Which QoS tool can you use to optimize voice traffic on a network that is primarily intended for data traffic?

Question:
Which QoS tool can you use to optimize voice traffic on a network that is primarily intended for data traffic?

• WRED
• FIFO
• PQ
• WFQ

Explanation: With Priority Queueing (PQ), traffic is classified into high, medium, normal, and low priority queues. The high priority traffic is serviced first, then medium priority traffic, followed by normal and low priority traffic.  -> Therefore we can assign higher priority for voice traffic.

Also with PQ, higher priority traffic can starve the lower priority queues of bandwidth. No bandwidth guarantees are possible -> It is still good because this network is mostly used for data traffic so voice traffic amount is small.

With First In First Out (FIFO) or Weighted Fair Queueing (WFQ), there is no priority servicing so they are not suitable here.

Reference: https://www.cisco.com/c/en/us/td/docs/ios/solutions_docs/qos_solutions/QoSVoIP/QoSVoIP.html

Weighted Random Early Detection (WRED) is just a congestion avoidance mechanism. WRED measures the size of the queues depending on the Precedence value and starts dropping packets when the queue is between the minimum threshold and the maximum threshold -> It does not have priority servicing either.

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