Supported by the National High-Tech Research and Development Plan of China under Grant No.2002AA121032 (国家高技术研究发展计划(863)); the Institute of Computing Technology Youth Fund of China under Grant No.20026180-14 (计算技术研究所青年基金)
A key issue in one-way delay measurement is the removal of relative clock offset in the situation of without external clock synchronization mechanisms for the end-to-end hosts. Most researches are based on the assumption that the clock skew retains constant and without clock adjustments and drifts during measurement. But in fact, it is found that end system clock might be subject to gradual or instantaneous clock adjustments and frequency adjustments in operation. In this paper, with the time series segmentation technology, we discuss the detection of clock dynamics in one-way delay measurement. Two algorithms are proposed to estimate the relative clock offset in post facto and on-line mode respectively, while with only unidirectional probe packets. The computational complexity of the post facto algorithm is of order O(N2). Experiments show that these algorithms can provide reasonable clock dynamics detection and informative one-way delay estimation.