Core Network in 2026: Evolution, Architecture & Best Practices

Evolution of Mobile Core Networks

Telecommunications core networks have progressed through several generations, each bringing enhanced capabilities and efficiencies. 

2G-3G

The second and third generations of mobile networks introduced significant advances in mobile communications. 2G networks were built on circuit-switched architecture designed primarily for voice services, while 3G added packet-switched capabilities to support data services such as mobile internet and multimedia messaging. 

Standards developed under 3GPP provided a unified framework for global deployment, enabling operators to offer improved mobility, connectivity, and subscriber management as mobile use expanded beyond voice to include email, browsing, and early mobile apps.

4G

The transition to 4G LTE marked a fundamental shift to fully packet-based core networks, eliminating legacy circuit-switched systems. This architecture enabled higher data rates and lower latency, allowing operators to deliver rich media services such as high-definition video streaming and real-time gaming. 

The 4G core also laid the groundwork for mobile broadband as a mainstream utility, integrating functions like policy management and subscriber data handling within a more scalable, efficient design to accommodate explosive growth in mobile data consumption.

5G

The evolution to 5G introduces a completely redesigned core network architecture known as the 5G core (5GC). It supports advanced capabilities such as network slicing, service-based architecture (SBA), and tight integration with cloud and edge computing resources. 

These innovations enable ultra-reliable low-latency communications (URLLC), massive machine-type communications for IoT, and enhanced mobile broadband (eMBB). The 5G core is also cloud-native, supporting automation and dynamic scalability to handle diverse use cases and future technologies like 5G Advanced and 6G.

5.5G

The evolution toward 5.5G, also referred to as 5G-Advanced, standardized through 3GPP Release 18, extends the 5G system with new capabilities across radio, core, and service layers. It is better described as an evolution of 5G than as a new standalone “5.5G core” architecture.

In 5.5G, the core network becomes more AI-driven and automated, enabling real-time optimization of network resources, predictive maintenance, and more efficient traffic management. It enhances existing capabilities such as network slicing and edge integration, allowing operators to deliver highly customized and reliable services for advanced use cases like extended reality (XR), autonomous systems, and large-scale IoT deployments.

This phase also focuses on higher data rates, lower latency, and massive connectivity, supporting up to tens of gigabits per second and significantly increasing the number of connected devices. Improvements in spectral efficiency and energy consumption make networks more scalable and sustainable.

Additionally, 5.5G introduces new communication paradigms—such as enhanced uplink performance, real-time broadband communication, and integrated sensing capabilities—expanding the role of the core network beyond connectivity into intelligent service orchestration.

Learn more in our detailed guide to core network 5G

Mobile Core Network Market and Trends

Telecommunications core networks have progressed through several generations, each bringing enhanced capabilities and efficiencies. 

2G-3G

The second and third generations of mobile networks introduced significant advances in mobile communications. 2G networks were built on circuit-switched architecture designed primarily for voice services, while 3G added packet-switched capabilities to support data services such as mobile internet and multimedia messaging. 

Standards developed under 3GPP provided a unified framework for global deployment, enabling operators to offer improved mobility, connectivity, and subscriber management as mobile use expanded beyond voice to include email, browsing, and early mobile apps.

4G

The transition to 4G LTE marked a fundamental shift to fully packet-based core networks, eliminating legacy circuit-switched systems. This architecture enabled higher data rates and lower latency, allowing operators to deliver rich media services such as high-definition video streaming and real-time gaming. 

The 4G core also laid the groundwork for mobile broadband as a mainstream utility, integrating functions like policy management and subscriber data handling within a more scalable, efficient design to accommodate explosive growth in mobile data consumption.

5G

The evolution to 5G introduces a completely redesigned core network architecture known as the 5G core (5GC). It supports advanced capabilities such as network slicing, service-based architecture (SBA), and tight integration with cloud and edge computing resources. 

These innovations enable ultra-reliable low-latency communications (URLLC), massive machine-type communications for IoT, and enhanced mobile broadband (eMBB). The 5G core is also cloud-native, supporting automation and dynamic scalability to handle diverse use cases and future technologies like 5G Advanced and 6G.

5.5G

The evolution toward 5.5G, also referred to as 5G-Advanced, standardized through 3GPP Release 18, extends the 5G system with new capabilities across radio, core, and service layers. It is better described as an evolution of 5G than as a new standalone “5.5G core” architecture.

In 5.5G, the core network becomes more AI-driven and automated, enabling real-time optimization of network resources, predictive maintenance, and more efficient traffic management. It enhances existing capabilities such as network slicing and edge integration, allowing operators to deliver highly customized and reliable services for advanced use cases like extended reality (XR), autonomous systems, and large-scale IoT deployments.

This phase also focuses on higher data rates, lower latency, and massive connectivity, supporting up to tens of gigabits per second and significantly increasing the number of connected devices. Improvements in spectral efficiency and energy consumption make networks more scalable and sustainable.

Additionally, 5.5G introduces new communication paradigms—such as enhanced uplink performance, real-time broadband communication, and integrated sensing capabilities—expanding the role of the core network beyond connectivity into intelligent service orchestration.

Learn more in our detailed guide to core network 5G

5G Core Network Architecture Concepts

Market Size And Growth Forecast

According to recent market research, the mobile core network market is valued at USD 37.61 billion. It is projected to grow to USD 52.19 billion by 2031, at a CAGR of 5.61%.

This steady growth follows the peak phase of 5G deployments. Operators are now focusing on cloud-native migration, AI-driven automation, and cost-efficient capacity expansion rather than large-scale greenfield rollouts.

Key Growth Drivers

Surge In Mobile Data Consumption
According to estimates published by Ericsson, global mobile traffic has reached 237 exabytes per month, growing at 46% annually. Operators are shifting to elastic scaling models to handle traffic variability. Uplink-heavy applications, including AI-generated video, are increasing demand for advanced session management, user plane anchoring, and real-time policy control.

5G Stand-Alone Core Rollouts
There are 95 5G SA networks worldwide. SA cores enable network slicing, Voice-over-NR, URLLC, and API-based monetization. Enterprise and IoT use cases are making SA capabilities essential, sustaining long-term equipment and software demand.

Cloud-Native And Network Virtualization
Operators use Kubernetes-based cloud-native functions to improve resource use, automate lifecycle management, and cut manual operating effort. The size of those gains depends on the network design and operating model .

Massive IoT Expansion
Cellular IoT connections are expected to reach 7.5 billion by 2033. Integration of NB-IoT and LTE-M into 5G cores supports low-power devices with long battery life. Growth requires scalable subscriber data platforms capable of handling trillions of policy decisions daily and supporting granular billing models.

Spectrum Auctions
Recent spectrum auctions in India, the US, and Canada are accelerating infrastructure upgrades. These regulatory actions create short-term demand for core modernization.

Key Market Segments

By Product Category
Session Border Controllers (SBCs) held 38.76% market share in 2025. Cloud-native SBCs are projected to grow at a 9.05% CAGR through 2031, driven by voice-over-5G and enterprise communications services.

By Core Controller
The Mobility Management Entity (MME) accounted for 30.15% of market share in 2025. However, the Session Management Function (SMF) is the fastest-growing segment, with a projected CAGR of 10.45%, reflecting the transition to 5G SA architectures.

By Subscriber Data Platform
Home Subscriber Server (HSS) held 58.05% of the market in 2025. Unified Data Management (UDM) is expanding at a 12.17% CAGR, driven by demand for unified subscriber views and real-time policy control.

By Deployment Model
Virtualized Network Functions (VNFs) captured 59.05% of revenue in 2025. Cloud-Native Functions (CNFs) are growing at a 7.98% CAGR as operators containerize network workloads and adopt DevSecOps models.

Core Network Components

Architectural Models

The 5G core network introduces a service-based architecture (SBA), a shift from traditional, rigid network designs. SBA uses modular network functions that interact through standard APIs, promoting interoperability and flexibility. These microservice-based components are deployed in a cloud-native environment, which enables automation, efficient scaling, and rapid innovation.

Operators can now deploy the 5G core in private, public, or hybrid cloud environments. This deployment flexibility supports diverse scenarios—from private industrial networks to national mobile networks—and enables edge computing for latency-sensitive applications. By decoupling software from hardware, SBA reduces operational complexity and supports on-demand service delivery.

Control Plane Functions

The control plane in the 5G core handles essential signaling tasks that govern the behavior of the network and devices. This includes subscriber authentication, mobility management, session management, and policy control. Key functions like the Access and Mobility Management Function (AMF) and the Session Management Function (SMF) are deployed as microservices and communicate via APIs in SBA.

Automation is central to the control plane. With 5G, resources are allocated dynamically based on demand, reducing manual intervention and minimizing configuration errors. Additionally, exposure functions like the Network Exposure Function (NEF) enable third-party developers to access network capabilities through secure, standardized APIs.

User Plane Function

The User Plane Function (UPF) is responsible for routing and forwarding user data packets within the 5G network. It serves as the interface between the core and external networks, such as the internet or enterprise data centers. In modern deployments, UPFs can be placed closer to end users using edge cloud infrastructure, reducing latency and enhancing performance for real-time applications.

Edge-deployed UPFs are essential for supporting Industry 4.0 use cases like autonomous vehicles and predictive maintenance. These use cases require low-latency, high-throughput connections, which the distributed nature of UPFs in a 5G architecture can effectively support.

Voice continuity in 5G: VoLTE in NSA and VoNR in SA 

Voice services in 5G networks are delivered through two different models depending on the network deployment type: non-standalone (NSA) and standalone (SA). In NSA deployments, 5G radio access is paired with the existing 4G LTE core network—known as the Evolved Packet Core (EPC)—which continues to handle voice services through Voice over LTE (VoLTE). VoLTE relies on the interworking of EPC and the IP Multimedia Subsystem (IMS) to deliver voice calls and SMS as packet-switched data.

While VoNR represents the long-term direction for 5G voice, VoLTE will remain relevant as 4G and 5G networks are expected to coexist for years. Operators can deploy hybrid solutions, leveraging VoLTE in NSA deployments and VoNR in SA scenarios, depending on coverage, infrastructure readiness, and device compatibility.

PDN Gateway (PGW) vs. Packet Gateway

In 4G LTE networks, the PDN Gateway (PGW) served as the interface between the mobile network and external packet data networks. In the transition to 5G, the PGW’s functions are largely replaced or absorbed by the UPF in the new architecture. While existing 4G operators can initially deploy 5G in non-standalone (NSA) mode—leveraging the existing PGW—the move to standalone (SA) 5G involves migrating to UPF-based architecture.

This evolution allows operators to gradually transform their core network while still offering enhanced broadband services. As the shift toward full 5G SA continues, the PGW becomes less central, giving way to the more agile and scalable UPF.

Learn more in our detailed guide to 5G core network architecture

Core Network Interfaces and Protocols

Virtualized Network Functions (VNFs)

Virtualized network functions are software-based implementations of network services that run on shared compute infrastructure instead of dedicated appliances. In modern mobile cores, VNFs are part of the shift away from fixed-function hardware, while cloud-native functions, or CNFs, take that model further by packaging network functions as containerized microservices.

Containerized microservices are more accurately described as CNFs rather than VNFs. Those functions can be deployed across private, public, or hybrid cloud environments when the operator’s architecture supports that model. This enables operators to reduce time-to-market, optimize costs with OpEx-based models, and dynamically allocate resources based on real-time demand. These virtual functions are also important in network slicing, where they can be isolated and customized per slice to meet specific performance and security requirements.

Physical Network Functions (PNFs)

Physical network functions refer to traditional, hardware-bound network elements that still play a role in modern telecommunications infrastructure. Although 5G emphasizes virtualization and cloud-native design, PNFs may still be used in certain scenarios for performance, legacy compatibility, or regulatory reasons.

PNFs are typically deployed in centralized data centers and offer fixed capacities. While they lack the flexibility and scalability of VNFs, they may be preferred in networks where deterministic performance or hardware acceleration is required. For some service providers transitioning gradually from 4G to 5G, PNFs continue to support legacy interfaces and services until the network is fully virtualized.

Edge Devices

Edge devices in the context of the core network are nodes deployed closer to end users or devices to enable real-time data processing and reduce latency. They play a critical role in supporting use cases like autonomous vehicles, industrial automation, and smart cities.

5G edge deployments often include UPFs and other user-plane functions that are relocated from centralized data centers to regional or on-premises edge sites. This distribution supports Industry 4.0 applications by bringing compute and storage closer to the data source. Edge devices also allow for compliance with data localization laws by ensuring that user data is processed within national borders. Their deployment is made possible by the platform-agnostic nature of cloud-native 5G cores, which can run on Kubernetes, OpenShift, or public cloud infrastructure like AWS or Google Cloud.

Network Slicing in 5G Core

In legacy networks, core communication relied on protocols like GTP (GPRS tunneling protocol), Diameter, and SCTP. While some of these still exist in interworking scenarios, 5G’s native protocol stack is designed to simplify operations and improve interoperability across distributed environments and hybrid infrastructures.

The 5G core network relies on a service-based interface model in which core functions communicate through standardized APIs. This marks a shift from the legacy point-to-point interfaces used in earlier mobile generations. In the service-based architecture (SBA), each network function exposes its capabilities as services that other functions can access through RESTful APIs over HTTP/2, enabling flexible, scalable, and modular interaction.

Key interfaces include:

• N1/N2/N3 for communication between user equipment, the radio access network (RAN), and the core.
• N6 between the User Plane Function (UPF) and external data networks.
• N8/N10/N11, among others, for internal signaling between control functions like AMF (Access and Mobility Management Function), SMF (Session Management Function), and UDM (Unified Data Management).

Within the 5G service-based interface, HTTP/2 and JSON are used for communication between many core functions. They do not replace every telecom-specific protocol across the network, because interfaces such as N2 and N3 still rely on protocols such as NGAP and GTP-U. This API-driven approach also underpins the Network Exposure Function (NEF), which allows external applications to interface with the core network through securely exposed APIs.

Challenges in Core Network Implementation and Management

Network slicing is a capability of the 5G core network that enables operators to partition a single physical network into multiple virtual networks—or “slices”—each optimized for a specific use case, customer, or service requirement. This is made possible by the cloud-native architecture of the 5G core, where virtualized functions can be logically isolated and independently managed.

Each slice can have distinct attributes such as bandwidth, latency, and reliability. For example:

• An automotive manufacturer may require a slice with ultra-low latency and high reliability for autonomous robots and predictive maintenance.
• A public safety agency may need a highly redundant and secure slice for mission-critical communications.
• An energy provider could use a low-priority, high-throughput slice for collecting data from millions of smart meters.

Network slicing enables service-level differentiation, allowing Communication Service Providers (CSPs) to monetize their infrastructure by offering customizable service profiles to various industries. It also ensures that critical services can run in parallel without interference.

Because 5G core networks are built on microservices and deployed in cloud environments, slices can be dynamically scaled, provisioned, and decommissioned based on real-time needs. This automation is critical to meeting the evolving requirements of enterprise customers.

These same innovations are transforming how enterprises deploy and manage connected devices.

Explore our IoT Connectivity Solutions guide to see it in action

Best Practices for Successful Core Network Management

Security Vulnerabilities

Core networks are prime targets for cyberattacks due to their central role in managing subscriber data, authentication, and service delivery. As the network becomes more open through APIs and integrates third-party services via the Network Exposure Function (NEF), the attack surface increases. Malicious actors could exploit weak access controls, unpatched services, or misconfigured interfaces.

To mitigate these risks, core networks must be protected with security mechanisms such as intrusion detection, firewalls, and DDoS protection. Data privacy regulations and localization laws further increase the pressure on operators to secure user data, especially when deploying in multi-country or hybrid cloud environments.

Operational Complexity

The shift from hardware-based PNFs to cloud-native, microservices-based VNFs introduces new levels of operational complexity. Each component must be deployed, scaled, updated, and monitored independently. While this increases flexibility, it also requires skilled personnel and orchestration tools to manage the distributed system.

Furthermore, in roaming scenarios, limited visibility into partner networks can delay troubleshooting and resolution. Manual intervention in network operations leads to increased error rates, longer downtimes, and higher operational costs. Automation and unified observability are essential to overcoming these complexities.

Latency and Throughput Requirements

As real-time services like autonomous vehicles, industrial automation, and immersive media become mainstream, the latency and throughput demands on the core network intensify. Routing all data through centralized data centers—especially across borders—introduces delay and can violate local regulations.

Deploying User Plane Functions (UPFs) at the network edge helps mitigate these issues, but it also requires a scalable, distributed infrastructure. Ensuring consistent performance across geographies, particularly in hybrid deployments, adds to the implementation challenges.

FLOLIVE^® : Core Network Solution

Enhance Security Through Zero Trust Architecture

The openness and programmability of the 5G core—particularly with the introduction of network exposure through APIs—require a hardened security posture. A Zero Trust Architecture (ZTA) enforces the principle of “never trust, always verify,” meaning that every access request, even from within the network, must be authenticated and explicitly authorized.

This approach involves securing every microservice interaction using mutual TLS, enforcing role-based access control (RBAC), and segmenting the network to limit lateral movement of threats. API gateways can throttle and monitor external access, ensuring that only authorized applications or users can interact with exposed network functions. Real-time monitoring, anomaly detection, and automated incident response mechanisms should be embedded in the core to rapidly detect and neutralize threats.

ZTA is especially important in cloud-native environments where workloads are distributed and change frequently, increasing the potential for configuration drift and vulnerabilities.

Optimize Network Design and Operations

To support the dynamic demands of 5G and beyond, operators must rethink traditional network architectures. A cloud-native, microservices-based design enables distributed deployment, high availability, and granular control over each network function. This architecture should be platform agnostic, allowing deployment on private clouds, hyperscalers like AWS and Google Cloud, or hybrid models.

Operational agility improves when functions like UPFs, SMFs, and AMFs are decoupled and independently scalable. Operators can deploy closer to users—for instance, placing UPFs at the edge to reduce latency for critical applications—while centralizing less time-sensitive functions.

In addition, a modular architecture enables faster innovation and reduced time-to-market for new services, including those deployed as-a-service. This level of flexibility ensures CSPs can serve multiple customer types (e.g., IoT providers, public safety, industrial clients) on the same physical infrastructure while tailoring services per slice.

Implement Continuous Configuration Automation

Manual configuration of network elements introduces risk and cannot scale to meet the complexity of modern deployments. To address this, operators should adopt infrastructure-as-code (IaC) principles, allowing automated provisioning, version control, and consistent replication of configurations across environments.

Continuous automation ensures that network functions scale automatically based on real-time load, and it facilitates rolling updates and zero-downtime deployments, minimizing service disruptions. Automation also accelerates recovery from failures through predefined policies and self-healing workflows.

Operators can further reduce configuration drift and ensure policy compliance by integrating automation tools with orchestration and monitoring platforms. This tight integration supports both operational consistency and rapid response to changing conditions or faults.

Establish Robust Orchestration and Service Assurance Mechanisms

Orchestration is the central nervous system of a modern core network, responsible for coordinating the lifecycle of all virtualized and physical functions. A robust orchestration framework must support policy-driven deployment, healing, scaling, and retirement of services in real time.

Integrated service assurance tools should provide full visibility across the control and user planes, spanning from data centers to edge deployments. Monitoring must cover key metrics like latency, throughput, error rates, and resource utilization. When combined with analytics and AI/ML-driven insights, these tools can predict potential issues before they affect customer experience.

Orchestration platforms should also integrate with service-level agreement (SLA) enforcement mechanisms to automatically adjust resources or reroute traffic to meet performance commitments, ensuring high availability and customer satisfaction.

Ensure Compliance and Documentation

Data privacy regulations—especially data localization requirements—present a growing challenge for multinational CSPs. Operators must ensure that user data remains within the required geographic boundaries, which necessitates intelligent traffic routing, geo-fencing policies, and localized deployments of UPFs and other sensitive functions.

Compliance also requires continuous documentation of network topologies, policies, and data flows. Automated compliance audits, driven by orchestration tools, can verify that configurations align with regulatory requirements and trigger alerts if violations occur.

Well-maintained documentation is not only essential for regulatory audits but also supports faster incident response, troubleshooting, and onboarding of new services or staff. CSPs should integrate compliance checks into their deployment pipelines and maintain detailed logs of access, configuration changes, and service interactions to support auditability.