Description
The 5G Core (5GC) network is the fundamental control and connectivity framework defined by 3GPP for 5G systems, succeeding the Evolved Packet Core (EPC). It is architected as a Service-Based Architecture (SBA) where network functions (NFs) are modular software entities that expose their capabilities as services via well-defined interfaces, primarily using HTTP/2 and JSON. This cloud-native design, leveraging concepts like statelessness, microservices, and containerization, allows for flexible deployment, scaling, and lifecycle management independent of hardware. The 5GC physically separates the User Plane (UP) and Control Plane (CP), enabling distributed UP functions (UPFs) to be deployed at the network edge for low-latency services while centralizing control functions.
Key functional components include the Access and Mobility Management Function (AMF), which handles connection and mobility management; the Session Management Function (SMF), responsible for session establishment, modification, and release; and the User Plane Function (UPF), which is the anchor point for data forwarding and packet routing, inspection, and QoS enforcement. Other critical functions are the Authentication Server Function (AUSF) and Unified Data Management (UDM) for security and subscription data, the Policy Control Function (PCF) for policy governance, and the Network Repository Function (NRF) for service discovery within the SBA. The Network Exposure Function (NEF) securely exposes network capabilities to external application functions.
The 5GC operates by establishing a Protocol Data Unit (PDU) Session, which is a logical connection between the User Equipment (UE) and a specific Data Network (DN), such as the internet or an enterprise network. During initial registration, the UE interacts with the AMF and AUSF/UDM for authentication. For session establishment, the SMF, in consultation with the PCF, selects a UPF and establishes the necessary N4 interface rules for traffic handling. User data packets then flow between the UE (via the Radio Access Network) and the DN through the UPF(s), with the SMF managing the session state and the AMF handling mobility events like handovers. This architecture supports concurrent access to multiple data networks and multiple PDU sessions of different types (e.g., IPv4, IPv6, Ethernet, Unstructured).
A cornerstone capability of the 5GC is native support for Network Slicing. It allows the creation of multiple logical, end-to-end networks on a common physical infrastructure, each tailored with specific characteristics (e.g., bandwidth, latency) for different service types like enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), or massive IoT. The 5GC identifies a slice via the Single Network Slice Selection Assistance Information (S-NSSAI) and ensures a UE's PDU Session is associated with the correct slice instance, with dedicated AMF, SMF, and UPF resources as needed. Furthermore, the 5GC architecture integrates support for Edge Computing, enabling application functions to influence traffic routing (e.g., via Local Area Data Network or UPF selection) to meet stringent latency requirements.
Purpose & Motivation
The 5GC was created to address the limitations of the previous 4G Evolved Packet Core (EPC) and to meet the diverse and demanding requirements of 5G services as outlined by the IMT-2020 vision. The EPC, designed primarily for mobile broadband, was a monolithic, hardware-centric architecture with tight coupling between network functions, making it inflexible and costly to scale or innovate upon. The explosion of connected devices (IoT), the need for industrial automation with ultra-low latency, and the demand for immersive experiences like AR/VR required a more agile, efficient, and programmable core network.
Historically, each generation of mobile networks introduced a new core network (e.g., GSM's circuit-switched core, UMTS's packet-switched core, 4G's EPC). The shift to 5G presented an opportunity for a radical architectural redesign. The primary motivations were to achieve greater flexibility through software-based, cloud-native principles; to enable efficient support for a vast array of services through network slicing; and to reduce operational costs through automation and scalability. The 5GC solves these problems by decoupling software from hardware, separating the user and control planes for independent optimization, and introducing a service-based interface model that simplifies integration and enables faster deployment of new features. It is the foundational enabler for 5G to be more than just faster mobile broadband, transforming it into a platform for vertical industries and new business models.
Architecture
In the Network Map
- Mobile Network → 5GC (Core Network)
Evolution Lineage
- Evolved from: EPC (4G→5G)
- Network evolution overview →
Release Timeline
Detected Changes Across Releases
from 3GPP Change RequestsSpecific changes extracted from the „Change history“ tables of 3GPP specifications (110 CRs across 6 releases). Complements the general historical overview above with the evidence-based evolution of this function.
In Release 15, the 5G Core (5GC) introduced foundational support for interworking and migration from the EPC, including a Dual Registration mode for UEs and mechanisms for mobility from EPC to 5GC. It also specified new capabilities such as emergency call support over non-3GPP access, the introduction of Barring of Roaming, and security mechanisms for non-Service Based Architecture interfaces. Furthermore, the release defined detailed procedures for E-UTRA connected to 5GC, covering areas like NAS procedure selection, overload behavior, and key management corrections.
- OI#19 - 5GC-EPC interworking: PGW selection for 5GC UE for connectivity via untrusted access TS 23.402CR2980
- Security mechanisms for non-SBA interfaces in 5GC TS 33.501CR0374
- Selection of NAS procedures for E-UTRA connected to both EPC and 5GC TS 23.501CR0147
- TS 23.501 mobility from EPC to 5GC TS 23.501CR0024
- EPC to 5GC Migration fixes for Option 7 TS 23.501CR0084
- Dual Registration mode of operation from E-UTRA cell connecting to both EPC and 5GC TS 23.501CR0283
+ 26 more changes
In Release 16, the 5G Core introduced new capabilities for connecting a wider range of devices, including support for NB-IoT, eMTC, and wireline access via a 5G-RG/FN-RG. It also added new procedures such as Suspend-Resume for the core network and enhanced location services with a commercial and deferred 5GC-MT-LR operation. Furthermore, the release specified architectural solutions for Integrated Access and Backhaul (IAB) and improvements for non-3GPP access, including corrections for devices that do not support NAS over WLAN.
- Restriction of use of Enhanced Coverage in 5GC TS 23.501CR0820
- Access to 5GC from UEs not supporting NAS over non-3GPP access TS 23.501CR1128
- Handling of IAB-indication to 5GC TS 23.501CR1901
- AMF Location Service Operations for a Commercial and Deferred 5GC-MT-LR TS 29.518CR0262
- Solution for IAB Architecture - 5GC TS 33.501CR0782
- Introduction of NBIOT dedicated CP functions when connected to 5GC TS 38.410CR0018
+ 22 more changes
In Release 17, the 5G Core introduced several key enhancements, including support for Multi-Access PDU sessions combining E-UTRAN/EPC and non-3GPP access, and architecture updates for dynamically changing policies. It also added new capabilities such as 5GC-assisted cell selection for network slices, differentiation for RedCap UEs, and authorization for Edge Application Server discovery. Furthermore, the release extended features like UPIP support for all NG-RAN options and improved interworking with EPC for functions like Lawful Interception and LTE-M indication during mobility.
- MA PDU sessions with connectivity over E-UTRAN/EPC and non-3GPP access to 5GC TS 23.501CR2527
- 5G system architecture updates to support Dynamically Changing Policies in the 5GC TS 23.501CR2560
- Support of 5GC assisted cell selection to access network slice TS 23.501CR2719
- 5GS Connection release support for 5GC/NR TS 23.501CR3088
- Support RedCap UEs differentiation in 5GC TS 23.501CR3155
- UE authorization for 5GC assisted EAS discovery TS 29.503CR0755
+ 9 more changes
In Release 18, key 5GC enhancements included the introduction of spending limits for Access Management and UE policies, support for the 5GC-MT-LR procedure involving a Mobile Base Station Relay, and enabling UE-level measurements collection. It also expanded support for non-3GPP access, specifying service restrictions for AUN3 devices and authentication for NSWO via W-5GAN and CH with an AAA Server, while refining support for PIN and MPS over WLAN access.
- Discovery and Selection of the NWDAF Supporting Federated Learning in 5GC TS 23.501CR3772
- MPS when access to 5GC is WLAN TS 23.501CR3745
- PIN support in 5GC TS 23.501CR3854
- 23.501 - Spending Limits for AM and UE Policies in the 5GC TS 23.501CR3886
- 23.501 - Spending Limits for AM and UE Policies in the 5GC TS 23.501CR4666
- Support of 5GC-MT-LR procedure involving Mobile Base Station Relay TS 29.515CR0120
+ 16 more changes
In Release 19, the 5G Core Network introduced significant enhancements focused on network resilience and charging. Key additions include new procedures for the detection and PCRF/PCF-based restoration of EPC/5GC Network Function failures, as well as specific health check and recovery mechanisms for IMS terminating calls. The release also extended charging support and introduced CHF discovery based on CHF GroupId, alongside new capabilities for QoS monitoring configuration and transfer within the 5GC.
- Add a new clause of detection of EPC/5GC NF failures and IMS restoration procedures TS 23.380CR0127
- Add the PCRF/PCF-based restoration solution for EPC/5GC NF failure TS 23.380CR0128
- EPC/5GC health check and recovery upon IMS Terminating Call TS 23.380CR0134
- CHF discovery support based on CHF GroupId in 5GC TS 29.503CR1409
- Extending Charging support in 5GC TS 29.507CR0335
- 5GC Network Functions health check and failure recovery TS 29.513CR0617
+ 6 more changes
In Release 20, the primary update for the 5GC function was the enhancement of its management specifications. This involved adding missing foundational concepts and background information required for the management of both the 5G Core network and the NG-RAN. The change aimed to provide a more complete and robust framework for network management operations.
- Rel-20 CR TS 28.540 add missing concepts and backgrouds of management of NG-RAN and 5GC TS 28.540CR0055
Explore further
Broader topics and technologies where 5GC plays a role.
Defining Specifications
3GPP specifications that define or reference 5GC, with the latest known release. Sourced from the 3GPP document catalog — see methodology.
| Specification | Title | Release |
|---|---|---|
| TR 21.905 vj00 | 3GPP Technical Terms and Definitions | Rel-19 |
| TS 22.830 vg10 | Business Role Models for Network Slicing | Rel-16 |
| TS 23.292 vj00 | IMS Centralized Services (ICS) Architecture | Rel-19 |
| TS 23.380 vj10 | IMS Restoration Procedures | Rel-19 |
| TS 23.402 vj00 | EPC for Non-3GPP Access (PMIP) | Rel-19 |
| TS 23.501 vk00 | 5G System Architecture Stage 2 | Rel-20 |
| TS 23.700 vk00 | XR Services Application Enablement Layer | Rel-20 |
| TR 23.732 vg00 | User Data Interworking, Coexistence, Migration Study | Rel-16 |
| TR 23.745 vh00 | Study on App Layer Support for Factories of the Future in 5G | Rel-17 |
| TR 23.758 vh00 | Study on Edge Application Architecture | Rel-17 |
| TR 23.783 vi00 | Technical Report on Mission Critical Services over 5GS | Rel-18 |
| TR 23.794 vh00 | Study on enhanced IMS to 5GC integration | Rel-17 |
| TR 23.973 vj00 | Separate HSS/UDM Deployment Scenarios & Solutions | Rel-19 |
| TS 24.229 vj50 | IMS call control protocol based on SIP and SDP | Rel-19 |
| TS 26.114 vj10 | IMS Multimedia Telephony Media Handling | Rel-19 |
| TS 26.132 vj00 | Terminal Acoustic Test Methods | Rel-19 |
| TS 26.501 vj30 | 5G Media Streaming (5GMS) Architecture | Rel-19 |
| TS 26.510 vj10 | Media Delivery APIs for 5GMS and RTC Systems | Rel-19 |
| TR 26.919 vj00 | Study on 5G Conversational Media Handling | Rel-19 |
| TR 26.942 vj00 | Study on Media Energy Consumption Exposure & Evaluation | Rel-19 |
| TS 28.531 vk00 | Management and Orchestration | Rel-20 |
| TS 28.540 vk10 | 5G Network Resource Model (NRM) Management | Rel-20 |
| TS 28.802 vf00 | Management Study for 5G Network Architecture | Rel-15 |
| TR 28.808 vh00 | 5G satellite integration management study | Rel-17 |
| TR 28.841 vi01 | Technical Report on IoT NTN Enhancements | Rel-18 |
| TS 28.874 vj10 | Study on Management Aspects of NTN Phase 2 | Rel-19 |
| TS 28.879 vj10 | OAM for Service Management Exposure Study | Rel-19 |
| TS 29.168 vj00 | SBc-AP Protocol Specification | Rel-19 |
| TS 29.274 vj50 | GTPv2-C Control Plane Protocol Specification | Rel-19 |
| TS 29.501 vj40 | 5GC SBI API Design Principles & Guidelines | Rel-19 |
| TS 29.503 vj50 | UDM Service Based Interface Stage 3 | Rel-19 |
| TS 29.505 vj50 | UDR Service for Subscription Data Usage | Rel-19 |
| TS 29.507 vj40 | 5G Access & Mobility Policy Control Service | Rel-19 |
| TS 29.510 vj50 | NRF Service Based Interface Protocol | Rel-19 |
| TS 29.513 vj40 | 5G PCC Signalling Flows & QoS Mapping | Rel-19 |
| TS 29.515 vj50 | Ngmlc Service Based Interface Protocol | Rel-19 |
| TS 29.518 vj50 | AMF Service Based Interface Protocol | Rel-19 |
| TS 29.524 vj00 | 5G Cause Code Mapping Specification | Rel-19 |
| TS 29.536 vj30 | NSACF Service Based Interface Protocol | Rel-19 |
| TS 29.540 vj40 | Nsmsf Service Based Interface Stage 3 | Rel-19 |
| TS 29.542 vj30 | SMF NIDD Service Based Interface Stage 3 | Rel-19 |
| TS 29.562 vj40 | HSS Services for IMS & GBA Interworking | Rel-19 |
| TS 29.563 vj30 | TS 29563: Nhss services for HSS-UDM interworking | Rel-19 |
| TS 29.571 vj50 | Common Data Types for 5G Service Based Interfaces | Rel-19 |
| TS 29.598 vj40 | UDSF Service Based Interface Stage 3 Protocol | Rel-19 |
| TS 29.866 vj00 | IMS Disaster Prevention & Restoration Enhancement | Rel-19 |
| TS 29.890 vg00 | CT3 5G System Technical Report | Rel-16 |
| TS 32.240 vj40 | Charging Management Architecture & Principles | Rel-19 |
| TS 32.255 vk10 | Telecom Management; Charging for 5G Data Connectivity | Rel-20 |
| TS 32.256 vj40 | 5G Connection & Mobility Charging Spec | Rel-19 |
| TS 32.279 vj00 | 5G MBS Session Converged Charging | Rel-19 |
| TS 32.290 vj50 | 5G Charging for Service Based Interface | Rel-19 |
| TS 32.299 vj00 | Diameter Charging Applications for 3GPP | Rel-19 |
| TS 32.404 vj00 | Performance Management Definitions & Template | Rel-19 |
| TS 32.432 vj00 | Performance measurement file format definition | Rel-19 |
| TR 32.972 vj00 | Energy Efficiency Study for 5G Networks | Rel-19 |
| TS 33.127 vj50 | Lawful Interception Architecture and Functions | Rel-19 |
| TS 33.501 vk00 | 5G Security Architecture and Procedures | Rel-20 |
| TS 33.511 vk00 | Security Assurance Specification (SCAS) for gNB | Rel-20 |
| TS 33.536 vj00 | 5G V2X Security for NR PC5 | Rel-19 |
| TS 33.545 vj20 | Security for NR Femto Subsystem | Rel-19 |
| TS 33.814 vg01 | Security aspects of enhanced Location Services (eLCS) | Rel-16 |
| TS 33.835 vg10 | Study on authentication and key management for apps | Rel-16 |
| TS 33.836 vg10 | Security Study for Advanced V2X Services | Rel-16 |
| TR 33.847 vh10 | 5G Proximity Services Security Study | Rel-17 |
| TS 36.300 vj00 | E-UTRAN Radio Interface Protocol Architecture Overview | Rel-19 |
| TS 37.473 vj00 | W1 Application Protocol (W1AP) Specification | Rel-19 |
| TS 37.483 vj10 | E1 Application Protocol (E1AP) | Rel-19 |
| TR 37.985 vj00 | Overview of V2X features in LTE and NR | Rel-19 |
| TS 38.300 vj00 | NG-RAN Overall Description | Rel-19 |
| TS 38.305 vj00 | NG-RAN UE Positioning Stage 2 | Rel-19 |
| TS 38.331 vj00 | NR Radio Resource Control (RRC) Protocol Specification | Rel-19 |
| TS 38.401 vj10 | NG-RAN Architecture Specification | Rel-19 |
| TS 38.410 vj10 | NG Interface Introduction for NG-RAN to 5GC | Rel-19 |
| TS 38.412 vj00 | NG Signalling Transport | Rel-19 |
| TS 38.413 vj10 | NG Application Protocol (NGAP) | Rel-19 |
| TS 38.414 vj00 | NG Interface User Plane Protocol | Rel-19 |
| TS 38.463 vj00 | E1 Application Protocol (E1AP) | Rel-19 |
| TS 38.473 vj10 | 5G F1 Application Protocol (F1AP) | Rel-19 |
| TS 38.508 vj11 | 5G NR UE Radio Transmission & Reception | Rel-19 |
| TS 38.523 vj20 | 5G NR UE Conformance Testing: Idle/Inactive | Rel-19 |
