大学MOOC 计算机网络(厦门大学)1450585164 最新慕课完整章节测试答案
一、物理层
第01课 传输介质
1、单选题：
To reduce the interference caused by random electromagnetic radiation, communication systems DO NOT use ______.
选项：
A: twisted pair wiring
B: parallel pair wiring
C: coaxial cable
D: none of above
答案: 【 parallel pair wiring】
2、单选题：
In a factory that uses electric arc welding equipment, ______ is the best wiring for short-distance communication.
选项：
A: unshielded twisted pair
B: shielded twisted pair
C: coaxial cable
D: optical fibers
答案: 【 coaxial cable】
3、单选题：
RJ-45 network cable with which we connect two computers uses ____ cable.
选项：
A: parallel-pair
B: twisted-pair
C: coaxial
D: fiber-optic
答案: 【 twisted-pair】
4、单选题：
To reduce the interference caused by random electromagnetic radiation, communication systems DO NOT use ____________.
选项：
A: twisted pair wiring
B: parallel pair wiring
C: coaxial cable
D: none of the others
答案: 【 parallel pair wiring】
第02课 局域异步通信
1、单选题：
Which way is used during the communication by RS-232 DB9?
选项：
A: simplex transmission
B: half-duplex transmission
C: full duplex transmission
D: none
答案: 【 full duplex transmission】
2、单选题：
The RS-232 standard sends each bit of the character, and follows each character with an idle period ______ bit(s) long.
选项：
A: no
B: one
C: at least one
D: at most one
答案: 【 at least one】
3、单选题：
Which of the following about RS-232-C is correct?
选项：
A: RS-232-C specifies that a sender transmits a start bit before transmitting the bits of a character, and a stop bit is appended to each character.
B: When it finishes transmission, the sender leaves the wire with a positive voltage until another character is ready for transmission.
C: RS-232-C uses voltage ranging from -5 volts to +5 volts.
D: Negative voltage corresponds to logical 0, while positive voltage corresponds to logical 1.
答案: 【 RS-232-C specifies that a sender transmits a start bit before transmitting the bits of a character, and a stop bit is appended to each character.】
4、填空题：
_________串行传输类型适合于视频传输。（填一种类型，2个字）
答案: 【 同步】
5、填空题：
_________串行传输适合计算机键盘连接。（填一种类型，2个字）
答案: 【 异步】
6、填空题：
假定用38,400 baud波特率的RS-232方式发送了10000个7位字符，则传输需要________秒。（每个字符都有1个起始位和1个终止位）
答案: 【 2.34##%_YZPRLFH_%##2.344##%_YZPRLFH_%##2.3438##%_YZPRLFH_%##2.34375】
第03课 远距离传输
1、单选题：
_____ division modulation can transmit electromagnetic signals simultaneously without interference provided they each use a separate channel.
选项：
A: Frequency
B: Wave
C: Time
D: Code
答案: 【 Frequency】
2、单选题：
China Unicom and China Telecom received their 4G standard license FDD-LTE in Feb. 2015. The principle of ______ division duplex is similar to FDD.
选项：
A: code
B: space
C: time
D: wave
答案: 【 wave】
3、单选题：
By eliminating unused slots, ____ TDM takes less time to send the same amount of data.
选项：
A: hierarchical
B: normal
C: statistical
D: synchronous
答案: 【 statistical】
4、单选题：
By Shannon Theorem, faster transmission speeds will only be possible if the ______ can be improved.
选项：
A: signal-to-noise ratio
B: topology
C: signal intensity
D: noise intensity
答案: 【 signal-to-noise ratio】
5、单选题：
Nyquist Theorem tells a theoretical bound on the maximum rate is related to ______.
选项：
A: baud rate
B: coding error
C: signal intensity
D: noise intensity
答案: 【 baud rate】
6、判断题：
频分复用只能配合载波调频使用。
选项：
A: 正确
B: 错误
答案: 【 错误】
7、判断题：
RJ-45网线属于远程通信技术，而不是局域通信技术。
选项：
A: 正确
B: 错误
答案: 【 错误】
三、网络层
第10课 IP编址和报文
1、单选题：
Which is a valid source address in an IP datagram?
选项：
A: 0.0.0.0
B: 127.0.0.0
C: 128.0.0.0
D: 255.255.255.255
答案: 【 0.0.0.0】
2、单选题：
Which of the following fields is NOT valid in the IPv4 datagram header?
选项：
A: Source IP
B: Source port
C: Version
D: Header checksum
答案: 【 Source port】
3、单选题：
The field _____ is NOT existed in both Ethernet and IP headers.
选项：
A: Source Address
B: Type
C: Check Code
D: Header Length
答案: 【 Header Length】
4、单选题：
Which of following problems needs to be considered in the data link layer?
选项：
A: Bit encoding and decoding.
B: Error control.
C: Datagram fragmentation.
D: Out of order receipt of packets.
答案: 【 Error control.】
5、单选题：
The mask ________ is assigned to a subnet 218.193.0.0/27.
选项：
A: 255.255.255.224
B: 31.255.255.255
C: 255.255.0.0
D: 218.193.0.31
答案: 【 255.255.255.224】
6、单选题：
Which of the following statements about WAN store and forward is TRUE?
选项：
A: A system that uses the store and forward paradigm can keep each data link busy, and thus, decrease overall performance.
B: The forward operation occurs when a packet arrives: I/O hardware inside the packet switch places a copy of the packet in memory.
C: The store operation occurs once a packet has arrived and is waiting in memory.
D: The processor examines the packet, determines its destination, and sends the packet over the I/O interface that leads to the destination.
答案: 【 The processor examines the packet, determines its destination, and sends the packet over the I/O interface that leads to the destination.】
7、单选题：
A ____ can connect two LANs, a LAN and a WAN, or two WANs.
选项：
A: repeater
B: bridge
C: switch
D: router
答案: 【 router】
8、单选题：
When a host starts up and requests an IP addresses, _____ must be used.
选项：
A: unicast
B: multicast
C: broadcast
D: none of the others
答案: 【 broadcast