VoIP still suffering from audio delay

<<<... The best mean audio delay for a VoIP provider came in at 149 ms, while the worst came in at 279 ms. Even so, this was far better than the worst delay recorded in Keynote's September 2006 survey, which clocked in at 335 ms. VoIP's call completion percentage was also found lagging behind PSTN, as only two VoIP providers studied had call completion percentages over 99.5 percent. Six providers had completion percentages under 99 percent, with one provider scoring as low as 86.7 percent.

The most common audio problems for VoIP hard phone providers were audio holdover, which occurred in 68.13 percent of calls; front clipping, which occurred in 42.37 percent of calls; other kinds of clipping, which occurred in 58.27 percent of calls; and hum, which occurred in 31.98 percent of calls. While PacketCable had significantly lower percentages of audio problems in nearly all of its indicators, it did experience a higher frequency of holdover at 72.32 percent of calls.

PacketCable also performed better than PSTN in the number of calls that experienced back clipping, hiss, hum, other clipping and static. The study was conducted by placing over 125,000 total calls between New York and San Francisco over a period of a month. The latest study is Keynote’s fourth in comparing call quality for PSTN, VoIP and PacketCable.