6.11 Traffic Steering Control Information

23.2033GPPPolicy and charging control architectureRelease 17TS

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

6.11.1 General

The traffic steering control information comprises the information that is required to enable traffic steering for a detected application or service data flow. The traffic steering control information is transferred:

– From the PCRF to the PCEF within PCC rules over Gx reference point;

– From the PCRF to the TDF within ADC rules over Sd reference point;

– From the PCRF to the TSSF within ADC rules over St reference point.

NOTE 1: In this release of the specification, traffic steering control information does not contain the IP-CAN specific parameters such as e.g. RAT type, which may be needed by the (S)Gi-LAN service functions.

Table 6.11 lists the components of traffic steering control information, and their corresponding information names in PCC/ADC rule.

Table 6.11: Traffic steering control information

Component of traffic steering control information	Corresponding information name in ADC rule (NOTE 1)	Corresponding information name in PCC rule (NOTE 2)
Rule Name	ADC Rule Identifier	Rule identifier
Description of Traffic	Application Identifier or Service data flow filter list	Service Data Flow Template
Traffic steering policy identifier(s) (NOTE 3)	Traffic steering policy identifier(s) (NOTE 3)	Traffic steering policy identifier(s) (NOTE 3)
Precedence	Precedence	Precedence
NOTE 1: The information definition refers to Table 6.8. NOTE 2: The information definition refers to Table 6.3. NOTE 3: The Traffic steering policy identifier can be different for uplink and downlink direction. If two Traffic steering policy identifiers are provided, then one is for uplink direction, while the other one is for downlink direction.

The Traffic Steering Policy Identifier is a reference to traffic steering policy locally configured at the PCEF/TDF/TSSF. The traffic steering policy identifies, explicitly or implicitly, a specific set of service functions and their order via which the traffic, identified by the description of traffic included in the traffic steering control information, needs to be steered in the (S)Gi-LAN.

For traffic steering control at the PCEF, the PCC Rule operations described in the clause 6.3.2 apply.

For traffic steering control at the TDF, the ADC Rule operations over Sd described in the clause 6.8.2 apply.

For traffic steering control at the TSSF, the Traffic Steering Control operations over St described in the clause 6.11.2 apply.

NOTE 2: In order for PCEF/TDF to measure the user plane traffic that is sent to a specific set of service functions, identified by a Traffic Steering Policy Identifier, a specific Charging Key or generic Charging Key and a specific Service Identifier is assigned to the PCC/ADC rule per each Traffic Steering Policy Identifier for which separate measurements are needed and the applicable measurement type as required. In case of Service Identifier usage, the PCC/ADC Rule also includes service identifier level reporting.

6.11.2 Traffic Steering Control Operations over St

Traffic steering control operations over St consists of provisioning, modification, and removal of traffic steering control information.

Provisioning: Provisioning of traffic steering control information to the TSSF includes the activation of traffic steering policy, so that the traffic detected by the service data flow filter list or the application identifier can be steered in the SGi-LAN according to the information associated with the traffic steering policy identifier. The PCRF provides the UE IP address and the associated APN when provisioning of traffic steering control information to the TSSF. The TSSF uses the APN to determine the PDN.

NOTE: The APN is provided from PCRF to the TSSF for the cases when the PCEF supports multiple APNs with overlapping IP addresses. In that case, the same UE IP address can be allocated to different UEs when they access different PDNs, each APN provides access to a different PDN.

When using ADC Rules, the following applies:

– For pre-defined ADC rules in TSSF, the PCRF provides the ADC Rule identifier(s) to the TSSF;

– For dynamic ADC Rules, the PCRF provides traffic steering control information within the ADC rules to the TSSF.

Modification: The PCRF may modify traffic steering control information to change the traffic steering policy identifier(s), the precedence, the service data flow filters or application identifier.

When using ADC Rules, the PCRF may modify a dynamic ADC rule.

Removal: The PCRF may, at any time, remove traffic steering control information.

When using ADC Rules, the PCRF may remove ADC Rule(s).