We measured the packet-loss ratio, its time dependency, and the frequency of burst packet losses in Internet end-to-end communications. To do this, we developed a tool that sends and receives UDP (user datagram protocol) packets. Our measurements showed that long burst losses are more likely when the packet-loss ratio is high. We then examined two models for calculating the burst packet loss, an independent-loss model and a Marcov-chain model, to see whether they explain the packet-loss characteristics we measured. They did not, so we developed a sine model, in which the packet-loss probability depends on the time of day. Theoretical analysis and simulations showed that this model explains the characteristics of the burst packet losses characteristics we measured.