Details: Call Tags

Calls can be tagged for one or more conditions that may influence the subjective experience of audio quality on the call. Tags are based on analysis of the call at the Twilio Gateway. The tags for carrier, client, and SIP edges are:

• silence: Silence detected on the line either due to a missing audio stream or a completely silent stream received.
• high_jitter: Two conditions can result in calls being tagged with high jitter. Jitter counts as high when the call meets one of two conditions:
  • The average jitter equals 5ms and the maximum jitter of 30ms.
  • More than one percent of packets gets delayed by 200ms or more.
• high_packet_loss: Packet loss that exceeds five percent.
• high_pdd: The time between the SIP INVITE request and an 18x response, the post-dial delay, took longer than 95 percent of all other calls (p95) for this country.
• high_latency: The average Twilio-internal Real-time Transport Protocol (RTP) traversal time for packets received at this edge to this call SID exceeded 150ms. The call SID that received the delayed packets is the one that is tagged.
• pstn_short_duration: A completed call that lasted under six seconds.
• hd_audio: The call carried wideband, or high-definition (HD), audio on at least one edge. HD audio means the AMR-WB or Opus codec; no other codec is counted as HD.
• downsampled: The call carried HD audio on at least one edge, but the longest portion of the call connected to a component or carrier that didn't support HD. That audio was converted to narrowband. This tag always accompanies hd_audio. It does not appear on its own.

SDK Tags are based on analysis of the call at the SDK sensors on the local device. They report on the cumulative condition of the media streams sent to the SDK from the Twilio Gateway. The tags for SDK edge are:

• high_latency: Round Trip Time (RTT) > 400 ms
• low_mos: Mean Opinion Score (MOS) < 3.5
• high_jitter: average jitter of 5ms and max jitter of 30ms
• high_packet_loss: >5% packet loss
• ice_failure: The ICE candidate has checked all candidates pairs against one another and has failed to find compatible matches for all components of the connection.