A call center has 500 agents with voice, video, and bulk file transfers sharing a 100 Mbps edge. Voice needs strict priority with policing, while video and bulk need assured shares without starvation during congestion. Which scheduling and queue-class approach should the engineer apply to meet both needs?
Select an answer to reveal the explanation.
Short Explanation
Voice cannot wait in line behind backups. You protect calls with LLQ priority and give the rest fair guaranteed slices instead.
Full Explanation
QoS scheduling uses low-latency queuing to provide strict priority with policing for voice so delay stays low while preventing starvation, plus bandwidth-percent classes to guarantee minimum shares for video and bulk during congestion with fair excess distribution. Giving voice only bandwidth percent fails because it provides a share without strict priority, so queuing delay rises when bulk bursts fill the link. Putting video and bulk into LLQ fails because multiple strict-priority queues defeat the priority intent and can starve other classes. Using strict tail-drop for video and bulk fails because tail drop without guaranteed bandwidth does not assure shares and causes indiscriminate loss under congestion. Exam caveat is that LLQ must be policed and limited to a small percentage of link bandwidth, and practical check is to verify queue counters, drops, and voice jitter before and after enabling the policy.