Description
The Universally Unique Identifier (UUID), as standardized by 3GPP, is a 128-bit label used for the unique identification of information in network systems. Its structure and generation methods are based on IETF RFC 4122, ensuring global uniqueness with extremely high probability. Within 3GPP architectures, UUIDs are employed as persistent, opaque identifiers for a wide range of entities, including but not limited to Network Slice Instances, Network Slice Subnet Instances, Application Functions, Service Consumers, and specific service data. The 128-bit value is typically represented as a 32-character hexadecimal string, displayed in five groups separated by hyphens (e.g., 123e4567-e89b-12d3-a456-426614174000).
Architecturally, UUIDs function as key enablers in service-based interfaces (SBIs) and network slicing. In the 5G Core network, for instance, every Network Slice Instance is assigned a UUID (the S-NSSAI, while an identifier, is not a UUID; the NSI ID may be a UUID). More explicitly, UUIDs are used to identify Network Slice Templates or specific service instances within the Network Slice Management Function (NSMF) and Network Slice Subnet Management Function (NSSMF). When a service-based architecture component, like a Network Repository Function (NRF), registers or discovers a service, the service instance identifier can be a UUID. The generation of a UUID does not require a central issuing authority; it can be created locally by any system component using algorithms that incorporate unique elements like a timestamp, random numbers, and a node identifier (often a MAC address). This decentralized generation is key to its scalability.
How it works in practice involves embedding the UUID in protocol messages and data models. For example, in the 5G system, the Common API Framework (CAPIF) uses UUIDs to uniquely identify API invokers, providers, and services. In network slicing management, defined in TS 28.531, UUIDs identify management services and resources. The UUID is carried within HTTP/2 headers or JSON payloads in RESTful API calls between network functions. Its role is to provide a collision-resistant handle that can be used for referencing, correlating, and managing the lifecycle of distributed resources without ambiguity, which is essential for automation, orchestration, and multi-domain operations in complex 5G and beyond networks.
Purpose & Motivation
The UUID was adopted into 3GPP standards to solve the problem of generating globally unique identifiers in a decentralized, scalable manner for next-generation network architectures. Prior approaches often relied on hierarchical, centrally administered numbering schemes (like IP addresses or IMSI ranges) which could create bottlenecks, single points of failure, and coordination overhead. As networks evolved towards cloud-native, service-based architectures with network slicing and massive IoT, the need for a lightweight, self-generating, and statistically guaranteed unique identifier became paramount.
Historically, UUIDs were introduced from 3GPP Release 8, coinciding with the early work on System Architecture Evolution (SAE) and the Evolved Packet Core (EPC), where they found use in management interfaces. Their importance skyrocketed with the design of 5G, specifically for network slicing and service-based interfaces. UUIDs address the limitations of previous ad-hoc or operator-specific ID schemes by providing a standardized format that ensures no two independently generated IDs will conflict, even across different vendors and operators. This is critical for enabling automated orchestration, seamless service discovery, and the unambiguous management of millions of dynamic network slice instances and service endpoints in a multi-vendor, multi-domain environment.
Detected Changes Across Releases
from 3GPP Change RequestsSpecific changes extracted from the „Change history“ tables of 3GPP specifications (28 CRs across 5 releases). Complements the general historical overview above with the evidence-based evolution of this function.
Studied in Rel-8, normative work from Rel-15.
In Release 15, the UUID function was newly introduced to support the Subscription Permanent Identifier (SUPI) for privacy, specifically as the underlying mechanism for the Subscription Concealed Identifier (SUCI). This allowed for the concealment of the SUPI, which could be an IMSI or a Network Specific Identifier, using protection schemes and home network public keys. The introduction of UUIDs facilitated secure and private subscription identification within the 5G System architecture.
- External Identifier on Sh TS 23.003CR0468
- Introducing the S-NSSAI definition TS 23.003CR0485
- External identifier in 5G TS 23.003CR0498
- Changed length and mapping of 5GS Temporary Identifiers TS 23.003CR0503
- Internal-Group Identifier TS 23.003CR0520
- Presence Reporting Area Identifier (PRA ID) in 5GS TS 23.003CR0541
In Release 16, the UUID function was formally introduced and defined by referencing IETF RFC 9562 for "Universally Unique IDentifiers (UUIDs)" within the 3GPP specifications. This provided a standardized mechanism for generating globally unique identifiers, complementing other identifiers like the SUPI and SUCI. The release also clarified the use of related terms, such as URN, ensuring consistency across the system's identifier framework.
- Support for MCData emergency alert and communications MCC note: This CR introduces the abbreviation IMPU; MCC has added this in the list of abbreviations, choosing the most appropriate of the five variations appearing in other 3GPP Specs. Similarly, MCC has provided the expansions of abbreviations UUID and URN introduced, but not defined by, this CR. The newly introduced term "Group identity" has a circular definition. In §D.1.3,, "can" has been changed to "may" in newly introduced bullet points 11 c), 11 c) i), and 11 e). TS 24.282CR0126
- Network Identifier for SNPN TS 23.003CR0539
- Clarification of possible values for Home Network Public Key Identifier of SUCI TS 23.003CR0549
- Slice Differentiator (SD) in S-NSSAI TS 23.003CR0556
- Definition of Global Line Identifier TS 23.003CR0550
- Global uniqueness of NID TS 23.003CR0553
+ 2 more changes
In Release 17, the UUID function was enhanced to support new identifier types for network selection. Specifically, it introduced the **Group Identifier for Network Selection** and formally incorporated the **DNN Operator Identifier** for use within Standalone Non-Public Networks (SNPNs). These additions expanded the application of UUIDs to facilitate more flexible and specific network routing and access scenarios.
In Release 18, the UUID function was expanded to support new specific identifier types, including an NSI (Network Specific Identifier) for the SUPI, LCS (Location Services) specific identifiers, and an MPQUIC specific identifier. This release also refined identifier usage by removing Network Identifiers (NID) from the realm for IMSI-based SUCI. These updates provided a more structured and extensible framework for unique identification across various 3GPP services and protocols.
- SNPN Identifier based N3IWF FQDN TS 23.003CR0687
- NSI Identifier definition TS 23.003CR0678
- NSAC Service Area Identifier TS 23.003CR0677
- Adding LCS specific identifiers TS 23.003CR0701
- Adding MPQUIC specific identifier TS 23.003CR0702
- Removal of Network Identifiers (NID) from the realm for IMSI based SUCI. TS 23.003CR0669
In Release 19, the specification formally incorporated the modern IETF RFC 9562 for Universally Unique IDentifiers (UUIDs) as a foundational reference, replacing the older RFC 4122. This update aligns 3GPP identifiers with the current UUID standards, providing a consistent basis for defining new identifiers such as those for Non-3GPP devices, AIoT Device Permanent Identifiers, and various Location Services (LCS) connection identifiers introduced in this release.
- Non-3GPP Device Identifier TS 23.003CR0708
- Definition of AIoT Device Permanent Identifier TS 23.003CR0713
- LCS identifiers TS 23.003CR0715
- Correction of LCS User Plane Binding Identifier Definition and Reference TS 23.003CR0728
- Define LCS-UP Connection Identifier for identifying secured user-plane connections between UE and LMF TS 23.003CR0729
- Correction and Cleanup on Ambient IoT Identifiers TS 23.003CR0738
Explore further
Broader topics and technologies where UUID plays a role.
Defining Specifications
3GPP specifications that define or reference UUID, with the latest known release. Sourced from the 3GPP document catalog — see methodology.
| Specification | Title | Release |
|---|---|---|
| TS 23.003 vj50 | Numbering, addressing and identification in 3GPP | Rel-19 |
| TS 23.256 vj50 | UAS Support Architecture Enhancements | Rel-19 |
| TS 23.700 vk00 | XR Services Application Enablement Layer | Rel-20 |
| TS 24.282 vj50 | MCData Signalling Control Protocols | Rel-19 |
| TS 24.312 vj00 | ANDSF Management Objects Specification | Rel-19 |
| TS 24.334 vj00 | ProSe Protocols and Procedures | Rel-19 |
| TS 26.247 vj00 | 3GPP Progressive Download & DASH over HTTP | Rel-19 |
| TS 26.804 vj10 | 5G Media Streaming Extensions Study | Rel-19 |
| TS 29.256 vj30 | UAS-NF Stage 3 Protocol Specification | Rel-19 |
| TS 32.808 v1800 | Common User Profile Storage Framework | Rel-8 |
| TR 33.876 vi01 | Technical Report on Certificate Management | Rel-18 |