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Surveyor

The Advanced Network & Services and the Common Solutions Group (CSG)2.1 operates the Surveyor [5] project. Surveyor is a contribution to the IPPM program. The project aims to ``create technology and infrastructure to allow users and service providers (at all levels) to have an accurate common understanding of the performance and reliability of given Internet paths and to have an accurate common understanding of what segment of a given Internet path limits that performance and reliability'' [5]. The participating sites in this project include U.S., European and Asian sites.

Surveyor makes one-way delay and loss measurements, using GPS devices to synchronise the time between the monitoring machines. Timestamped test packets are sent from one end of the path to the other. The one-way delay is computed by subtracting the timestamp in a test packet from the timestamp marking the arrival of the packet at the destination machine. The accuracy of the delay measurements is within 50 microseconds. The test packets are 40-byte UDP packets, sent as a Poisson [40] stream, usually at an average rate of two packets per second.


next up previous contents
Next: AMP Up: Measurement activities Previous: NIMI   Contents
Xing Deng
July 1999