In one embodiment, data communication device includes a network interface to receive first packets over a network from another network device via a switch, which includes a buffer associated with a variable buffer delay, and packet processing circuitry to compute respective measures of delay over the network to the other network device over time responsively to the received first packets, find a minimum measure of delay over the network to the other network device responsively to at least some of the computed respective measures of delay, estimate a current measure of buffer delay of the buffer responsively to the found minimum measure of delay and a current one of the computed respective measures of delay, set a packet processing parameter responsively to the estimated current measure of buffer delay, and process second packets responsively to the set packet processing parameter.