1588透传中晶振引入误差的一种改进方法

Method to Reduce Error of IEEE1588 Transparent Clock Caused by Crystal Ocsillator

晶振的精度是引起网络设备时钟透传误差的最主要原因;通过对IEEE1588v2P2P透传定时过程的分析,发现当仅考虑晶振因素时,透传定时误差正比于定时报文在网络设备内的处理时间;这为减小晶振对透传时钟精度的影响提供了一种简单有效的方法,即缩短定时报文在网络设备内处理时间;缩短该处理时间的具体办法被给出;通过实际设备验证,改进后的定时报文处理时间可以比常规方法减少两到三个量级,相应地可以推导出晶振对定时精度的影响也降低了两到三个量级。

crystal oscillator＇s uncertainty in a network equipement is the major cause of the 1588 tranparent clock inacuracy. Based on the analysis of the 1588 p2p transparent clocking process, it is found that the inaeuraey is proportional to the duration that the 1588 packet is pro- eessed within the equipement, when only oesillator＇s uncertainty is considered. The specific improving implementation to reduce the process ing time was proposed and the validation of these implementation in a real network equipment shows the proposed method can reduce the pro- cessing time 2--3 orders compared to that without the improvement.