Understanding VoIP Qaulity Test

After running a 48 hour VoIP Quality Test, we review the results to see what the test found during the time it was running. When reading the results, notice that there are eight columns. Up and Down Jitter, Up and Down Packet Loss, Up and Down Packet Order, Packet Discards, and the MOS.

Within those columns, scores will appear in either green, orange, or red cells.

1. The IP where the test was ran. 
2. Jitter (Up and Down)
3. Maximum Jitter (Up and Down)
4. Packet Loss (Up and Down)
5. Paclet Order (Up and Down)
6. Packet Discards
7. MOS (score)
8. Red Cell (indicates a critical threshold score for that cell)
9. Orange Cell (indicates a warning threshold score for that cell) 

Cells with good or acceptable threshold scores remain green. 

(2) Jitter

Jitter is the variation in the time between packets arriving which can be caused by network congestion, timing drift, or route changes.

Measuring Jitter is done in milliseconds. Good or normal would be anything less than 10 ms. Warning Threshold is from 10 to 24. Critical Threshold is anything above 25 ms. Please note that these values are avarages.

(3) Maximum Jitter

Maximum jitter are the highest jitter values recorded during the given time. Idealy, values should be below 50 ms. 

(4) Packet Loss

Packet loss occurs when one or more packets of data travelling across a computer network fail to reach their destination.

Measuring Packet Loss is done by percentage. Good or normal would be anything less than 1%. Warning Threshold is from 1% to 2%. Critical Threshold is anything above 3%. (Keep in mind that any packet loss over 1% will have some kind of quality issue)

(5) Packet Order

Packet Order occurs when one or more packets of data travelling across a computer network arrive out of order.

Measuring Packet Order is done by percentage. The best is 100% and good or normal would be anything above 99%. Warning Threshold is from 99% to 97%. Critical Threshold is anything below 97%.

(6) Packet Discards

Packet Discards are packets that arrived, but were unusable because they either arrived too late or were malformed. 

Measuring Packet Discards is done by percentage. Good or normal would be anything less than 0.5%. Warning Threshold is from 0.5% to 1%. Critical Threshold is anything above 1%.

(7) MOS

Mean Opinion Score - MOS is a subjective measurement tool that is based on Opinion. The scale starts at 1 and goes to 5.

Measuring the MOS is done by using a scale. Good or normal would be anything above 3. Warning Threshold is from 3 to 2. Critical Threshold is anything below 2.