The fiber core refractive index n1 must be ( ) the cladding layer refractive index n2, which is a necessary condition for transmitting optical signals in optical fibers.

• A.higher than
• B.lower than
• C.equal to

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A MAC address consists of 48 bits and is globally unique. Which of the following is the meaning of the MAC address whose eighth bit is 1?

• A.Multicast address
• B.Unicast address
• C.Bicast address
• D.Broadcast address

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The pointer is used for alignment and indicates the start position of VC-n in the corresponding AU or TU frame. In this way, the receive end can correctly remove the corresponding VC from the STM-N, and then split the VC and C encapsulation to separate low-rate signals, such as PDH. That is, low-rate tributary signals can be directly dropped from the STM-N signal.

• A.FALSE
• B.TRUE

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Which of the following are basic functions of the U2000? (Multiple Choice)

• A.Topology management
• B.Alarm management
• C.Performance management
• D.Security management

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Which of the following statements about the optical-layer interfaces OTM-n.m and OTM-nr.m of OTN is incorrect?

• A.n indicates the number of wavelengths carried by the maximum capacity.
• B.r indicates OTM without the OSC function.
• C.OTM-nr.m with OSC signals is OTM-n.m.
• D.m indicates the rate. The value can be 1, 2, or 3.

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