BL0-100 practice question 13 of 15

What is the Unstructured Data Storage Function (UDSF)?

Answer options

A: This network function exposes 5G Core Network functionalities available to 3rd parties, so that 3rd party capabilities and events may be securely exposed by the Network Exposure Function (NEF).

B: This network function is part of data repositories in the Common Data Layer. It stores 3GPP standardized data.

C: This network function is part of data repositories in the Common Data Layer and in opposition to the UDR, it stores non-standardized – Unstructured – data. Correct answer

D: This network function stores or retrieves subscriptions, profiles, and authentication data to or from the data repositories. It offers services to the AMF, SMF, NEF and AUSF using the Service Based Interface.

Correct Answer:

C. This network function is part of data repositories in the Common Data Layer and in opposition to the UDR, it stores non-standardized – Unstructured – data.

Explanation

The Unstructured Data Storage Function (UDSF) is a stateful network function within the 5G Core's Common Data Layer. Its specific role is to store unstructured data, which is data that does not conform to the standardized data models managed by the Unified Data Repository (UDR). The UDSF allows Network Functions (NFs) to store and retrieve dynamic, non-standardized information, such as session state data or context information that is not part of a user's subscription profile. This complements the UDR, which handles structured data like subscription and policy information.

Why Incorrect

A: This describes the Network Exposure Function (NEF), which securely exposes 5G network capabilities to external third-party applications. B: This describes the Unified Data Repository (UDR), which is responsible for storing standardized, structured data like subscription profiles. D: This describes the Unified Data Management (UDM) function, which manages and provides access to subscription data stored in the UDR.

References

1. 3GPP TS 23.501 V17.7.0 (2022-12), "System architecture for the 5G System (5GS); Stage 2".

Section 5.2.1.3, "Data Storage network functions," states: "The Unstructured Data Storage Function (UDSF) is an optional function that stores unstructured data." This directly supports the correct answer (C) and refutes option B.

2. Nokia, "5G Core for Dummies, Nokia Special Edition" (2021).

Chapter 4, "Getting to Know the 5G Core Architecture," page 31, describes the Common Data Layer, differentiating between the UDR for structured data (like subscription profiles) and the UDSF for unstructured data. This confirms the distinction made in option C.

3. Nokia, "Cloud Packet Core Portfolio" official product documentation.

The section on 5G Core architecture details the roles of data layer functions, specifying UDSF for non-standardized data storage, while functions like UDM (option D) access this data via service-based interfaces. The NEF (option A) is described as the external exposure gateway.

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