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While 5G networks are known for the federated design with a vast amount of infrastructure extended onto the network fabric, the core systems are still essential too.

5G has demanding service and network requirements that will require a fundamental change to the core architecture. 


Only a cloud-native core network can deliver the agility, automation, and efficiency that will enable Communications Service Providers (CSPs) to take full advantage of 5G technology.  Cloud-native goes beyond simply virtualizing network functions.  It implements Virtual Network Function (VNF) machines to host stateless and dataless microservices that access a common data layer.  The cloud-native core supports network slicing, distributed edge computing, programmability, analytics, and DevOps – all the capabilities that distinguish 5G.

The future of mobile communications will be very different from today’s experiences, with 5G connectivity affecting huge areas of our lives.  5G networks will offer data speeds in excess of 10 Gbps, extreme low latency, and ultra-reliable connections in a secured and trusted environment, with greater privacy compared to today’s networks.  Moreover, 5G will be a key enabler in transforming our economy and society by providing connectivity in three broad areas:

  • Extreme mobile broadband: Growing subscriber demands mean that future networks must deliver extreme capacity and performance.
  • Massive machine communication: The Internet of Things (IoT) needs secure communication between billions of sensors and the core network.
  • Critical machine communication: Ultra-reliable low latency communication will be increasingly required for the immediate control of robots and virtual reality/augmented reality services.

These 5G capabilities give CSPs an opportunity to win new revenue but will require the delivery of service-specific bandwidth and latency on demand with massive scalability.

The 3rd Generation Partnership Project (3GPP) has defined a new 5G Core architecture that supports service delivery over wireless, fixed, or converged networks.  This new 5G Core uses a cloud-aligned Service Based Architecture (SBA) that supports control plane function interaction, reusability, flexible connections and service discovery that spans all functions.  It also makes it easier to add new functions and scale them rapidly.


Like the 4G Evolved Packet Core (EPC), the 5G Core aggregates data traffic from end devices.  The 5G Core also authenticates subscribers and devices, applies personalized policies and manages the mobility of the devices before routing the traffic to operator services or the Internet.

While the EPC and 5G Core perform similar functions, there are some major differences in that the 5G Core is decomposed into a number of Service-Based Architecture (SBA) elements and is designed from the ground-up for complete control and user plane separation.  Rather than physical network elements, the 5G Core comprises pure, virtualized, software-based network functions (or services), and can therefore be instantiated within Multi-access Edge Computing (MEC) cloud infrastructures.

This new architecture will give operators the flexibility they need to meet the diverse network requirements of all the different 5G use cases, going well beyond high speed fixed wireless or mobile broadband services. And at the heart of the new 5G core architecture is cloud native software design.


To illustrate just how the 5G core network will be different from today’s EPC, here are some of the new 5G network functions that you will need to need to know about:

  • User Plane Function (UPF).  Emerging from Control and User Plane Separation (CUPS) strategies defined within non-standalone 5G New Radio specifications, the 5G core UPF represents the evolution of the data plane function of the Packet Gateway (PGW).  This separation allows data forwarding to be deployed and scaled independently so that packet processing and traffic aggregation can be distributed to the network edge.
  • Access and Mobility Management Function (AMF).  With the 4G EPC Mobility Management Entity (MME) decomposed into two functional elements, the AMF receives all the connection and session information from end user equipment or the RAN but only handles connection and mobility management tasks.  Anything to do with session management is forwarded to the Session Management Function (SMF).
  • Session Management Function (SMF).   A fundamental component of the 5G SBA, the SMF is responsible for interacting with the decoupled data plane by creating, updating and removing Protocol Data Unit (PDU) sessions and managing session context within the UPF.  Decoupling other control plane functions from the user plane, the SMF also performs the role of Dynamic Host Configuration Protocol (DHCP) server and IP Address Management (IPAM) system.

These are just some of the new network functions of the 5G Core Service Based Architecture.  The changes are quite radical compared to today’s 4G EPC, and one of the most important factors that will enable the new Service-Based Architecture is truly cloud native design and deployment methodologies.  5G Core network functions will need to be massively scalable, highly reliable and support automated operations.  As stated many times here in the other 5G blog posts, the 5G future will be cloud native.

5G SA Packet Core is equipped several new capabilities inherently built into to so that operators have flexibility and capability to face new challenges thrown open by the new set of requirements for varying new use cases.  The network functions in new 5G Core are broken down into smaller entities such as the SMF and UPF which can be used on a per service basis.  Gone are the days of huge network boxes, welcome to services that automatically register and configure themselves over the Service Based Architecture, which is built with the new functions like the NRF which borrow their capabilities from cloud native technologies.

Separation of the user plane has freed it from the shackles of the control plane state and permits deployments at the edge with very little integration overhead. Multi access edge computing that spans both wireless and wireline technologies will significantly redefine how the users connect to applications, corporate networks and each other.

Given below is the new 5G SA architecture as defined by 3GPP:

3GPP Core 1

Today’s networks are continuing along a path of transformation, as operators worldwide understand the benefits that software-based virtualized networks provide.  As this evolution continues and hardware becomes further disaggregated from software, operators will benefit from an accelerated rate of innovation driven by open interfaces capable of further disaggregating hardware from software that will allow new ecosystems to evolve capable of delivering a new breed of experiences and services.

Despite the many benefits this evolution will provide, it will also add a level of complexity to network design and management that will require operators to evolve from traditional (manual) network operations.  As a result, wireless operators globally are looking for ways to automate many of the traditional functions related to network management and allow them to achieve higher levels of profitability, redundancy and management.

To be successful wireless operators must embrace new innovative solutions that possess the openness, programmability, and automation required to support 5G.


Altiostar. (2019). Solutions. Altiostar. Retrieved on October 14, 2019 from,

Cisco. (2019). Cisco Ultra 5G Core Solution. Cisco. Retrieved on October 14, 2019 from,

Dredge, S. (2019). Introducing the 5G Core Network. Metaswitch Networks. Retrieved on October 14, 2019 from,

Nokia, (2019). Building a cloud native core for a 5G world: Realizing the promise of 5G. Nokia Oyj. Retrieved on October 14, 2019 from,

About the Author:

Michael Martin has more than 35 years of experience in systems design for broadband networks, optical fibre, wireless, and digital communications technologies.

He is a business and technology consultant. Over the past 15 years with IBM, he has worked in the GBS Global Center of Competency for Energy and Utilities and the GTS Global Center of Excellence for Energy and Utilities. He is a founding partner and President of MICAN Communications and before that was President of Comlink Systems Limited and Ensat Broadcast Services, Inc., both divisions of Cygnal Technologies Corporation (CYN: TSX).

Martin currently serves on the Board of Directors for TeraGo Inc (TGO: TSX) and previously served on the Board of Directors for Avante Logixx Inc. (XX: TSX.V). 

He has served as a Member, SCC ISO-IEC JTC 1/SC-41 – Internet of Things and related technologies, ISO – International Organization for Standardization, and as a member of the NIST SP 500-325 Fog Computing Conceptual Model, National Institute of Standards and Technology.

He served on the Board of Governors of the University of Ontario Institute of Technology (UOIT) [now OntarioTech University] and on the Board of Advisers of five different Colleges in Ontario.  For 16 years he served on the Board of the Society of Motion Picture and Television Engineers (SMPTE), Toronto Section. 

He holds three master’s degrees, in business (MBA), communication (MA), and education (MEd). As well, he has three undergraduate diplomas and five certifications in business, computer programming, internetworking, project management, media, photography, and communication technology. He has earned 15 badges in next generation MOOC continuous education in IoT, Cloud, AI and Cognitive systems, Blockchain, Agile, Big Data, Design Thinking, Security, and more.