VoIP Diagnostics FAQ

Prev Next

How is a Mean Opinion Score (MOS) calculated?

Probes monitor the voice traffic and record several measures for each media stream.

  • The number of lost packets.
  • The variance of delays between the received packets (jitter).
  • The distribution of lost packets inside the stream.
  • The codec used.

Based on these values, VoIP Diagnostics will estimate the MOS.

What are the MOS thresholds?

Very satisfied = over 4.33
Satisfied = 4.03 to 4.33
Some users dissatisfied = 3.60 to 4.02
Many users dissatisfied = 3.10 to 3.59
Nearly all users dissatisfied = under 3.10

What are the common registration status codes?

200 = Successful registration.
401 = Device failed to answer the authentication challenge. Check for SIP ALG.
403 = SIP password does not match. Restart the supported device to load a new configuration.
404 = User does not exist. Check the provisioning of the user and device.

What are the most common call status codes?

200 = Successful call.
480 = Unable to reach remote party.
486 = Call has been rejected on a specific device.
487 = Caller has terminated the call before the remote party has answered.
603 = Call has been rejected by the user.