Open AccessMeasurement Scheme for One‐Way Delay Variation with Detection and Removal of Clock Skew
Author(s) -
Aoki Makoto,
Oki Eiji,
RojasCessa Roberto
Publication year - 2010
Publication title -
etri journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.295
H-Index - 46
eISSN - 2233-7326
pISSN - 1225-6463
DOI - 10.4218/etrij.10.0109.0611
Subject(s) - clock synchronization , clock skew , computer science , clock drift , synchronization (alternating current) , real time computing , timing failure , global positioning system , digital clock manager , network time protocol , skew , clock domain crossing , self clocking signal , network packet , jitter , computer network , time synchronization , synchronous circuit , clock signal , telecommunications , channel (broadcasting)
One‐way delay variation (OWDV) has become increasingly of interest to researchers as a way to evaluate network state and service quality, especially for real‐time and streaming services such as voice‐over‐Internet‐protocol (VoIP) and video. Many schemes for OWDV measurement require clock synchronization through the global‐positioning system (GPS) or network time protocol. In clock‐synchronized approaches, the accuracy of OWDV measurement depends on the accuracy of the clock synchronization. GPS provides highly accurate clock synchronization. However, the deployment of GPS on legacy network equipment might be slow and costly. This paper proposes a method for measuring OWDV that dispenses with clock synchronization. The clock synchronization problem is mainly caused by clock skew. The proposed approach is based on the measurement of inter‐packet delay and accumulated OWDV. This paper shows the performance of the proposed scheme via simulations and through experiments in a VoIP network. The presented simulation and measurement results indicate that clock skew can be efficiently measured and removed and that OWDV can be measured without requiring clock synchronization.