Which tunnel health monitoring mechanism measures latency, loss, and jitter between WAN Edge devices?

• A. Service Level Agreement Analysis (SLAAC)
• B. Bidirectional Forwarding Detection (BFD)
• C. Spanning Tree Protocol (STP)
• D. Control And Provisioning of Wireless Access Points (CAPWAP)

Answer: (B)

Tunnel health monitoring in SD-WAN relies on SLA monitoring to track performance metrics such as latency, jitter, and packet loss across tunnels between WAN Edge devices. These SLA probes continuously measure end-to-end performance and compare it to configured targets, helping determine the healthiest path for traffic and triggering failover when performance degrades. Bidirectional Forwarding Detection is about quickly detecting that a path is up or down, not about quantifying latency, jitter, or loss. Spanning Tree Protocol prevents loops at Layer 2 and doesn’t monitor tunnel performance. CAPWAP handles wireless access point tunnels, not WAN edge–to–WAN edge tunnel health.