Patent ID: 7330426

Claim:
A method of performing Round Trip Time (RTT) measurement in a data packet receiver using a Transmission Control Protocol (TCP) for communication via a network with a sender, said method comprising the following steps: sending an acknowledgment for a currently received data packet to the sender, measuring a first time instant when sending the acknowledgment, triggering, in response to receiving acknowledgments, at the sender the transmission of further data packets, calculating a sequence number of an expected data packet on the basis of the sequence number of the currently acknowledged data packet SN_ack, an advertised window awnd and a maximum segment size MSS according to the formula: SN _expect=SN — ack +( awnd −1) MSS, comparing a sequence number of received data packets with the calculated sequence number of the expected data packet, measuring a second time instant when a data packet is received whose sequence number is equal to or larger than the calculated sequence number of the expected data packet, and calculating the RTT measurement based on the measured first and second time instants.