Patent ID: 6618455
Filing Date: 2003-09-09
Classification: H04J

Abstract:
A clock management method for a synchronous network system including a plurality of transmission apparatuses, each of said transmission apparatuses selecting a master clock signal from a plurality of clock signals and carrying out the communication with the other of said transmission apparatuses using a clock signal generated based on said master clock signal or using a clock signal generated in the transmission apparatus, comprising the steps of:selectively switching and outputting said master clock signal by a clock switching unit based on quality information transferred together with a plurality of said clock signals; setting a variable threshold for quality level deterioration determination based on said quality information; and issuing an alarm when the quality level of the clock signal selectively switched and output by said clock switching unit is deteriorated to such an extent as to exceed said threshold; wherein said plurality of transmission apparatuses includes a plurality of types of units; and said method further comprises the step of identifying the type of a unit and selectively outputting a clock signal of a type corresponding to the type of said unit.