How do I configure 1+1 linear MSP on the OSN 3500

Dear friend!
It is recommended that the working and protection channels of the linear MSP be configured on different boards. On the OptiX OSN 3500, the working channel is 7-SLQ4-3, and the protection channel is the STM-4 port of another board, for example, the board in slot 12.
Thank you!

HI
adding to what Mr Liqiang said , I think you should know these Ideas:-
1- when you choose 1+1 msp you cant use the protection link for sending traffic .
2- you should try use fiber cable in main link different than the fiber cable used for standby link .
3- you should know the meaning of the choice single ended/dual ended switching
Single-Ended Switching
means that the switch will happen in the RX side only .
Dual-Ended Switching
means that the switch will happen in the RX and TX sides.

 dear

you can follow and check the remarks in the below picture