Provided is a method of estimating a queuing delay. The method includes: obtaining a round trip time (RTT) reference value, a forward one-way transmit time (OTT) reference value and a backward OTT reference value; and in accordance with a determination of whether a first increment rate is larger or smaller than a second increment rate, updating one of the forward OTT reference value and the backward OTT reference value based on the RTT reference value, the first increment rate being a rate of increment in local time of the transmitter, the second increment rate being a rate of increment in local time of the receiver.