In-band Network Telemetry for Software-Defined Wide Area Networks

Software-Defined Wide Area Networks (SD-WANs) have emerged as a transformative solution for modern enterprise networking, enabling dynamic traffic management, cost-efficient connectivity, and improved network performance. However, ensuring real-time visibility into network conditions remains a key challenge, as SD-WAN overlay tunnels operate over diverse and often unpredictable underlay networks. Traditional network monitoring techniques, such as active and passive monitoring, face limitations in balancing accuracy, responsiveness, and overhead. To address this challenge, we propose an In-Band Network Telemetry (INT) framework for SD-WANs, leveraging extended Berkeley Packet Filter (eBPF) technology for efficient and flexible packet processing. Our approach enables real-time telemetry data collection at the Customer Premises Equipment (CPE) level, allowing for precise performance monitoring while minimizing additional network overhead. The framework integrates seamlessly with various VPN-based SD-WAN tunnels, including Generic Routing Encapsulation (GRE), IP Security (IPSec), and IPSec over GRE, ensuring adaptability across different deployment scenarios. By embedding telemetry metadata directly into overlay packets, the proposed solution provides continuous monitoring of critical Quality of Service (QoS) metrics, such as One-Way Delay (OWD), Two-Way Delay (TWD), and packet loss rate. Through extensive experimentation, we demonstrate the effectiveness of our INT-enabled SD-WAN framework in accurately detecting network anomalies and ensuring Service-Level Agreement (SLA) compliance. The results validate our approach as a scalable and lightweight monitoring solution for enhancing network observability in SD-WAN deployments.