warding, routing, marking, quality of service (QoS), inspection, and SO on. Enforce policies received from the Policy Control Function (PCF) (via the SMF). Send traffic usage reporting to the SMF for charging. Act as the anchor point for intra-/inter-radio access technology (RAT) mobility. Connect to external networks (N6) or other UPFs. 5.3.4 Data Storage Architecture The Unified Data Repository (UDR) is a common database for all kinds of standardized data structures including Subscription Data, Policy Data, Structured Data for exposure, and Application Data. Three different network functions can access the UDR to read, update, delete, and subscribe to notifications of data changes. UDM hides application logic from the UDR. UDM takes care of, for example, gen- eration of authentication credentials, identity handling (both user and subscription), information storage about serving entities like the AMF and SMF, and SMS delivery support. In addition to standardized structure data, the 5G architecture enables any net- work function to store unstructured in the Unstructured Data Storage Function (UDSF). This capability enables a network function to store all UE-related data in the UDSF, and thus the network function can become stateless. In Release 15, this is capability is defined for the AMF. 5.3.5 Policy Control Function The PCF governs network behavior by applying a unified policy framework. This is enabled with the following primary capabilities: Creation of both SM and access management policy association Provision and deletion of policy and charging management decisions 5 5G Architecture Provision and deletion of access and mobility management decisions Delivery of UE access selection and PDU session selection policies to the UE via the Ability to utilize policy-control-related subscription information and application- specific information stored in the UDR Ability to obtain spending limit reports from the Charging Function Interactions with the NEF (Network Exposure Function), for example, to obtain Applicati