Introduction

The telecommunications industry relies heavily on their core network, which

is essential for enabling communication and data transfer. As technology
advances and data demand increases, these core networks pose significant
challenges. Telcos may face immense difficulties in ensuring fast data
transfer, maintaining network reliability, and securing communications. At
the same time, the transition to technologies like 5G adds to these
challenges, requiring substantial infrastructure changes. In this post, we will
analyse the primary pain points faced by the industry and consider how
different core network designs can address these challenges.

This discussion aims to provide a clear understanding of core network

requirements and design choices, offering insights for telecommunications
professionals and stakeholders. By examining these critical aspects, we can
better understand how to develop core networks that meet current and
future demands, ultimately improving network performance and user
experience.

Core network requirements

The core network is the backbone of any telecommunications system, as it

ensures the smooth and efficient transmission of data and communication
signals. For a core network to function optimally, it must meet several key
requirements that cater to both current and future demands.

First is reliability. Reliability is a non-negotiable requirement for the core

network: it must provide consistent and uninterrupted service. This involves
robust fault-tolerance mechanisms, redundancy, and fail-over capabilities to
ensure that the network remains operational even in the event of hardware
or software failures. High reliability is critical for maintaining user trust and
meeting service level agreements (SLAs).

The second key requirement is security, an equally essential factor. As cyber

threats become more sophisticated, the core network must incorporate
advanced security measures to protect sensitive data and prevent
unauthorised access. This includes encryption, intrusion detection systems,
and regular security audits to identify and mitigate vulnerabilities.

Scalability is another crucial requirement. With the rapid growth of data

traffic and the increasing number of connected devices, the core network
must be able to expand and accommodate this growth without compromising
performance. Scalability ensures that the network can handle peak loads and
future expansion without requiring a complete overhaul.

Telco operators also need to prioritise low latency, as it is vital for real-time
applications such as voice calls or video conferencing, and emerging
technologies like autonomous vehicles and augmented reality. The core
network must be designed to minimise delays and ensure fast data
transmission, enhancing the user experience.

Interoperability is also important, as it enables the core network to work

seamlessly with various technologies and systems. This is particularly
relevant in a multi-vendor environment, where equipment from different
manufacturers must operate together without issues. Standardisation and
adherence to industry protocols facilitate this interoperability.

Finally, cost-effectiveness cannot be overlooked. The core network must

provide a balance between performance and cost, ensuring that it delivers
high-quality service without excessive expenditure. Efficient resource
management and innovative technologies can help achieve this balance,
making it feasible for operators to maintain and upgrade their networks
economically.

Design options

The design of a core network significantly impacts its performance,

scalability, and reliability. Telco operators have several architectural options,
each with distinct benefits and challenges.

Traditional core network architectures

Traditional core network designs rely on dedicated hardware and proprietary

systems. These architectures are robust and well-tested but can be inflexible
and costly to upgrade. This approach relies on physical infrastructure, which
often leads to higher operational costs and longer deployment times.

Virtualisation and Software-Defined Networking (SDN)

Virtualisation and SDN represent the first modernisation approach to

decoupling hardware and software in the core network design. Virtualisation
abstracts network functions from hardware, allowing them to run on standard
servers. This increases flexibility and reduces costs. SDN separates the
control plane from the data plane, enabling centralised network
management and more efficient resource utilisation. However, transitioning
to virtualised and SDN-based networks can be complex and require
significant investment in new skills and technologies.

Cloud-based core networks

Cloud-based solutions leverage cloud computing to host core network

functions. This approach offers scalability, agility and cost savings by utilising
cloud infrastructure. Operators can quickly scale resources up or down based
on demand, therefore improving their efficiency. The main challenges of this
approach are data security and the potential for increased latency,
depending on cloud provider performance and network configuration.

Private cloud and cloud-ready apps

Private cloud solutions offer a balance between the scalability of public

clouds and the control of traditional infrastructure. They allow operators to
manage resources securely within their own environment, using automation
tools that are similar to the ones used in public clouds for provisioning
compute, storage and networking. Cloud-ready applications are designed to
run efficiently in cloud environments, ensuring better performance and
easier management.

Cloud-native core network architecture

Cloud-native architecture focuses on building and running applications that

exploit the advantages of cloud computing models. These applications are
typically built as micro-services, deployed in containers, and managed by
orchestration platforms like Kubernetes. This approach enhances agility,
scalability, and resilience.

Hybrid approaches

Many operators adopt a hybrid approach, combining traditional and modern

design elements. This allows for a gradual migration to newer technologies
while maintaining the stability of legacy systems. Hybrid networks can
provide a balance between innovation and reliability, making the transition
smoother and more manageable.

5G Non-Standalone vs Standalone

In the context of 5G, non-standalone (NSA) and standalone (SA) architectures

offer different pathways for deployment. NSA uses existing 4G infrastructure
for control functions, with 5G providing enhanced data capabilities. This
allows for faster deployment and lower initial costs. Conversely, SA
architecture utilises a completely new 5G core, delivering full 5G benefits
such as ultra-low latency and advanced network slicing. While SA promises
superior performance, it requires significant investment in new
infrastructure.
By understanding these design options, telco operators can choose the best
approach for their specific needs, ensuring their core networks are robust,
scalable, and future-ready.

Key functions of the 5G core network

The 5G non-roaming reference architecture (source: 3GPP TS 23.501 V18.6.0)

The 5G core network (5GC) is a pivotal component of the next-generation

mobile network, enabling advanced features and capabilities. 5GC has
several key features and functions, including:

1. User Plane Function (UPF)

The UPF handles the data traffic for user devices, ensuring efficient
routing and forwarding of packets between the network and external
data networks.

2. Access and Mobility Management Function (AMF)

The AMF manages connection and mobility for 5G devices (UE – User
Equipment), handling authentication, registration, and mobility
management to ensure seamless user experience.

3. Session Management Function (SMF)

The SMF is responsible for session establishment, modification and
 release. It manages IP address allocation and quality of service (QoS)
parameters for user sessions.

4. Network Slice Selection Function (NSSF)

The NSSF allocates network resources to different network slices,
allowing multiple virtual networks to operate on the same physical
infrastructure, tailored to specific service requirements.

5. Policy Control Function (PCF)

The PCF provides policy rules to control network behaviour, including
QoS management, charging, and access control, ensuring optimal
resource utilisation and adherence to service agreements.

6. Unified Data Management (UDM)

The UDM centralises user data management, including subscriber
profiles and authentication credentials, ensuring consistent and secure
access across the network.

7. Network Exposure Function (NEF)

The NEF provides APIs for external applications to interact with the 5G
network, enabling new services and integration with third-party
systems.

8. Network Repository Function (NRF)

The NRF maintains an inventory of network functions and their
capabilities, allowing for dynamic discovery and interaction among
different network components.

Major pain points in core network design and implementation

Designing and implementing a core network involves several challenges that

telco operators must navigate.

Technical challenges

Scalability remains a major issue. As the number of connected devices and

data traffic increases, networks must expand efficiently without performance
loss. Reducing latency is also critical, especially for real-time applications like
video calls and gaming. Integrating new technologies with existing legacy
systems can be complex and costly. Operators need solutions that allow for
smooth integration without extensive overhauls.

Operational challenges
Provisioning, maintaining and upgrading the network poses significant
challenges. Regular maintenance is necessary to ensure reliability and
performance, but it can be disruptive and expensive. Telcos often encounter
difficulties in automating and streamlining the process of setting up network
services for new customers. Inefficient provisioning can lead to delays,
increased operational costs, and customer dissatisfaction. Security and
privacy concerns are ever-present, as networks must protect against
increasingly sophisticated cyber threats. Ensuring network reliability and
uptime is crucial, as outages can lead to substantial financial losses and
damage to reputation.

Strategic challenges

Cost management is a key concern. Building and upgrading core networks

require substantial investment, and operators must balance performance
with cost-efficiency. Keeping up with rapid technological advancements
demands continuous learning and adaptation, which can strain resources.
Regulatory and compliance requirements add another layer of complexity, as
operators must adhere to various standards and regulations.

Energy costs and environmental footprint

Energy consumption is a significant pain point for telco operators. Running

and cooling network infrastructure requires substantial amounts of energy,
contributing to high operational costs. Additionally, the environmental
footprint of these energy demands is considerable, leading to increased
scrutiny from regulatory bodies and environmentally conscious consumers.
Operators must seek energy-efficient solutions and renewable energy
sources to mitigate these impacts, balancing performance with sustainability.

Leveraging open source solutions

Telco operators can leverage open source solutions to address some of these
challenges. Open source software offers flexibility and cost savings by
reducing reliance on proprietary systems. It allows operators to customise
solutions to fit their specific needs and integrate them more easily with
existing systems. Open source communities provide a collaborative
environment where operators can share knowledge and resources,
accelerating innovation and problem-solving.

Adopting open source technologies also presents an opportunity for telcos to

transform into techcos. By embracing a tech-first approach, telcos can adopt
DevSecOps practices, integrating development, security, and operations to
drive continuous innovation. DevSecOps fosters a culture of collaboration
and efficiency, enabling faster deployment of new features and
improvements while maintaining high security standards.

This transformation allows telcos to participate more actively in the tech

growth, contributing to and benefiting from the collective advancements of
the open-source community. By leveraging open source solutions and
adopting DevSecOps practices, telco operators can enhance scalability,
improve security, and reduce costs. This approach helps manage the
complexities of core network design and implementation more effectively,
ensuring robust and future-ready networks.

Conclusion

In the rapidly evolving telecommunications landscape, addressing the

challenges of core network design and implementation is critical. Telco
operators must ensure scalability, reliability, security, and cost-effectiveness
to meet growing demands. Canonical offers a robust portfolio of open-source
infrastructure software that can help telcos overcome these challenges and
drive innovation.

Canonical’s software, including Ubuntu, OpenStack, Kubernetes,

and MicroCloud, provide flexible and scalable infrastructure options. Ubuntu
is renowned for its stability and security, making it a reliable choice for core
network operations. OpenStack offers a powerful platform for building private
clouds, enabling operators to efficiently manage and scale their resources.
Kubernetes facilitates container orchestration, allowing for the deployment
and management of applications in a consistent and automated manner.
MicroCloud extends these capabilities to edge environments, ensuring
consistent performance across diverse locations.

Additionally, Canonical’s Ubuntu Pro enhances security and support with

features such as Expanded Security Maintenance (ESM) and live kernel
updates. Ubuntu Pro provides up to 12 years of security coverage for over
30,000 packages, ensuring compliance with standards like HIPAA, FIPS, and
GDPR. It reduces average CVE exposure time from 98 days to just one,
offering peace of mind with enterprise-grade support and long-term
maintenance. Canonical Secure Software Development Lifecycle (SSDLC)
also participates in helping telcos ensure they comply with the latest
telecommunications and security regulations, including the UK’s
Telecommunications Security Code of Practice (TSCP), the EU’s Cyber
Resilience Act, and the US’ Federal Information Processing Standards (FIPS).
Canonical’s open source solutions and comprehensive support services
empower telco operators to build efficient, scalable, and secure core
networks. By embracing these technologies, operators can stay ahead of
technological advancements, reduce costs, and deliver enhanced services to
their customers.