Shifting from Vertical to Horizontal Cloud Stacks in Mobile Networks

The telecom industry is undergoing a significant transformation, with mobile operators increasingly moving away from traditional vertical cloud stack models toward more flexible horizontal architectures. This paradigm shift has profound implications for the way mobile networks are designed, deployed, and managed, and it demands a new approach to resiliency and systems integration from operators.

Vertical Cloud Stacks: A Simplified Past

Traditionally, mobile operators relied on vertical cloud stacks provided entirely by network function vendors. In this model, the vendor supplied all the components—including the network functions, the Kubernetes-based cloud platform, and the underlying hardware. This approach offered several advantages, particularly simplicity and a single point of accountability. Operators could depend on the vendor to ensure seamless integration of components and provide end-to-end support.

However, the vertical stack model also had significant limitations. It often led to vendor lock-in, reduced flexibility, and higher costs. Operators were constrained by the vendor’s technology roadmap and pricing structures. Additionally, the model lacked adaptability to keep pace with rapidly evolving cloud-native technologies and diverse network requirements, such as 5G’s demands for ultra-low latency and high scalability. Another major drawback was the lack of operational insight across the stack in production environments, essential for robust service assurance.

The Rise of Horizontal Cloud Stacks

To overcome these challenges, many mobile operators are now adopting horizontal cloud stack architectures. In this model, network function vendors supply only the network functions, while the Kubernetes-based cloud platform and underlying hardware are sourced from other vendors. This disaggregated approach allows operators to:

1. Reduce Vendor Lock-in:

   By decoupling the network functions from the cloud platform and hardware, operators gain the freedom to choose best-of-breed solutions from multiple vendors.

2. Optimize Costs:

   Competition among vendors for cloud platforms and hardware drives cost efficiency.

3. Enhance Innovation:

   Operators can adopt the latest advancements in cloud-native technologies and infrastructure without being tied to a single vendor’s offerings.

4. Achieve Greater Scalability and Flexibility:

   Horizontal stacks can be tailored to meet specific performance and scalability requirements of various use cases, from massive IoT deployments to high-throughput applications like augmented reality.

Operators as Systems Integrators

While horizontal cloud stacks bring significant benefits, they also introduce new complexities. In this model, the mobile operator assumes the role of a systems integrator. This shift represents a fundamental change in responsibilities and capabilities required of operators. They must now ensure that components sourced from multiple vendors integrate seamlessly and operate reliably as a cohesive system.

This integration role entails several key responsibilities:

1. Resiliency Assurance:

   Operators must ensure the system is resilient to failures. This includes designing for high availability, implementing robust disaster recovery mechanisms, and managing risks across the stack.

2. Interoperability Testing:

   With multiple vendors involved, rigorous testing is required to verify that network functions, cloud platform, and hardware work together without performance degradation or compatibility issues.

3. Resiliency Testing Across the Stack:

   Testing must encompass the entire horizontal stack, spanning network functions, the Kubernetes platform, and hardware from different vendors. This end-to-end testing ensures the system can handle failures and maintain service continuity despite diverse components.

4. Performance Optimization:

   Operators must monitor and fine-tune the system to achieve optimal performance. This involves balancing workloads, managing resource allocation, and ensuring low latency and high throughput.

5. Vendor Management:

   Operators must coordinate with multiple vendors to resolve issues, deploy updates, and ensure compliance with service-level agreements (SLAs).

Challenges of the New Model

The transition to horizontal stacks is not without challenges. One of the most significant hurdles is the need for operators to develop or acquire expertise in cloud-native technologies, systems integration, and operational resiliency. Historically, these areas have been managed by network function vendors in the vertical model.

Additionally, the multi-vendor nature of horizontal stacks complicates troubleshooting and accountability. When issues arise, determining the root cause and coordinating resolution efforts across different vendors can be time-consuming and resource-intensive.

Strategies for Success

To successfully navigate this shift, mobile operators should consider the following strategies:

1. Invest in Skills and Expertise:

   Building internal teams with expertise in cloud-native architectures, Kubernetes, and systems integration is critical. Operators may also consider partnering with specialized systems integrators or consultants during the transition.

2. Adopt Automation Tools:

   Automation can simplify system integration and management, from deployment and scaling to fault detection and recovery. Leveraging tools like CI/CD pipelines, Infrastructure as Code (IaC), and AI-driven monitoring enhances operational efficiency.

3. Establish Strong Governance:

   Clear governance frameworks are essential for managing multi-vendor environments. This includes defining roles and responsibilities, establishing escalation paths, and ensuring adherence to interoperability standards.

4. Focus on Resiliency:

   Operators should prioritize resiliency at every layer of the stack. This involves designing redundant architectures, conducting regular failure simulations, and implementing robust security measures to protect against cyber threats.

5. Collaborate with the Ecosystem:

   Engaging with industry initiatives, such as the Cloud Native Computing Foundation (CNCF) and the Next Generation Mobile Networks Alliance (NGMN), helps operators stay aligned with best practices and emerging standards.

The Road Ahead

The shift from vertical to horizontal cloud stacks marks a pivotal moment for mobile operators. While it brings challenges, it also opens the door to greater innovation, flexibility, and cost efficiency. By embracing their new role as systems integrators and investing in the necessary capabilities, operators can unlock the full potential of horizontal architectures and position themselves for success in the cloud-native era.

Ultimately, this transformation empowers operators to take control of their networks, foster innovation, and deliver the resilient, high-performance services that customers demand in a 5G world and beyond.

How Spirent Can Help

Spirent can help mobile operators navigate this transformation and ensure a seamless transition to horizontal cloud stacks. By providing comprehensive testing, validation, and assurance solutions, Spirent enables operators to mitigate risks, optimize performance, and achieve the resiliency needed to deliver reliable services across a diverse and complex ecosystem of technologies.

For more insights on cloud-native networks read our whitepaper Lab-to-Live: Delivering Resilient and Secure Cloud-Native Networks, created in collaboration with Appledore Research and explore our case study Cloud Consolidation Drives 35% Capex Reduction.