The Teams test uses the sensors' underlying TCP ping capability, sending 100 TCP pings and tagging the pings with the proper DSCP/TOS field for voice. Based on the latency, jitter and packet loss the sensor computes a Mean Option Score (MOS) based on ITU-T Recommendation G.107. The test target for teams is an anycast IP address which Microsoft says resolves to the closest media relay of their network edge.
The test provides latency, jitter, packet loss and MOS values which range from 1 to 4.4. The following guide to MOS values can be used to determine VoIP quality:
4.4: Best score possible
4.3 – 4.4: Users very satisfied
4.0 – 4.3: Most users satisfied
3.6 – 4.0: Some users satisfied
3.1 – 3.6: Many users dissatisfied
2.6 – 3.1: Nearly all users dissatisfied
1.0 – 2.6: Not recommended
Since Skype for Business Online was retired on July 31, 2021, we recommend replacing your Skype for Business test with this new test.
On VOIP MOS tests, DSCP tag 48 is mapped to VoIP traffic on Wi-Fi and DSCP tag 46 is mapped to VoIP traffic on Ethernet.
VoIP MOS Tests and Proxies
It's not typically possible to ping through a proxy. Therefore a VoIP MOS test won't be executed on a proxied network unless the “Force TCP Ping” flag is explicitly set on that network’s settings. This is not recommended and is disabled by default. It should only be enabled if the ping goes direct.