 23.221, that are the only allowed services in both downlink and uplink direction when the 3GPP PS Data Off feature has been activated by the user.
When PCF is deployed, it shall be able to configure the list(s) of 3GPP PS Data Off Exempt Services for 3GPP access, and the Policy Control Request Trigger of 3GPP PS Data Off status change used to inform the PCF from SMF about every change of the 3GPP PS Data Off status.
NOTE 1:
The PCF can be configured with a list(s) of 3GPP PS Data Off Exempt Services per DNN. The list(s) of 3GPP PS Data Off Exempt Services for an DNN can also be empty, or can allow for any service within that DNN, according to operator policy.
NOTE 2:
For the PDU Session used for IMS services, the 3GPP Data Off Exempt Services are enforced in the IMS domain as specified TS 23.228. Policies configured in the PCF need to ensure that IMS services are allowed when the 3GPP Data Off status of the UE is set to "activated", e.g. by treating any service within a well-known IMS DNN as 3GPP PS Data Off Exempt Services.
When the PCF is informed about the activation of 3GPP PS Data Off, it shall update the PCC rules in such a way that for 3GPP access only packets for services belonging to the list(s) of 3GPP PS Data Off Exempt Services are forwarded while all other packets are discarded. Packets sent over non-3GPP access are not affected, and in the case of MA PDU Session, this is ensured by the MA PDU Session Control policy, e.g. for packets not belonging to the 3GPP Data Off Exempt Services, PCF provides PCC rule containing Steering Mode "Active-Standby" with active access as non-3GPP access and no standby access for downlink and uplink direction.
NOTE 3:
For non MA PDU Sessions, in order for the SMF/UPF to prevent the services that do not belong to the list(s) of 3GPP PS Data Off Exempted Services, if the services are controlled by dynamic PCC rules, the PCF could modify the PCC rules by setting the gate status to "closed" for downlink and optionally uplink direction in all active dynamic PCC rules or remove those dynamic PCC rules. If the services are controlled by predefined PCC rules, the PCF can deactivate those predefined PCC rules. PCC rule with wild-carded service data flow filters can be among the PCC rules that are modified, removed or deactivated in that manner. In this case, it can be necessary that the PCF at the same time installs or activates PCC rules for data-off exempt services.
NOTE 4:
For example, for non MA PDU Sessions, four PCC rules (A, B, C, D) are active for a PDU Session with PCC rule A representing a 3GPP PS Data Off Exempt Service. When 3GPP PS Data Off is activated, the PCF could either modify PCC rules B, C and D if they are dynamic PCC rules by closing the gate in downlink and optionally uplink direction or remove/deactivate PCC rules B, C and D if they are predefined PCC rules. PCC rule A does not need to be changed as it represents 3GPP PS Data Off Exempt Service. Assuming that PCC rule B contained wild-carded service data flow filters which has enabled some 3GPP PS Data Off Exempt Service is removed or deactivated, an additional PCC rule E can be installed or activated as well to enable downlink and optionally uplink traffic for that 3GPP PS Data Off Exempt Service.
NOTE 5:
The network configuration can ensure that at least one PCC Rule is activated for the PDU Session when Data Off is activated in order to avoid deletion of an existing PDU Session or in order not to fail a PDU Session establishment.
When the PCF receives service information from the AF, in addition to what is specified in clause 6.2.1, PCF shall check if the requested service information belongs to the 3GPP PS Data Off Exempt Services. If the requested service belongs to 3GPP PS Data Off Exempt Services or if the service traffic can be sent over non-3GPP access, PCF shall continue as specified in clause 6.2.1. If the requested service doesn't belong to the 3GPP PS Data Off Exempt Services and the PDU Session is established only over 3GPP access, PCF shall reject the service request.
When the PCF is informed about the deactivation of 3GPP PS Data Off, it shall perform policy control decision as specified in clause 6.2.1 and perform PCC rule operations as specified in clause 6.3.2 to make sure that the services are allowed according to user's subscription and operator policy (irrespective of whether they belong to the list(s) of 3GPP PS Data Off Exempt Services).
When PCF is not deployed, predefined PCC rules, e.g. for non MA PDU Sessions, can be configured in the SMF to ensure the following:
  • when the SMF is informed about activation of 3GPP PS Data Off, the SMF ensures in UPF only downlink and optionally uplink packets for services belonging to the list(s) of 3GPP PS Data Off Exempt Services are forwarded while all other downlink and uplink packets are discarded, and
  • When SMF is informed about deactivation of 3GPP PS Data Off, the SMF ensures in UPF downlink and uplink packets are forwarded according to the operator policy for the subscriber.
NOTE 6:
For example, the SMF can be configured with two sets of predefined PCC rules: one set for UE 3GPP PS Data Off status "inactive" and another set for UE 3GPP PS Data Off status "active". The set of predefined PCC rules for UE 3GPP PS Data Off status "active" can be equivalent to the set of predefined PCC rules for UE with 3GPP PS Data Off status "inactive" with the following two differences: All services belonging to the list(s) of 3GPP PS Data Off Exempt Services can be represented by PCC rule(s) which allows the traffic to pass while in all other PCC rules (not belonging to the list(s) of 3GPP PS Data Off Exempt Services) the gate status can be "closed" for downlink and optionally uplink direction. When the SMF is informed about the change of UE 3GPP PS Data Off status, it can replace the currently active set of predefined PCC rules with the other set of predefined PCC rules.
When the UE 3GPP PS Data Off status is "active" and a handover from one access-system to another occurs, the PCF performs the above operations so that the downlink and optionally uplink traffic for services not belonging to the list(s) of 3GPP PS Data Off Exempt Services is only prevented via the 3GPP access.
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6.1.3.17  Policy decisions based on spending limitsWord-p. 53
Policy decisions based on spending limits is a function that allows PCF taking actions related to the status of policy counters that are maintained in the CHF.
The PCF uses the CHF selection mechanism defined in TS 23.501 to select the CHF that provides policy counters for spending limits for a PDU session. The PCF shall also provide the selected CHF address(es) to the SMF in the PDU Session related policy information.
The identifiers of the policy counters that are relevant for a policy decision in the PCF may be stored in the PCF or possibly in UDR. The PCF is configured with the actions associated with the policy counter status that is received from CHF.
The PCF may retrieve the status of policy counters in the CHF using the Initial or Intermediate Spending Limit Report Retrieval Procedure. The CHF provides the current status of the policy counters to the PCF. The CHF may in addition provide one or more pending statuses for a policy counter together with the time they have to be applied. The PCF shall immediately apply the current status of a policy counter. A pending status of a policy counter shall autonomously become the current status of a policy counter at the PCF when the indicated corresponding time is reached. Subsequently provided information for pending statuses of a policy counter shall overwrite the previously received information.
The PCF may subscribe to spending limit reporting for policy counters from the CHF using the Initial or Intermediate Spending Limit Report Retrieval procedure. If spending limit reporting for a policy counter is enabled, the CHF shall notify the PCF of changes in the status of this policy counter (e.g. daily spending limit of $2 reached) and optionally pending statuses of this policy counter together with their activation time (e.g. due to a billing period that will expire at midnight). The PCF may cancel spending limit reporting for specific policy counter(s) using the Intermediate Spending Limit Report Retrieval procedure, or for all policy counter(s) using the Final Spending Limit Report Retrieval procedure.
The PCF uses the status of each relevant policy counter, and optional pending policy counter statuses if known, as input to its policy decision to apply operator defined actions, e.g. change the QoS (e.g. downgrade Session-AMBR), modify the PCC Rules to apply gating or change charging conditions.
The CHF may report to the PCF the removal of the subscriber from the CHF system, and the PCF shall remove all the policy counters of the subscriber accordingly.
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6.1.3.18  Event reporting from the PCFWord-p. 54
The AF may subscribe/unsubscribe to notifications of events from the PCF for the PDU Session to which the AF session is bound.
The events that can be subscribed by the AF are listed in Table 6.1.3.18-1.
Event
Description
Conditions for reporting
Availability for Rx PDU Session (NOTE 2)
Availability for N5 PDU Session
Availability for Bulk Subscription (NOTE 1)

PLMN Identifier Notification
The PLMN identifier where the UE is currently located.
AF
Yes
Yes
Yes
Change of Access Type
The Access Type and, if applicable, the RAT Type of the PDU Session has changed.
AF
Yes
Yes
Yes
EPS fallback
EPS fallback is initiated
AF
Yes
Yes
No
Signalling path status
The status of the resources related to the signalling traffic of the AF session.
AF
Yes
Yes
No
Access Network Charging Correlation Information
The Access Network Charging Correlation Information of the resources allocated for the AF session.
AF
Yes
Yes
No
Access Network Information Notification
The user location and/or timezone when the PDU Session has changed in relation to the AF session.
AF
Yes
Yes
No
Reporting Usage for Sponsored Data Connectivity
The usage threshold provided by the AF has been reached; or the AF session is terminated.
AF
Yes
Yes
No
Service Data Flow deactivation
The resources related to the AF session are released.
AF
Yes
Yes
No
Resource allocation outcome
The outcome of the resource allocation related to the AF session.
AF
Yes
Yes
No
QoS targets can no longer (or can again) be fulfilled
The QoS targets can no longer (or can again) be fulfilled by the network for (a part of) the AF session.
AF
No
Yes
No
QoS Monitoring parameters
The QoS Monitoring parameter(s) (e.g. UL packet delay, DL packet delay or round trip packet delay) are reported to the AF according to the QoS Monitoring reports received from the SMF.
AF
No
Yes
No
Out of credit
Credit is no longer available.
AF
Yes
Yes
No
5GS Bridge information Notification (NOTE 3)
5GS Bridge information that has been received by PCF from SMF.
AF
No
Yes
No

NOTE 1:
Additional parameters for the subscription as well as reporting related to these events are described in TS 23.502.
NOTE 2:
Applicability of Rx is described in Annex C.
NOTE 3:
5GS Bridge information is described in clause 6.1.3 UE-DS-TT Residence Time is only provided if a DS-TT port is detected

If an AF requests the PCF to report the PLMN identifier where the UE is currently located, then the PCF shall provide the PLMN identifier to the AF if available. Otherwise, the PCF shall provision the corresponding PCC rules, and the Policy Control Request Trigger to report PLMN change to the SMF. The PCF shall, upon receiving the PLMN identifier from the SMF forward this information to the AF.
If an AF requests the PCF to report on the change of Access Type, the PCF shall provide the corresponding Policy Control Request Trigger to the SMF to enable the report of the Change in Access Type to the PCF. The PCF shall, upon reception of information about the Access Type the user is currently using and upon indication of change of Access Type, notify the AF on changes of the Access Type and forward the information received from the SMF to the AF. The change of the RAT Type shall also be reported to the AF, even if the Access Type is unchanged. For MA PDU Session the Access Type information may include two Access Type information that the user is currently using.
If an AF requests the PCF to report on the signalling path status, for the AF session, the PCF shall, upon indication of removal of PCC Rules identifying signalling traffic from the SMF report it to the AF.
If an AF requests the PCF to report Access Network Charging Correlation Information, the PCF shall provide to the AF the Access Network Charging Correlation Information, which allows to identify the usage reports that include measurements for the Service Data Flow(s), once the Access Network Charging Correlation Information is known at the PCF.
If an AF requests the PCF to report Access Network Information (i.e. the User Location Report and/or the UE Timezone Report) at AF session establishment, modification or termination, the PCF shall set the Access Network Information report parameters in the corresponding PCC rule(s) and provision them together with the corresponding Policy Control Request Trigger to the SMF. For those PCC rule(s) based on preliminary service information the PCF may assign the 5QI and ARP of the QoS Flow associated with the default QoS rule to avoid signalling to the UE. The PCF shall, upon receiving an Access Network Information report corresponding to the AF session from the SMF, forward the Access Network Information as requested by the AF. For AF session termination the communication between the AF and the PCF shall be kept alive until the PCF report is received.
If an AF requests the PCF to report the Usage for Sponsored Data Connectivity, the PCF shall provision the corresponding PCC rules, and the Policy Control Request Trigger to the SMF. If the usage threshold provided by the AF has been reached or the AF session is terminated, the PCF forwards such information to the AF.
If an AF requests the PCF to report the Service Data Flow deactivation, the PCF shall report the release of resources corresponding to the AF session. The PCF shall, upon being notified of the removal of PCC Rules corresponding to the AF session from the SMF, forward this information to the AF. The PCF shall also forward, if available, the reason why the resources are released, the user location information and the UE Timezone.
If an AF requests the PCF to report the Resource allocation outcome, the PCF shall report the outcome of the resource allocation of the Service Data Flow(s) related to the AF session. The AF may request to be notified about successful or failed resource allocation.
If an AF requests the PCF to report when the QoS targets can no longer (or can again) be fulfilled for a particular media flow, the PCF shall set the QNC indication in the corresponding PCC rule(s) that includes a GBR or delay critical GBR 5QI value and provision them together with the corresponding Policy Control Request Trigger to the SMF. At the time, the SMF notifies that GFBR can no longer (or can again) be guaranteed for a QoS Flow to which those PCC Rule(s) are bound, the PCF shall report to the AF the affected media flow and provides the indication that QoS targets can no longer (or can again) be fulfilled. If additional information is received with the notification from SMF (see clause 5.7.2.4 of TS 23.501), the PCF shall forward it to the AF.
If an AF requests the PCF to report on the event of the 5GS Bridge information Notification, for the AF session, the PCF shall, request the SMF to report on the trigger of 5GS Bridge information available as described in the clause 6.1.3.5. Upon reception of the 5G bridge information, the PCF forwards this information to the TSN AF.
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6.1.3.19  Mission Critical Services supportWord-p. 56
Mission Critical Services are defined in TS 23.501, TS 23.502 and in TS 23.280, utilising the architecture defined for 5GS.
Subscription data for MCX services are provided to PCF through the N36/Nudr. To support MCX services, the PCF shall subscribe to changes in the MCX services subscription data for Priority PDU connectivity service. Dynamic invocation for MCX services provided from an AF using the Priority indicator over N5/Npcf takes precedence over the MCX services subscription.
For MCX services the session management relate policy control functionality of the Policy and Charging control framework for the 5G system is as defined in clause 6.1.3.11 for Multimedia Priority Service.
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6.1.3.20  Access Traffic Steering, Switching and Splitting [R16]Word-p. 57
As specified in TS 23.501, the Access Traffic Steering, Switching and Splitting (ATSSS) feature is an optional feature that may be supported by the UE and the 5GC network. The ATSSS feature enables a multi-access PDU Connectivity Service, which can exchange PDUs between the UE and a data network by simultaneously using one 3GPP access network and one non-3GPP access network.
The PCF is informed of the ATSSS capabilities of a MA PDU Session by the SMF, as defined in TS 23.501, clause 5.32.2. The ATSSS capabilities are both the Steering Mode and the Steering Functionality.
The PCF control of Access Traffic Steering, Switching and Splitting for a detected service data flow (SDF) is enabled by including Multi-Access PDU (MA PDU) Session Control information in the PCC rule. This allows the PCF to control:
  • The Steering Mode that is used to steer/switch/split the detected SDF. The available Steering Modes are defined in TS 23.501.
  • The Steering Functionality that is used for the detected SDF, e.g. the MPTCP functionality or the ATSSS-LL functionality defined in TS 23.501.
  • Charging information depending on what Access Type is used for a detected SDF.
  • Usage Monitoring information depending on what Access Type is used for a detected SDF.
The rest of the information in the PCC Rule apply to the SDF as such and are not dependent on what Access Type is used for a packet.
The MA PDU Session Control information in the PCC rules is used by the SMF in order to create applicable N4 rules for the UPF and ATSSS rules for the UE, as described in TS 23.501. The ATSSS rules are sent to UE via NAS when the MA PDU Session is created or updated by the SMF/PCF, as described in TS 23.501 and TS 23.502.
The PCF may also provide URSP rules to the UE for instructing the UE to establish a MA PDU Session, as described in clause 6.6.2.
The PCF control of PDU session level Usage Monitoring depending on what access type is used to carry the traffic is enabled by providing Usage Monitoring control related information per access in the PDU Session related policy control information (as described in clause 6.4).
If the MA PDU session is capable of MPTCP and ATSSS-LL with any Steering Mode in the downlink and MPTCP and ATSSS-LL with Active-Standby in the uplink, then the PCF shall provide a PCC Rule for non-MPTCP traffic. This PCC Rule contains a "match all" SDF template, the lowest precedence, the Steering Functionality set to "ATSSS-LL" and the Steering Mode set to "Active-Standby" for the uplink direction, and the Steering Functionality set to "ATSSS-LL" and the Steering Mode set to any supported steering mode for the downlink direction.
If the MA PDU session is capable of MPTCP and ATSSS-LL with Active-Standby in the uplink and downlink, then the PCF shall provide a PCC Rule for non-MPTCP traffic. This PCC Rule contains a "match all" SDF template, the lowest precedence, the Steering Functionality set to "ATSSS-LL" and the Steering Mode set to "Active-Standby" for the uplink direction and the downlink direction.
These PCC Rules are used by the SMF to generate an ATSSS rule for the UE and an N4 rule for the UPF to route the non-MPTCP traffic of the MA PDU Session in the uplink and downlink direction respectively.
NOTE:
The PCF can also use the ATSSS capability of the MA PDU Session to provide PCC Rules containing SDF template for some specific non-MPTCP traffic other than the PCC Rule containing a "match all" SDF template. This allows the operator to apply different policies e.g. charging key to non-MPTCP traffic other than the non-MPCTP traffic matching the "match all" PCC Rule.
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6.1.3.21  QoS Monitoring to assist URLLC Service [R16]
The QoS Monitoring for URLLC refers to the real time packet delay measurement between the UE and the UPF for a QoS Flow corresponding to an URLLC service.
The PCF generates the authorized QoS Monitoring policy for the service data flow based on the QoS Monitoring request if received from the AF. The QoS Monitoring policy includes the following:
  • QoS parameters to be measured (DL, UL or round trip packet delay);
  • frequency of reporting (event triggered, periodic, when no packet delay measurement result is received for a delay exceeding a threshold, or when the PDU Session is released):
    • if the reporting frequency is event triggered:
      • the corresponding reporting threshold to each QoS parameter;
      • minimum waiting time between subsequent reports;
    • if the reporting frequency is periodic, the reporting period;
    • threshold for reporting packet delay measurement failure;
  • information about the target of the QoS Monitoring reports (e.g. either to the PCF or the AF indicated as
  • Notification Target Address + Notification Correlation ID as specified in TS 23.502, clause 4.15.1).
The PCF includes the authorized QoS Monitoring policy in the PCC rule and provides it to the SMF.
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6.1.3.22  AF session with required QoS [R16]Word-p. 58
The AF may request that a data session to a UE is set up with a specific QoS (e.g. low latency or jitter) and priority handling. The AF can request the network to provide QoS for the AF session based on the service requirements with the help of a QoS reference parameter which refers to pre-defined QoS information. When the PCF authorizes the service information from the AF and generates a PCC rule, it derives the QoS parameters of the PCC rule based on the service information and the indicated QoS reference parameter.
NOTE 1:
A SLA has to be in place between the operator and the ASP defining the possible QoS levels and their charging rates. For each of the possible pre-defined QoS information sets, the PCF needs to be configured with the corresponding QoS parameters and their values as well as the appropriate Charging key (or receive this information from the UDR).
The AF may change the QoS by providing a different QoS reference parameter while the AF session is ongoing. If this happens, the PCF shall update the related QoS parameter sets in the PCC rule accordingly.
If the PCF gets informed about Policy Control Request Triggers relevant for the AF session, the PCF shall inform the AF about it as defined in clause 6.1.3.18.
If an AF session can adjust to different QoS parameter combinations, the AF may provide Alternative Service Requirements containing one or more QoS reference parameters in a prioritized order (which indicates the preference of the QoS requirements with which the service can operate). If so, the AF shall also subscribe to receive notifications when the QoS targets can no longer (or can again) be fulfilled from the PCF as described in clause 6.1.3.18.
When the PCF authorizes the service information from the AF and generates a PCC rule, it shall also derive Alternative QoS parameter sets for this PCC rule based on the QoS reference parameters in the Alternative Service Requirements.
The PCF shall enable QoS Notification Control and include the derived Alternative QoS parameter sets (in the same prioritized order indicated by the AF) in the PCC rule sent to the SMF. When the PCF notifies the AF that QoS targets can no longer (or can again) be fulfilled (as described in clause 6.1.3.18) the PCF shall include the QoS reference parameter corresponding to the Alternative QoS parameter set referenced by the SMF.
NOTE 2:
The AF behaviour is out of the scope of this TS but can include adaptation to the change of QoS (e.g. rate adaptation) as well as application layer signalling with the UE.
The AF may change the Alternative Service Requirements while the AF session is ongoing. If this happens, the PCF shall update the Alternative QoS parameter sets in the PCC rule accordingly.
The AF may indicate to the PCF that the UE does not need to be informed about changes related to Alternative QoS Profiles. With this indication received from the AF, the PCF decides whether to disable the notifications to the UE when changes related to the Alternative QoS Profiles occur and sets the Disable UE notifications at changes related to Alternative QoS Profiles parameter in the PCC rule accordingly.
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6.1.3.23  Support of integration with Time Sensitive Networking [R16]Word-p. 59
Time Sensitive Networking (TSN) support is defined in TS 23.501, where the 5GS represents virtual TSN bridge(s) based on the defined granularity model. The TSN AF and PCF interact to perform QoS mapping as described in clause 5.28.4 of TS 23.501.
The PCF provides the following parameters to the TSN AF:
  • 5GS bridge information:
  • 5GS Bridge address (unique MAC address that identifies the bridge used to derive the bridge ID);
  • UE-DS-TT Residence time;
  • Port Management Information Container and the related port number:
  • Ethernet port of DS-TT;
  • port number of the Ethernet port;
  • MAC address of the Ethernet port.
The TSN AF may use this information to construct IEEE managed objects, to interwork with IEEE TSN networks.
The TSN AF decides the TSN QoS information (i.e. priority, delay and maximum TSC Burst Size) based on the received the configuration information of 5GS Bridge from the CNC as defined in clause 5.28.2 of TS 23.501, the bridge delay information at the TSN AF and the UE-DS-TT Residence time.
The PCF receives a request from the TSN AF that shall include:
  • UE MAC address (i.e. MAC address of the DS-TT port) for PDU session.
The PCF receives a request from the TSN AF that may include:
  • Service data flow filter containing the Flow Descriptions (e.g. Ethernet PCP, VLAN ID, destination MAC address of the TSN stream);
  • TSN QoS Parameters for the service data flow:
    • TSN QoS container: describes the TSC stream traffic characteristics (burst arrival time, periodicity, (both in reference to TSN GM), and Flow direction needed for TSCAI determination (as described in clauses 5.27 and 5.28 of TS 23.501);
    • TSN QoS information, i.e. priority, maximum TCS Burst Size and delay.
  • Port Management Information Container and target port number.
The PCF performs Session binding using the UE MAC address, and then the PCF derives the TSN QoS information into a 5QI. The PCF generates a PCC Rule with service data flow filter containing the Flow Descriptions provided by the TSN AF, the mapped 5QI and the associated TSC QoS container as received from the AF. The SMF binds the PCC Rule to a QoS Flow as defined in clause 6.1.3.2.4.
NOTE:
TSC burst size can also represent the burst sizes of multiple TSN streams that have been aggregated.
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