| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To improve reliability as timing source protection. <P>SOLUTION: A fault detecting section 31 detects a fault state of timing master clock from a timing master, and notifies a timing source control section 41 of the detection information. The timing source control section 41 determines an SSM value to be transmitted to each line on the basis of a table, and determines to notify an SSM transmitting section of each line of the SSM value and synchronize with which timing source in each line. When two or more SDH lines are connected between transmission communication devices and they are used as timing sources, timing sources can be switched without forming a timing group by setting a DNU group in each line. Consequently, since two or more SDH lines can be used as timing source lines, it is possible to improve reliability as timing source protection. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
