Harnessing Hardware for High-Performance Traffic Management in VPP

Traffic Management (TM) is critical for predictable network performance. It controls packet priority, shapes transmission rates, and allocates bandwidth to meet SLAs in large-scale deployments such as ISPs, telecom networks, and data centers.

FD.io Vector Packet Processing (VPP), a widely adopted high-performance networking stack across these environments, currently relies on software-based TM. This introduces bottlenecks at scale: CPU overhead grows with traffic classes, latency spikes under load, and token bucket waste cycles. At 100G/200G and beyond, these limitations pose a critical risk of SLA violations.

The new TM framework addresses these challenges by offloading shaping and scheduling to hardware through a vendor-neutral architecture and a unified API that works across all platforms supporting traffic management in silicon.

Overview

The proposed TM framework integrates VPP with hardware traffic management engines in supported NICs, SmartNICs, and DPUs. It detects hardware capabilities, classifies flows in software, and steers them to hardware queues where TM policies are enforced at line rate—eliminating software-based per-packet arbitration.

Key Features

Hierarchical Scheduling: Organizes traffic into multi-level queues to prioritize critical services while preserving fairness across remaining traffic. Dual-Rate Shaping: Applies committed and peak rate control with burst handling, compliant with RFC 2698, to prevent congestion and maintain predictable performance. Priority and Fairness: Combines strict priority for latency-sensitive traffic with weighted sharing for bulk flows to balance resources. Policing: Enforces traffic limits at line rate by dropping or marking packets appropriately.

Advantages of Traffic Management in Hardware

Performance: Delivers line-rate Traffic Management with high accuracy and low latency. Scalability: Supports thousands of queues at line rates without proportional CPU costs. Efficiency: Shifts workload to hardware, enabling CPUs to focus on application logic while reducing energy usage Reliability: Ensures stable Quality of Service under peak load conditions.

Conclusion

Hardware-assisted TM is no longer optional—it is mission-critical for networks scaling toward 400G/800G with diverse traffic and tight latency budgets. The VPP TM framework delivers this through a vendor-neutral API, making VPP ready for demanding telecom and data center workloads while preserving its modular design. For open-source stacks like VPP, this is not just an enhancement—it’s a long-overdue capability.