The protection switching in SDH networks is, in general, implemented using DXC and ADM equipment. Three methods, i.e. manual configuration, previously provisioned routing table and dynamic route calculation, are used for selecting the protection routes.

• SDH网中的保护倒换功能通常利用交叉连接设备（DXC）和分插复用设备（ADM）来完成，保护路由的选择有三种常用的方法，即手工配置、依靠预先存放的路由表和动态路由计算。