Stream Classification in Call Quality Dashboard

The Call Quality Dashboard (CQD) for Microsoft Teams and Skype for Business Online allows you to gain insights into the quality of calls made using Microsoft Teams and Skype for Business services. This topic provides detailed information about the quality classification of media streams. To learn more about CQD and how to enable it, see Turning on and using Call Quality Dashboard.

Classifier Definitions

Streams in CQD are classified as good, poor, or unclassified based on the values of the available key quality metrics. The metrics and conditions used to classify stream are shown in the tables below. CQD's "Poor Due To" dimensions can be used to understand which metric is responsible for a poor classification. See Dimensions and measures available in Call Quality Dashboard for more information on these dimensions.

Audio Classifier

An audio stream is marked as poor if one or more of the following conditions are met:

Metric Condition Explanation
Audio Degradation Avg > 1.0 Average Network Mean Opinion Score degradation for stream. Represents how much the network loss and jitter has impacted the quality of received audio.
Round Trip > 500 Average network propagation round-trip time computed as specified in RFC3550 in milliseconds.
Packet Loss Rate > 0.1 Average packet loss rate for stream.
Jitter > 30 Average jitter for stream in milliseconds.
Ratio Concealed Samples Avg > 0.07 Average ratio of the number of audio frames with concealed samples generated by packet loss healing to the total number of audio frames.

Video Classifier

A video stream is marked as good or poor based on the value of the first available metric in the following order:

Step # Metric Condition Classification if Condition is True Classification if Condition is False Classification if Metric is Unavailable Explanation
1 Video Local Frame Loss Percentage Avg > 50% Poor Good Proceed to step 2 Average percentage of video frames lost as displayed to the user. This includes frames recovered from network losses.
2 Video Frame Rate Avg < 7 Poor Good Proceed to step 3 Average frames per second received for a video stream, computed over the duration of the session.
3 Video Post FECPLR > 0.15 Poor Good Unclassified Packet loss rate after FEC has been applied aggregated across all video streams and codecs.

VBSS Classifier

A VBSS stream is marked as good or poor based on the value of the first available metric in the following order:

Step # Metric Condition Classification if Condition is True Classification if Condition is False Classification if Metric is Unavailable Explanation
1 Video Local Frame Loss Percentage Avg > 50% Poor Good Proceed to step 2 Average percentage of video frames lost as displayed to the user. This includes frames recovered from network losses.
2 Video Frame Rate Avg < 2 Poor Good Proceed to step 3 Average frames per second received for a video stream, computed over the duration of the session.
3 Video Post FECPLR > 0.15 Poor Good Unclassified Packet loss rate after FEC has been applied aggregated across all video streams and codecs.

Application Sharing Classifier

An application sharing stream is marked as poor if one or more of the following conditions are met:

Metric Condition Explanation
Spoiled Tile Percent Total > 36 Percentage of tiles that are discarded instead of being sent to a remote peer (for example, from the MCU to a viewer). Discarded (or spoiled) tiles may be caused by bandwidth restrictions between client and server.
AppSharing RDP Tile Processing Latency Average > 400 Average latency in milliseconds processing tiles on the RDP Stack at the conferencing server.
AppSharing Relative OneWay Average > 1.75 Average relative one-way delay between the endpoints in seconds for application sharing streams.

Unclassified Streams

In CQD, a stream is marked unclassified when ICE connectivity fails or when all the metrics required to compute the stream classification are not reported.

To check for ICE connectivity failures, examine the dimensions "First Connectivity Ice" and "Second Connectivity Ice" for a "FAILED" value. If either value indicates a failure, the stream will be marked as unclassified.

If ICE connectivity succeeded for an unclassified stream, the stream is likely considered unclassified because key stream metrics were not reported. There are a few reasons these metrics may not be reported:

  • QoE reports were not received - The metrics used for classification are reported in a QoE report sent at the end of a call. If this report is not produced (e.g., because some third-party endpoints may not send QoE) or was not able to be sent (e.g., because of a network outage), CQD is unable to classify the stream.

Tip

The "QoE Record Available" dimension can be used to determine whether a QoE report was received for a stream. Note that this dimension will have a value of "True" if a QoE report was received from either endpoint. A QoE report from both endpoints is required for the most accurate reporting of metrics.

  • Short calls - Short calls may not have enough media activity to compute key stream metrics. Without these metrics, CQD is unable to classify the stream.

Tip

The dimensions "Duration (Seconds)", "Duration (Minutes)", "Duration 5 seconds or less", and "Duration 60 seconds or more" can be used to determine the duration of a stream. The measurement "Avg Call Duration" can also be used to compute the average duration for a set of streams.

  • Low packet utilization - Like the "short call" scenario, sufficient packet utilization is required for computation of key stream metrics. Without these metrics, CQD is unable to classify the stream.
    • A common low packet utilization scenario occurs when a user joins a meeting to listen to the presenter but never speaks (likely muting the microphone for most of the call). In such a scenario, one audio stream will have high packet utilization (inbound to the client) while the other will have little to no packet utilization (outbound from the client). In this scenario, the duration of the stream may be an hour or longer but the packet utilization on the stream from the client to the server will be extremely low due to the microphone being muted, resulting in an unclassified stream.

Tip

The "Packet Utilization" dimension and "Avg Packet Utilization" measurement can be used to determine the packet activity of a stream.

Turning on and using Call Quality Dashboard (CQD)

Dimensions and measures available in Call Quality Dashboard

Use Call Analytics to troubleshoot poor call quality