5G Core Network Architecture


5G Core Network Architecture

The 5G Core network architecture consists of several sub-layers. Session Management Function (SMF) transports IP data traffic between UEs and external networks, User Plane Function (UPF) carries IP traffic between UE and 5G core network, Authentication Server Function (AUSF) authenticates UE and 5G core services, and Unified Data Management Function (UDMF) provides policy control framework and subscription information.

Session Management Function (SMF)

A Session Management Function (SMF) is a key component of the 5G core network. It provides UEs with a QoS profile and binds PCC rules to the QoS Flow. This allows UEs to map DL and UL data to the appropriate QoS Flow.

An SMF is a protocol that enables applications and services to communicate with each other. SMFs may also include policy-related functionalities. These functions include gating control, policy-related functions, and a unified packet flow protocol (UPF).

SMFs support mobility and access. In addition, they support N2-based handovers, multiple PDN connections, and network-initiated messages. Several key functions of SMFs are described in detail in the Ultra Cloud Core SMF Cluster Deployment Operations Guide.

A 5G SMF must be Cloud-native, dynamically deployable, and flexible. It must support asynchronous call flows and state management, and it must be able to scale on demand. It must also support high-availability control components. In addition, it must support both short-lived and long-lived state maintenance. In addition, the SMF must be highly scalable and adopt design patterns developed for massively scalable web applications.

In 5G, the Session Management Function (SMF) plays an important role in managing user sessions and connecting UEs to Data Networks. In addition, the SMF controls the User Plane and allocates IP addresses for IP PDU sessions. The SMF communicates with the UE through the Access Management Function (AMF), which relays session-related messages.

The SMF is an essential element of the Service-Based Architecture and maintains PDU session synchronization in the 5G Core network. It also receives PCC rules from PCF and converts them into SDF Templates, QoS Profiles, and QoS Rules.

Authentication Server Function (AUSF)

The Authentication Server Function (AUSF) of 5G Core network is a central part of 5G authentication. The purpose of the AUSF is to authenticate the UE before it can connect to the network. When a UE attempts to connect to the network, the AUSF receives an authentication request and verifies the UE’s authorization.

The AUSF performs two-factor authentication. The UE first sends a Challenge Response message to the SEAF, which forwards it to the AUSF. The SEAF then computes a response, HRES*, from the RES* received. It then compares the HRES* to the HXRES* and determines whether the authentication was successful. If the two parties have the same secret key, the UE can proceed with the authentication.

The AUSF supports both EAP-TLS and non-3GPP authentication methods. Its mission is to provide secure and trusted access to 5G networks and to support various use cases. In addition, it is compatible with non-3GPP access networks and Wi-Fi networks.

The AUSF can perform authentication and manage user profiles. It is responsible for ensuring that the UE can access the network and access the services that it requires. In addition to performing these functions, the AUSF can also handle authentication requests from untrusted users.

Authentication Server Function (AUSF) is a key component in 5G Core network. It facilitates secure access by facilitating the exchange of secure data across 5GCN and WLANs. Moreover, it is responsible for managing the two CM states for each access.

AUSF can be implemented in both the SMF and the DN-AAA servers in 5G Core network. In the older generation systems, mobile operators conduct access control without support of the DN, which makes it easy for malicious UEs to instigate the authentication service provided by the DN. However, the 5G system allows mobile operators to delegate this authentication task to a third-party hosting the DN.

Infrastructure-agnostic design

The 5G Core network must be flexible enough to support different data profiles. As a result, it needs to support new techniques such as Network Function Virtualization and Software Defined Networking. It should be able to support different access types, thereby reducing reliance on a single underlying infrastructure. Moreover, it must be able to operate efficiently.

The 5G policy control architecture will determine the resources that connected devices will need. It will enable network slicing to scale multiple applications and services without slowing down the overall network. It also simplifies network operations and prevents errors from affecting productivity. In addition, the infrastructure-agnostic design of the 5G core network will allow deployment anywhere – even on edge clouds. Its open APIs will allow developers to customize the network for any type of application or service.

The 5G Core network will be the hub of 5G mobile networks. It will establish secure and reliable connectivity to the 5G network, allowing mobile users to access the network’s services. It is also the heart of the network transformation and must be flexible, programmable and distributed.

The 5G Core network is a software-based architecture and is built on cloud native technology. It leverages microservices, orchestration, CI/CD pipelines, APIs, and service meshes to create the core network functions that are needed for 5G mobile networks.

This approach requires the use of infrastructure-agnostic designs to avoid reliance on proprietary technology. It also requires a flexible signalling architecture, and CSPs must be able to fine tune operations and fix problems when they arise.

Reliability and quality requirements

5G network infrastructure must support both flexibility and reliability. Reliability and quality requirements are particularly important in the cloud-native environment. As network complexity increases and technologies evolve, the architecture must be flexible to accommodate it. This will help service providers and operators realize their business objectives with reduced costs and increased revenues. Moreover, it will help them realize a more scalable and resilient network.

To meet these requirements, service providers must test their 5G systems with high traffic load and volume. For instance, they should ensure that the system can support Busy Hour Calls (BHCA), which exceed the peak transaction per second (TPS) of the system. Furthermore, they should evaluate and benchmark the system to find out its Key Performance Indicators (KPIs). This can be done by using open-source tools.

The 5G network must support mMTC (massive machine-type communications). This type of service is best suited for the internet of things, as it can serve billions of devices and a density of one million per square kilometer. It should also have advanced reliability parameters and end-to-end latency. The block error ratio is expected to be less than one millisecond, while jitter will be reduced to 10 to 100 microseconds.

5G networks must also support URLLC. This technology allows for one-millisecond latency and 5-9s network reliability, paving the way for new technologies and applications. Besides enabling smartphones, URLLC supports V2V communication, intelligent transport systems, and remote healthcare. It is faster than 4G, with zero delays and a continuous stream of data.

Moreover, the new technology can enable new features, business models, and diverse services. However, this also presents new challenges for the telecom industry. Increasing data traffic will require a network that supports machine-to-machine communication, node-to-node communication, and backward compatibility. Further, it will have to support a rapidly growing number of devices.


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