Hello, everyone!
In this post, I'll continue to share OTN basics with you.
Network level protection schemes + protection function + how switching process works.
On end to end network, protection is provided forservice access side devices and OTN devices on transport networks ensuring high network reliability and improving the device disaster recovery ability.
OTN network level protection schemes employ the dual feeding and selective receiving technology.
Dual feeding: two signals are sent from the source end and transmitted over two paths simultaneously
Selective receiving: allows only one of the signals with better quality to be received at the receive end after comparing the signals on the two paths
Switch types:
Non-revertive mode (services are still received from the protection path even after the fault on the working path is resolved)
Revertive mode (services are received from the working path after the fault on the working path is resolved)
OTN system provides comprehensive network-level protection schemes to meet the reliability at each layer of the OTN network
1+1 OTS optical line protection: protects the fibers between two adjacent OLA sites
1+1 OMS optical line protection: provides protection for OLA sites in addition to the protection for optical fibers
Intra-board1+1 Protection: line-side protection that protects the OCh service on single channels and optical-layer boards such as multiplexer/demultiplexer boards and boards at OLA sites
Clientside 1+1 Protection: that implements end to end protection services on the entire OTN network and protect both fibers and OTN devices
Tributary SNCP protection: tributary side protection that protects the two service sources on the client and the tributary boards
ODUk SNCP protection provide protection forsmaller granularity ODUk services, and devices such as line boards, multiplex/demultiplexerboards, OA boards, WSS boards and boards at OLA sites. 
SW SNCP is similar with ODUk SNCP, this protection protects GE and Any services
More information:
That's all, I hope you like it.
Thank you!
