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WebRTC Metrics

A comprehensive overview of WebRTC statistics, derived indicators, and observable signals, to better understand call quality, connectivity, and user experience in rtcStats

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inboundvideonetwork

High video retransmission received

Retransmitted bytes make up a large share of all bytes received on inbound video, indicating heavy retransmission activity.

Description

This observation compares cumulative retransmittedBytesReceived to cumulative bytesReceived on an inbound video RTP stream. When retransmitted content accounts for a large fraction of everything received, the path is likely experiencing sustained loss or reordering that forces many retransmissions.

When does it trigger?

The observation is raised when:

retransmittedBytesReceived.total / bytesReceived.total >= 15%

Both totals must be present and positive. The threshold is applied to session cumulative totals; the log timestamp reflects the first sample where that cumulative ratio reaches at least 15%, when per-sample series are available.

Interpretation

  • Network loss or congestion: Lost or late packets drive NACKs and retransmissions, inflating retransmitted bytes relative to useful media content.
  • Reordering: Severe reordering can also trigger retransmissions before originals arrive.
  • Bandwidth cost: Retransmissions consume extra downstream (and upstream control-path) capacity and can interact badly with congestion control.

The retransmittedBytesReceived counter is only present when retransmissions can be identified; if it is absent, this observation cannot be computed.

See also