352-001 Question #276: Real Exam Question with Answer & Explanation

The correct answer is B: Latency: 130 ms Packet loss: 0.5% Jitter: 30 ms. Per ITU-T G.114 and Cisco VoIP design guidelines, acceptable voice quality requires one-way latency under 150 ms, packet loss under 1%, and jitter under 30 ms - only option B satisfies all three thresholds.

Question

On a VoIP solution design, which option shows one-way latency, packet loss, and jitter measurements that ensure acceptable voice quality?

Options

ALatency: 110 ms Packet loss: 1% Jitter: 40 ms
BLatency: 130 ms Packet loss: 0.5% Jitter: 30 ms
CLatency: 150 ms Packet loss: 1.25% Jitter: 20 ms
DLatency: 170 ms Packet loss: 0.75% Jitter: 10 ms

Explanation

Per ITU-T G.114 and Cisco VoIP design guidelines, acceptable voice quality requires one-way latency under 150 ms, packet loss under 1%, and jitter under 30 ms - only option B satisfies all three thresholds.

Common mistakes.

A. Although latency (110 ms) and packet loss (1%) are within limits, the jitter value of 40 ms exceeds the recommended 30 ms maximum, which introduces audible distortion and gaps in speech.
C. Packet loss of 1.25% exceeds the 1% threshold, causing noticeable voice clipping and dropped syllables even though latency and jitter are within range.
D. One-way latency of 170 ms exceeds the ITU-T G.114 recommended maximum of 150 ms, introducing a perceptible delay that causes conversational overlap and echo issues.

Concept tested. VoIP QoS design thresholds - latency, jitter, packet loss

Reference. https://www.cisco.com/c/en/us/support/docs/voice/voice-quality/7934-bwidth-consume.html

Community Discussion

No community discussion yet for this question.

Full 352-001 Practice