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Precise Latency Measurement of Unidirectional-Data-Flow Network Equipment



I-Chun Chao, Kang B. Lee, Frederick M. Proctor, Chien-Chung Shen, Fan-Ren Chang


In regards to network performance measurements, many timing indices, such as latency, jitter, and one-way delay (OWD), are getting more attention because real-time applications and needs are pushing higher network capabilities. Data latency in a network can be measured by placing additional unidirectional-data-flow (UDF) devices, such as test access taps (TAPs), on the network path. However, this can create severe uncertainty to the timing measurement when sub-microsecond precision measurements need to be achieved. This paper proposes the Precision Time Protocol (PTP)-Based Measurement method for measuring latency of a UDF device based on traditional OWD measurements. In addition, we propose a Packet-by-Packet Precise Measurement method, which can further reduce the measurement uncertainty caused by the limit of precision in the PTP synchronization protocol in the PTP-Based Measurement method, by strictly calculating the latency for each packet.
Proceedings Title
2014 IEEE International Frequency Control Symposium
Conference Dates
May 19-22, 2014
Conference Location
Taipei, TW


IEEE 1588, Latency Measurement, One Way Delay, Packet-by-Packet Precise Measurement Method, Precision Time Protocol, PTP, PTP-based Measurement Method


Chao, I. , Lee, K. , Proctor, F. , Shen, C. and Chang, F. (2014), Precise Latency Measurement of Unidirectional-Data-Flow Network Equipment, 2014 IEEE International Frequency Control Symposium, Taipei, TW, [online], (Accessed May 28, 2024)


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Created May 14, 2014, Updated April 13, 2022