2023年6月24日发(作者：)

Chapter 5 The Link Layer and Local Area Network

1．A ( ) protocol is used to move a datagram over an individual link.

A application-layer

B transport-layer

C network-layer

D link-layer

2．The units of data exchanged by a link-layer protocol are called ( ).

A datagrams

B frames

C segments

D messages

3．Which of the following protocols is not a link-layer protocol? ( )

A Ethernet

B PPP

C HDLC

D IP

4．In the following four descriptions, which one is not correct? ( )

A link-layer protocol has the node-to-node job of moving network-layer datagrams

over a single link in the path.

B The services provided by the link-layer protocols may be different.

C A datagram must be handled by the same link-layer protocols on the different

links in the path.

D The actions taken by a link-layer protocol when sending and receiving frames

include error detection, flow control and random access.

5．Which of the following services can not offered by a link-layer protocol? ( )

A congestion control

B Link Access

C Error control

D Framing

6．( ) protocol serves to coordinate the frame transmissions of the many nodes when

multiple nodes share a single broadcast link.

A ARP

B MAC

C ICMP

D DNS

7．In the following four descriptions about the adapter, which one is not correct? ( )

A The adapter is also called as NIC.

B The adapter is a semi-autonomous unit.

C The main components of an adapter are bus interface and the link interface.

D The adapter can provide all the link-layer services.

8．Consider CRC error checking approach, the four bit generator G is 1011, and

suppose that the data D is 10101010, then the value of R is( ).

A 010

B 100 C 011

D 110

9．In the following four descriptions about random access protocol, which one is not

correct? ( )

A In slotted ALOHA, nodes can transmit at random time.

B In pure ALOHA, if a frame experiences a collision, the node will immediately

retransmit it with probability p.

C The maximum efficiency of a slotted ALOHA is higher than a pure ALOHA.

D In CSMA/CD, one node listens to the channel before transmitting.

10．In the following descriptions about MAC address, which one is not correct? ( )

A The MAC address is the address of one node’s adapter.

B No two adapters have the same MAC address.

C The MAC address doesn’t change no matter where the adapter goes.

D MAC address has a hierarchical structure.

11．The ARP protocol can translate ( ) into ( ). ( )

A host name, IP address

B host name, MAC address

C IP address, MAC address

D broadcast address, IP address

12．The value of Preamble field in Ethernet frame structure is ( )

A 10101010 10101010……10101010 11111111

B 10101011 10101011……10101011 10101011

C 10101010 10101010……10101010 10101011

D 10101010 10101010……10101010 10101010

13．There are four steps in DHCP, the DHCP server can complete ( ).

A DHCP server discovery

B DHCP server offers

C DHCP request

D DHCP response

14．In CSMA/CD, the adapter waits some time and then returns to sensing the channel.

In the following four times, which one is impossible? ( )

A 0 bit times

B 512 bit times

C 1024 bit times

D 1028 bit times

15．The most common Ethernet technologies are 10BaseT and 100BaseT. “10” and

“100” indicate( ).

A the maximum length between two adapters

B the minimum length between two adapters

C the transmission rate of the channel

D the transmission rate of the node

16．The principal components of PPP include but not( ).

A framing

B physical-control protocol C link-layer protocol

D network-layer protocol

17．In the following four options, which service can not be provided by switch? ( )

A filtering

B self-learning

C forwarding

D optimal routing

18．In the following four services, which one was be required in PPP? ( )

A packet framing

B error detection

C error correction

D multiple types of link

19．The ability to determine the interfaces to which a frame should be directed, and

then directing the frame to those interfaces is( ).

A filtering

B forwarding

C self-learning

D optimal routing

20．In ( ) transmission(s), the nodes at both ends of a link may transmit packets at

the same time.

A full-duplex

B half-duplex

C single-duplex

D both full-duplex and half-duplex

21．Consider the data D is , if use even parity checking approach, the

parity bit is( ① ), if use odd parity checking approach, the parity bit is( ② ). ( )

A ①0 ②1

B ①0 ②0

C ①1 ②1

D ①1 ②0

22．In the following four descriptions about parity checks, which one is correct? ( )

A Single-bit parity can detect all errors.

B Single-bit parity can correct one errors.

C Two-dimensional parity not only can detect a single bit error, but also can correct

that error.

D Two-dimensional parity not only can detect any combination of two errors, but

also can correct them.

23．MAC address is ( ) bits long.

A 32

B 48

C 128

D 64

24．Wireless LAN using protocol ( ).

A IEEE 802.3 B IEEE 802.4

C IEEE 802.5

D IEEE 802.11

25．The following protocols are belonging to multiple access protocols except for

( ).

A channel partitioning protocols

B routing protocols

C random access protocols

D taking-turns protocols

26．Which of the following is not belonging to channel partitioning protocols? ( )

A CSMA

B FDM

C CDMA

D TDM

27．In the following four descriptions about CSMA/CD, which one is not correct?

( )

A A node listens to the channel before transmitting.

B If someone else begins talking at the same time, stop talking.

C A transmitting node listens to the channel while it is transmitting.

D With CSMA/CD, the collisions can be avoided completely.

28．( ) provides a mechanism for nodes to translate IP addresses to link-layer

address.

A IP

B ARP

C RARP

D DNS

29．A MAC address is a ( )address.

A physical-layer

B application-layer

C link-layer

D network-layer

30．Which of the following is correct? ( )

A No two adapters have the same MAC address.

B MAC broadcast address is FF-FF-FF-FF-FF-FF.

C A portable computer with an Ethernet card always has the same MAC address, no

matter where the computer goes.

D All of the above

31．In the following four descriptions, which one is not correct? ( )

A ARP resolves an IP address to a MAC address.

B DNS resolves hostnames to IP addresses.

C DNS resolves hostnames for hosts anywhere in the Internet.

D ARP resolves IP addresses for nodes anywhere in the Internet.

32．In the LAN, ( )protocol dynamically assign IP addresses to hosts.

A DNS B ARP

C DHCP

D IP

33．DHCP protocol is a four-step process: ①DHCP request. ②DHCP ACK. ③DHCP

server discovery. ④DHCP server offer(s). The correct sequence is ( )

A ①②③④

B ③②①④

C ③④①②

D ①④③②

34．In the Ethernet frame structure, the CRC field is ( )bytes.

A 2

B 4

C 8

D 32

35．In the Ethernet frame structure, the Data field carries the ( ).

A IP datagram

B segment

C frame

D message

36．In the following four descriptions, which one is not correct? ( )

A Ethernet uses baseband transmission.

B All of the Ethernet technologies provide connection-oriented reliable service to

the network layer.

C The Ethernet 10Base2 technology uses a thin coaxial cable for the bus.

D The Ethernet 10BaseT technology uses a star topology.

37．Ethernet’s multiple access protocol is ( ).

A CDMA

B CSMA/CD

C slotted ALOHA

D token-passing protocol

38．In the following four descriptions about CSMA/CD, which one is not correct?

( )

A An adapter may begin to transmit at any time.

B An adapter never transmits a frame when it senses that some other adapter is

transmitting.

C A transmitting adapter aborts its transmission as soon as it detects that another

adapter is also transmitting.

D An adapter retransmits when it detects a collision.

39．Which of the following descriptions about CSMA/CD is correct? ( )

A No slots are used.

B It uses carrier sensing.

C It uses collision detection.

D All of the above.

40．The Ethernet 10BaseT technology uses( )as its physical media. A fiber optics

B twisted-pair copper wire

C coaxial cable

D satellite radio channel

41．For 10BaseT, the maximum length of the connection between an adapter and the

hub is ( )meters.

A 100

B 200

C 500

D 10

42．A ( )is a physical-layer device that acts on individual bits rather than on frames.

A switch

B hub

C router

D gateway

43．A hub is a ( )device that acts on individual bits rather than on frames.

A physical-layer

B link-layer

C network-layer

D ransport-layer

44．A switch is a( )device that acts on frame.

A physical-layer

B link-layer

C network-layer

D transport-layer

45．In the following four descriptions, which one is not correct? ( )

A Switches can interconnect different LAN technologies.

B Hubs can interconnect different LAN technologies.

C There is no limit to how large a LAN can be when switches are used to

interconnect LAN segments.

D There is restriction on the maximum allowable number of nodes in a collision

domain when hubs are used to interconnect LAN segments.

46．The ability to determine whether a frame should be forwarded to some interface or

should just be dropped is ( ).

A filtering

B forwarding

C self-learning

D optimal routing

47．Which of the following devices is not a plug and play device? ( )

A hub

B router

C switch

D repeater

48．Which of the following devices is not cut-through device? ( ) A hub

B router

C switch

D repeater

49．In the following four descriptions, which one is not correct? ( )

A Switches do not offer any protection against broadcast storms.

B Routers provide firewall protection against layer-2 broadcast storms.

C Both switches and routers are plug and play devices.

D A router is a layer-3 packet switch, a switch is a layer-2 packet switch.

50．Which device has the same collision domain? ( )

A Hub

B Switch

C Router

D Bridge

51．IEEE802.2 protocol belong to ( )layer

A network

B MAC

C LLC

D physical

52．IEEE802.11 protocol defines ( )rules.

A Ethernet Bus

B wireless WAN

C wireless LAN

D Token Bus

53．In data link-layer, which protocol is used to share bandwidth? ( )

A SMTP

B ICMP

C ARP

D CSMA/CD

54．When two or more nodes on the LAN segments transmit at the same time, there

will be a collision and all of the transmitting nodes well enter exponential back-off,

that is all of the LAN segments belong to the same( ).

A collision domain

B switch

C bridge

D hub

55．( )allows different nodes to transmit simultaneously and yet have their respective

receivers correctly receive a sender’s encoded data bits.

A CDMA

B CSMA

C CSMA/CD

D CSMA/CA

56．Because there are both network-layer addresses (for example, Internet IP

addresses) and link-layer addresses (that is, LAN addresses), there is a need to translate between them. For the Internet, this is the job of ( ).

A RIP

B OSPF

C ARP

D IP

57．PPP defines a special control escape byte, ( ). If the flag sequence, 01111110

appears anywhere in the frame, except in the flag field, PPP precedes that instance of

the flag pattern with the control escape byte.

A 01111110

B 01111101

C 10011001

D 10111110

58．The device ( ) can isolate collision domains for each of the LAN segment.

A modem

B switch

C hub

D NIC

59．In the following four descriptions about PPP, which one is not correct? ( )

A PPP is required to detect and correct errors.

B PPP is not required to deliver frames to the link receiver in the same order in

which they were sent by the link sender.

C PPP need only operate over links that have a single sender and a single receiver.

D PPP is not required to provide flow control.

60．In the PPP data frame, the( ) field tells the PPP receivers the upper-layer

protocol to which the received encapsulated data belongs.

A flag

B control

C protocol

D checksum

61．PPP’s link-control protocols (LCP) accomplish ( ).

A initializing the PPP link

B maintaining the PPP link

C taking down the PPP link

D all of the above

62．The PPP link always begins in the ( ) state and ends in the ( ) state. ( )

A open, terminating

B open, dead

C dead, dead

D dead, terminating

63．For( ) links that have a single sender at one end of the link and a single receiver

at the other end of the link.

A point-to-point

B broadcast

C multicast D all of the above

64．With ( )transmission, the nodes at both ends of a link may transmit packets at the

same time.

A half-duplex

B full-duplex

C simplex(单工)

D synchronous

65．With ( ) transmission, a node can not both transmit and receive at the same time.

A half-duplex

B full-duplex

C simplex(单工)

D synchronous

66．Which of the following functions can’t be implemented in the NIC? ( )

A encapsulation and decapsulation

B error detection

C multiple access protocol

D routing

67．Which of the following four descriptions is wrong? ( )

A The bus interface of an adapter is responsible for communication with the

adapter’s parent node.

B The link interface of an adapter is responsible for implementing the link-layer

protocol.

C The bus interface may provide error detection, random access functions.

D The main components of an adapter are the bus interface and the link interface.

68．For odd parity schemes, which of the following is correct? ( )

A 011010001

B 111000110

C 110101110

D 000110110

69．( )divides time into time frames and further divides each time frame into N time

slots.

A FDM

B TMD

C CDMA

D CSMA

70．With CDMA, each node is assigned a different ( )

A code

B time slot

C frequency

D link

71．Which of the following four descriptions about random access protocol is not

correct? ( )

A A transmission node transmits at the full rate of the channel

B When a collision happens, each node involved in the collision retransmits at once. C Both slotted ALOHA and CSMA/CD are random access protocols.

D With random access protocol, there may be empty slots.

72．PPP defines a special control escape byte 01111101. If the data is

b1b201111110b3b4b5, the value is( )after byte stuffing.

A b1b21110b3b4b5

B b1b21101b3b4b5

C b5b4b31101b2b1

D b5b4b31110b2b1

73．MAC address is in ( ) of the computer.

A RAM

B NIC

C hard disk

D cache

74．Which of the following is wrong? ( )

A ARP table is configured by a system administrator

B ARP table is built automatically

C ARP table is dynamic

D ARP table maps IP addresses to MAC addresses

75．NIC works in ( )layer.

A physical

B link

C network

D transport

76．In LAN, if UTP is used, the common connector is( ).

A AUI

B BNC

C RJ-45

D NNI

77．The modem’s function(s) is(are) ( ).

A translates digital signal into analog signal

B translates analog signal into digital signal

C both translates analog signal into digital signal and translates digital signal into

analog signal

D translates one kind of digital signal into another digital signal

78．( )defines Token-Ring protocol.

A IEEE 802.3

B IEEE 802.4

C IEEE 802.5

D IEEE 802.2

79．( )defines Token-Bus protocol.

A IEEE 802.3

B IEEE 802.4

C IEEE 802.5

D IEEE 802.2 80．( ) defines CSMA/CD protocol.

A IEEE 802.3

B IEEE 802.4

C IEEE 802.5

D IEEE 802.2

81．The computer network that concentrated in a geographical area, such as in a

building or on a university campus, is ( )

A a LAN

B a MAN

C a WAN

D the Internet

82．The MAC address is ( ) bits long.

A 32

B 48

C 128

D 256

83．Which of the following four descriptions about MAC addresses is wrong? ( )

A a MAC address is burned into the adapter’s ROM

B No two adapters have the same address

C An adapter’s MAC address is dynamic

D A MAC address is a link-layer address

84．Which of the following four descriptions about DHCP is correct? ( )

A DHCP is C/S architecture

B DHCP uses TCP as its underlying transport protocol

C The IP address offered by a DHCP server is valid forever

D The DHCP server will offer the same IP address to a host when the host requests

an IP address

85． The ( )field permits Ethernet to multiplex network-layer protocols.

A preamble

B type

C CRC

D destination MAC address

86．For 10BaseT, the maximum length of the connection between an adapter and the

hub is ( ) meters.

A 50

B 100

C 200

D 500

87．An entry in the switch table contains the following information excepts for ( )

A the MAC address of a node

B the switch interface that leads towards the node

C the time at which the entry for the node was placed in the table

D the IP address of a node 88．Consider the 4-bit generator , G is 1001, and suppose that D has the value

101110000. What is the value of R?

89．Consider the following graph of the network. Suppose Host A will send a

datagram to Host B, Host A run OICQ on port 4000, Host B run OICQ on port 8000.

All of ARP tables are up to date. Enumerate all the steps when message “Hello” is

sent from host A to host B.