A high-speed network is often configured with a five-class QoS model. Which classes are used in the model?

While voice, video, signaling, critical data, and best-effort are traffic types, 'scavenger' is a specific and distinct class often included in a five-class model that is missing here.

The Cisco five-class QoS model typically includes Real-time (voice/interactive video), Call-Signaling, Critical Data, Best-Effort, and Scavenger classes, each with appropriate prioritization and bandwidth allocation based on their service level requirements.

'Drop-class' is not a standard named class in the same way 'scavenger' is for low-priority traffic.

This option incorrectly lists 'drop-class' instead of 'scavenger' and incorrectly implies call-signaling and real-time are separate top-tier classes without explicitly encompassing video/voice within 'real-time'.