Section: 5.17.1.2 User Plane management to support interworking with EPS
Content: In order to support the interworking with EPC, the SMF+PGW-C provides information over N4 to the UPF+PGW-U related to the handling of traffic over S5-U. Functionality defined in TS 23.503[ Policy and charging control framework for the 5G System (5GS); Stage 2 ]  [45] for traffic steering control on SGi-LAN/N6 can be activated in UPF+PGW-U under consideration of whether the UE is connected to EPC or 5GC. When the UE is connected to EPC and establishes/releases PDN connections, the following differences apply to N4 compared to when the UE is connected to 5GC: - The CN Tunnel Info is allocated for each EPS Bearer. - In addition to the Service Data Flow related information, the SMF+PGW-C shall be able to provide the GBR and MBR values for each GBR bearer of the PDN connection to the UPF+PGW-U. If the UE does not have preconfigured rules for associating an application to a PDN connection (i.e. the UE does not have rules in UE local configuration and is not provisioned with ANDSF rules), the UE should use a matching URSP rule as defined in TS 23.503[ Policy and charging control framework for the 5G System (5GS); Stage 2 ]  [45], if available, to derive the parameters, e.g. APN, for the PDN connection establishment and associating an application to the PDN connection. NOTE: The mapping between the parameters in the URSP rules and the parameters used for PDN connection establishment is defined in TS 24.526[ User Equipment (UE) policies for 5G System (5GS); Stage 3 ]  [110].