In the paper we describe a technique for measuring one-way packet delay and loss on the international Internet, and describe the use of this technique to characterize the Quality of Service (QoS) behavior of Internet connections, including packet loss, delay, and delay variation. The delay measurement techniue depends on the use of Global Positioning System (GPS) time receivers to provide an accurate absolute time reference at network measurement point. Packets in the network are characterized by a signature derived from the packet header and payload, and so can be recognized at the measurement points. Thus packet loss can be detected, and the time taken for a packet to move fromone measurement point to another can be measured with an accuracy of better than 10 microseconds. Measurements have been made on the Internet between New Zealand and the US, the UK, and Singapore, and have revealed a number of interesting phenomena on differing time-scales.
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