时钟标记在SDH同步网络中的设置方法  

Setting method of clock tag in SDH network

作　　者：成俊明[1] 韩际晖[1] 

机构地区：[1]江苏省电力公司通信中心,江苏南京210024

出　　处：《电力系统通信》2007年第B06期51-53,共3页Telecommunications for Electric Power System

摘　　要：时钟标记SSM在SDH帧结构中用于传输同步状态信息,是SDH网元选择同步时钟源的唯一依据。不正确的时钟标记设置将导致网元无法同步于最高质量的时钟源,或在时钟源故障时网元无法正确地进行时钟切换,降低了SDH传输网的同步性能。文章分析了在SDH传输网络中SSM字节的基本算法,并通过实例说明了SSM在实际应用中需要注意的问题。SSM clock tag is used in SDH frame structure to transmit synchronous Status Message. It is the only foundation for SDH network elements to select synchronal clock source. Setting clock tag incorrectly will cause some problems, such as, network elements can not synchronize with the best clock source or incorrectly switch clock when clock source fault occurs. All of these will degrade the synchronal per- formance in SDH network. The paper analyzes basic algorithm of SSM byte in SDH network and illustrates some problems in SSM application with an example which should be noticed in practice.

关 键 词：同步状态消息 同步数字系列 同步时钟 

分 类 号：TN915.01[电子电信—通信与信息系统]