VoIP Gap Density by Call
The number of packets lost during a particular call's low-loss (or gap) periods exceeds the threshold set in Expert Thresholds. Contrary to what the terms imply, gaps are desirable while bursts may indicate a problem. From RFC 3611 (the RTCP XR specification): "Following a Gilbert-Elliott model, a period of time, bounded by lost and/or discarded packets with a high rate of losses and/or discards, is a "burst", and a period of time between two bursts is a "gap". bursts correspond to periods of time during which the packet loss rate is high enough to produce noticeable degradation in audio quality. Gaps correspond to periods of time during which only isolated lost packets may occur, and in general these can be masked by packet loss concealment.