A method for measuring one-way delays in a communications network, the method comprising: maintaining a virtual clock state comprising information for converting times measured with respect to remote clocks into times as would be measured with respect to a local reference clock; registering, for each packet of the plurality of packets in a communications session between the first and second nodes, a timeset comprising transmission and reception times at the first and second nodes; converting, responsive to the virtual clock, times in the timeset measured with respect to the first node clock or the second node clock, into times as would be measured with respect to the reference clock; calculating, for each packet of the series of packets, a forward one-way delay (FOWD) from the first node to the second node and a reverse one-way delay (ROWD) from the second node to the first node, responsive to the converted timeset.