352-001 · Question #276
On a VoIP solution design, which option shows one-way latency, packet loss, and jitter measurements that ensure acceptable voice quality?
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
How the community answered
(34 responses)- A3% (1)
- B94% (32)
- C3% (1)
Why each option
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.
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.
Option B presents 130 ms one-way latency (below the 150 ms limit), 0.5% packet loss (below the 1% threshold), and 30 ms jitter (at the recommended maximum), making it the only choice where all three metrics are simultaneously within acceptable bounds. Exceeding any single threshold degrades the Mean Opinion Score (MOS) significantly, which is why the other options fail despite having one or two acceptable values.
Packet loss of 1.25% exceeds the 1% threshold, causing noticeable voice clipping and dropped syllables even though latency and jitter are within range.
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
Source: https://www.cisco.com/c/en/us/support/docs/voice/voice-quality/7934-bwidth-consume.html
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