Section: 4.11.0a.2a Interaction with PCC for URSP delivery via EPS 4.11.0a.2a.0 General
Content: This clause captures the enhancement to the interaction with PCC to support URSP delivery via EPS. To Support URSP provisioning in EPS, the SMF+PGW-C receives the Indication of URSP Provisioning Support from the UE as defined in TS 23.501[ System architecture for the 5G System (5GS) ]  [2]. If the SMF+PGW-C also supports URSP Provisioning Support in EPS and ePCO, it selects a PCF which also supports URSP Provisioning in EPS to establish the SM Policy Association based on the received Indication of URSP Provisioning Support in EPS PCO and local configuration. The SMF+PGW-C then provides the "Indication of URSP Provisioning Support in EPS" in the ePCO to the UE. When the SMF+PGW-C receives the UE Policy Container ePCO in Bearer Resource Command during UE requested bearer resource modification procedure, it forwards transparently the UE Policy Container to PCF for the PDU Session in the Npcf_SMPolicyControl_Update Request including indication that "UE Policy Container received" PCRT was met. When the PCF for Session Management receives UE Policy Container from PCF for the UE, it forwards the UE Policy Container to SMF+PGW-C in Npcf_SMPolicyControl_UpdateNotify Request. The PCF for the PDU Session retrieves the PCRTs for UE Policy from PCF for the UE and subscribe to the applicable PCRTs in EPC to SMF+PGW-C. When URSP Provisioning is supported in EPS, the PCF for the PDU Session may establish the UE Policy Association with PCF for the UE: - When the first UE Policy Container is received from the UE for an SM Policy association. - During 5GS to EPS mobility with N26 when the SMF+PGW-C notifies the PCF for the PDU Session about a RAT-Type change via Npcf_SMPolicyControl_Update. The PCF for the UE triggers the re-evaluation of applicable URSPs in the cases as described in clause 6.1.2.2.3 of TS 23.503[ Policy and charging control framework for the 5G System (5GS); Stage 2 ]  [20] and determines whether an update of URSP is needed for the UE. The PCF for the UE generates the URSP and sends it to the PCF for the PDU Session in the UE Policy Container via Npcf_UEPolicyControl_UpdateNotify Request. The procedures for the UE Policy association defined in clauses 4.16.11, 4.16.12 and 4.16.13 apply in EPS with the main differences below: - AMF is replaced by the PCF for the PDU Session. - Delivery of UE Policy Containers from the PCF for the UE to the PCF for the PDU Session is done via Npcf_UEPolicyControl service instead of via UE Configuration Update procedure. - Delivery of UE Policy Containers from the SMF+PGW-C to the UE is done via PDN GW initiated bearer modification without QoS update procedure as specified in clause 4.11.0a.2a.10. URSP delivery via EPS is also supported in roaming scenarios, both for a PDN connection established in Home Routed and for a PDN connection established in LBO. NOTE: If the PCF for the PDU Session is the same as the PCF for the UE, the interactions between them are internal to the PCF.