When setting the monitoring time of network element performance events, which of the following should be set as the time?

When configuring LMSP, there are two switching modes: single-ended switching and double-ended switching. Single-ended switching does not require protection protocols to be enabled.

The refractive index n1 of the fiber core () the cladding refractive index n2, which is a necessary condition for the transmission of optical signals in the optical fiber?

Among the following boards, whether the protection is configured or not, which options will interrupt the services passing through the board if the board is replaced? (Multiple choice)

Which of the following are the disadvantages of traditional OTDR instruments when measuring optical fibers? (Multiple choice)