: We introduce an inline measurement method that can overcome difficulties in measurement task in high-speed network environment, such as short packet transmission intervals and Interrupt Coalescence function deployed in the high-speed Network Interface Cards. The method adjusts the number of packets involved in a packet burst of an active TCP connection, and utilises the inter-intervals of the bursts of the corresponding ACK packets for bandwidth measurement. Experiment results show that the proposed inline measurement method can measure the bandwidth in the network paths at least 1-Gbps or higher.