蔚睹

protection和restoration的区别：
The term protection is used to denote the paradigm whereby a dedicated backup resource is deployed to recover the services provided by a failed resource. In contrast, the term restoration is used to denote the paradigm whereby backup resources are not dedicated to specific primary resources, but a pool of resources is kept available for overall recovery purposes.

Linear Protection——线路段保护
1:N双向保护：

1：N虚拟子网连接保护

UPSR——单向通道交换环保护