Which tools measure QoS performance?

• A. SNMP polling and NetFlow only.
• B. IP SLA, interface queue statistics, and call-quality metrics.
• C. Bandwidth meters and jitter buffers.
• D. CPU utilization and memory usage metrics.

Answer: (B)

QoS performance is measured with tools that actively and passively reveal how well prioritized traffic is being treated end to end. IP SLA performs active probes between endpoints, yielding measurements such as round-trip time, jitter, and packet loss, which are essential to assessing QoS across a path and for voice quality metrics. Interface queue statistics show how packets are actually queuing and being discarded under congestion—queue depth, drops, and wait times reveal whether QoS policies are effectively shaping traffic. Call-quality metrics translate those measurements into user-perceived quality, often via MOS or R-factor, giving a direct sense of whether real-time traffic meets expectations. Together, these provide a complete view of QoS performance. SNMP polling and NetFlow mainly report traffic volumes and flow details, not end-to-end QoS measurements; bandwidth meters and jitter buffers focus on bandwidth capacity and playback buffering rather than comprehensive QoS assessment; CPU and memory usage reflect device health, not the behavior of QoS policies.