A Unique Deployment with Karsolink
Working with Karsolink, a Italy-based regional operator, we designed a BNG deployment that breaks away from traditional BNG approaches. The forwarding plane (vBF) is deployed on cost-effective Intel Atom-based Silicom Cordoba Edge Gateway appliances, while the control (vBC) and management planes (vDB) are fully virtualized on a Proxmox cluster in a data centre.
This hybrid approach delivers the best of both worlds:
- Lightweight, efficient forwarding at the edge using low-power devices.
- Centralized orchestration and subscriber control using virtual machines that can scale elastically.
Introduction to 5×9 vBNG
The 5×9 vBNG (Virtual Broadband Network Gateway) is a fully software-based solution designed to decouple the management, control and forwarding plane. This separation provides operators with unprecedented flexibility: scaling each plane independently, running them on best-fit hardware, and upgrading without affecting subscriber sessions. Unlike monolithic BNGs tied to proprietary chassis, 5×9 vBNG embraces a cloud-native mindset — running in virtualized environments or on commercial off-the-shelf (COTS) hardware — without sacrificing carrier-grade reliability or feature richness.
5×9 vBNG consists of three elements: Virtual Dashboard (vDB), Virtual BNG Controller (vBC) and Virtual BNG Forwarder (vBF). What makes 5×9 vBNG special is its simple design, a unique vDB component that fully automates system provisioning and takes care of all intelligent system tasks like control plane handling, subscriber IP management, routing, workload distribution, redundancy, etc., minimizing the effort to keep everything up and running. 5×9 introduces the management plane with vDB, along with the control plane (vBC) and forwarding plane (vBF)
Forwarding Plane: Atom-Powered Edge Processing
The choice to run the forwarding plane on Intel Atom-based hardware is a key differentiator:
- Power Efficiency: Atom CPUs provide excellent performance per watt, making them ideal for edge sites where power and cooling budgets are constrained.
- Cost-Effectiveness: Compared to high-end x86 or custom ASIC platforms, Atom devices significantly reduce CAPEX without compromising essential throughput for small-to-medium subscriber bases.
- Flexibility: Because the 5×9 forwarding plane is software-based, it fully utilizes the capabilities of the Silicom Cordoba appliance, getting line-rate speeds on both 10GE optical interfaces and supporting up to several thousand dual-stack subscribers.
At the time of writing, the forwarding plane is deployed at two geographically separated locations, Karsolink gains redundancy and reduced subscriber latency, with more locations in future plans. This design keeps data paths local, while leaving complex subscriber management centralized.
Use of Micro vBNG PoPs based on Intel Atom HW does not exclude use of higher performant x86 HW on other locations with higher number of subscribers, thus enabling optimal COTS HW selection for specific ISP user distribution and termination of customer connections closer to customers, that would not be economically feasible with traditional BNG approach.
Control & Management Plane: Virtualized on Proxmox
In contrast, the control plane (session handling, routing, policy enforcement) and management plane (configuration, telemetry, automation) are hosted centrally on a Proxmox virtualization platform:
- Elastic Scaling: VMs can be resized or migrated in seconds, ensuring that subscriber growth never becomes a bottleneck.
- Centralized Visibility: Operators have a single pane of glass for monitoring, troubleshooting, and pushing configuration changes.
- Operational Simplicity: Maintenance on the control plane does not disrupt subscriber data forwarding, as the forwarding plane continues to function autonomously.
This mix of lightweight edge hardware and virtualized core intelligence is what makes the deployment uniquely modern and efficient.
Benefits of the Hybrid Design
Modern broadband networks demand agility, efficiency, and scalability that legacy chassis-based BNGs cannot deliver. 5×9 vBNG addresses this challenge by decoupling the management, control, and forwarding planes into a software-driven, cloud-native design – enabling operators to scale flexibly, reduce costs, and simplify operations. The hybrid 5×9 approach delivers the following benefits:
- Optimized TCO: Low-cost Atom hardware reduces edge expenses, while virtualization avoids the need for specialized control-plane appliances.
- High Availability: Dual-edge design and Proxmox HA clustering protect against both hardware and software failures.
- Future-Proofing: The architecture supports NFV/SDN integrations and can evolve towards containerized deployments without forklift upgrades.
- Environmentally Friendly: Atom-based devices consume less power, supporting Karsolink’s sustainability goals.
Conclusion
By combining Atom-based forwarding at the edge with a virtualized control and management plane in the core, Karsolink and 5×9 Networks have delivered a broadband network that is scalable, energy-efficient, and operationally streamlined. This architecture is a blueprint for ISPs seeking to balance performance, cost, and agility in the era of distributed networking.
Author: Branimir Rajtar, 5×9 Networks
