A and C are WDM OTM sites, and B is a regeneration site. If the ODU2_LCK signal is inserted at site A, which of the following statements are correct?

Which step is more when the the single board replacement operation of main control board single configuration than main control board double configuration?

For an MSTP device, the service layer path is a path existing on the network management side, and the client layer path is a path existing on the network element side.

The overhead ratio is a factor that affects the error correction capability of FEC technology. Generally, under the same FEC encoding/decoding algorithm, the higher the overhead ratio, the greater the net coding benefit.

Which of the following are not part of the 400G originating modulation technology?