When 172.17.15.0/24 is subnetted using an extra 4 bits, which of the following addresses are legal subnet addresses? (Multiple choice)

The unprotected chain consists of four network elements: NE1, NE2, NE3, and NE4. An end-to-end VC4 path NE1-NE4 is created, and NE5 is added between NE2 and NE3 for capacity expansion. The original configuration remains unchanged, and no service is configured on NE5. In this case, the unprotected chain becomes NE1-NE2-NE5-NE3-NE4. How many VC4 paths can be searched out?

In an MSP ring, in which multiplex section states can a network element migrate? (Multiple choice)

Which of the following is the electrical layer cost of OTN? (Multiple choice).

Which of the following is the protection method of TPS?