Sub-optimal MOS indicates presence of user-detectable voice degradation

The measured MOS for this path indicates a reduced voice quality that would be detected by VoIP users.

Recommended action

  1. In the test results, identify sources of packet loss, latency, and jitter.
  2. Review other VoIP-related diagnostics.
  3. Review choice of codec and overall call load.
  4. Address any defects and retest.

Detailed explanation

This observation message is primarily related to the measured Mean Opinion Score (MOS). MOS is a subjective score relative to a user’s experience. It is a function of loss, latency, and jitter. It also varies with the voice codec used and the overall call load. The severity shown reflects what was measured. To determine if this MOS value is within a typical range, compare it with the "Best MOS" and "Worst MOS" values generated in the test results.

Possible secondary messages

  • "Packet loss identified as major cause"
  • "Excessive latency identified as major cause"
  • "Packet discards due to excessive jitter identified as major cause" In the case of excessive jitter, some packets are late arriving and therefore are discarded by the receiving host.
  • "Voice degradation inherent to the selected codec identified as major cause"

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