CompTIA Network+ (N10-009)Network TroubleshootingHard
During a VoIP deployment, users report that calls sound choppy and words are occasionally clipped, though no calls are dropped. A network engineer captures traffic and notices that RTP packets are arriving at highly inconsistent intervals, even though overall packet loss is minimal. Which performance issue is being described?
- ALatency
- BBandwidth saturation
- CJitter
- DAttenuation
Show answer & explanationAnswer & explanation
Correct answer: C. Jitter
Jitter is the variation in packet arrival times. For real-time applications like VoIP, inconsistent packet spacing—even with low overall loss—causes audio to sound choppy or clipped because the jitter buffer cannot smooth out the irregular delivery timing.
Why the other options are wrong
- A. Latency is the overall one-way or round-trip delay, not the variation in arrival timing described here.
- B. Bandwidth saturation would typically cause packet loss and dropped calls, not just timing inconsistency.
- D. Attenuation is signal loss over cable distance, unrelated to packet timing variation in a network capture.
Jitter
The variation in delay between packets arriving at their destination, which is especially disruptive to real-time traffic like voice and video.
- Measured in milliseconds; VoIP typically tolerates jitter under 30ms
- Caused by network congestion, route changes, or queuing delays
- Mitigated with QoS, jitter buffers, and traffic prioritization
Memory trick: Jitter is packets arriving 'jittery' — uneven spacing scrambles smooth audio.