Data Communications Farozen Bits - 1

CHAPTER-1

INTRODUCTION OF DATA COMMUNICATIONS AND NETWORKING

1. There are ______________ Internet service providers. A) regional B) local C) national and international D) all of the above

2. ______ refers to the physical or logical arrangement of a network. A) Topology B) Mode of operation C) Data flow D) None of the above

3. A ______ is a data communication system spanning states, countries, or the whole world. A) MAN B) WAN C) LAN D) none of the above

4. A _______ connection provides a dedicated link between two devices. A) primary B) multipoint C) point-to-point D) secondary

5. Which topology requires a multipoint connection? A) Bus B) Star C) Mesh D) Ring

6. A ________ is a set of rules that governs data communication. A) protocol B) forum C) standard D) none of the above

7. In a ______ connection, two and only two devices are connected by a dedicated link. A) multipoint B) point-to-point C) (a) and (b) D) none of the above

8. The information to be communicated in a data communications system is the _______. A) Medium B) Protocol C) Message D) Transmission

9. ________ defines how a particular pattern to be interpreted, and what action is to be taken based on that interpretation.

A) Syntax B) Semantics C) Timing D) None of the above

10. Frequency of failure and network recovery time after a failure are measures of the _______of a network.

A) Performance B) Security C) Reliability D) Feasibility

11. A television broadcast is an example of _______ transmission. A) half-duplex B) simplex C) full-duplex D) automatic

12. Data flow between two devices can occur in a _______ way. A) simplex B) half-duplex C) full-duplex D) all of the above

13. _______ are special-interest groups that quickly test, evaluate, and standardize new technologies.

A) Standards organizations B) Regulatory agencies C) Forums D) All of the above

14. Which agency developed standards for physical connection interfaces and electronic signaling specifications?

A) ISO B) ITU-T C) ANSI D) EIA

15. A _______ is a data communication system within a building, plant, or campus, or between nearby buildings.

A) LAN B) MAN C) WAN D) none of the above

16. _______ refers to two characteristics: when data should be sent and how fast it can be sent. A) Semantics B) Timing C) Syntax D) none of the above

17. This was the first network. A) CSNET B) NSFNET C) ARPANET D) ANSNET

18. Devices may be arranged in a _____ topology. A) mesh B) ring C) bus D) all of the above

19. _______ is the protocol suite for the current Internet. A) UNIX B) NCP C) TCP/IP D) ACM

20. ________ is a collection of many separate networks. A) A WAN B) An internet C) A LAN D) None of the above

21. In a ________ connection, three or more devices share a link. A) point-to-point B) multipoint C) (a) and (b) D) none of the above

22. Which organization has authority over interstate and international commerce in the communications field?

A) FCC B) IEEE C) ITU-T D) ISOC

23. In the original ARPANET, _______ were directly connected together. A) routers B) host computers C) networks D) IMPs

24. Communication between a computer and a keyboard involves ______________ transmission.

A) simplex B) half-duplex C) full-duplex D) automatic

25. Which topology requires a central controller or hub? A) Mesh B) Bus C) Star D) Ring

26. The _______ is the physical path over which a message travels. A) Protocol B) Signal C) Medium D) All the above

27. In a _______ connection, more than two devices can share a single link. A) multipoint B) point-to-point C) primary D) secondary

28. _______ refers to the structure or format of the data, meaning the order in which they are presented.

A) Semantics B) Syntax C) Timing D) All of the above

29. An unauthorized user is a network _______ issue. A) Security B) Reliability

C) Performance D) All the above

30. ________ is an idea or concept that is a precursor to an Internet standard. A) RCF B) ID C) RFC D) none of the above

31. In _______ transmission, the channel capacity is shared by both communicating devices at all times.

A) simplex B) half-duplex C) full-duplex D) half-simplex

CHAPTER-2

NETWORK MODELS

1. The ______ layer adds a header to the packet coming from the upper layer that includes the logical addresses of the sender and receiver.

A) data link B) network C) physical D) none of the above

2. Which of the following is an application layer service? A) File transfer and access B) Mail service C) Remote log-in D) All the above

3. When data are transmitted from device A to device B, the header from A's layer 4 is read by B's _______ layer.

A) Transport B) Application C) Physical D) None of the above

4. __________ provides full transport layer services to applications. A) UDP B) TCP C) ARP D) none of the above

5. The process-to-process delivery of the entire message is the responsibility of the _______ layer.

A) Transport B) Application C) Physical D) Network

6. The ______ layer is responsible for moving frames from one hop (node) to the next. A) transport B) data link C) physical D) none of the above

7. The _______ layer is responsible for delivering data units from one station to the next without errors.

A) physical B) data link C) transport D) network

8. The session, presentation, and application layers are the ____ support layers. A) user B) network C) both (a) and (b) D) neither (a) nor (b)

9. The physical, data link, and network layers are the ______ support layers. A) network B) user C) both (a) and (b) D) neither (a) nor (b)

10. The ________ layer is responsible for the process-to-process delivery of the entire message. A) transport B) physical C) network D) data link

11. The _______ layer lies between the network layer and the application layer. A) Data link B) Transport C) Physical D) None of the above

12. The Internetworking Protocol (IP) is a ________ protocol. A) connection-oriented B) reliable C) both a and b D) none of the above

13. The _______ layer links the network support layers and the user support layers. A) session B) transport C) data link D) network

14. ICMPv6 includes _______. A) IGMP B) ARP

C) RARP D) a and b

15. The ____ address uniquely defines a host on the Internet. A) IP B) port C) specific D) physical

16. The _______ layer coordinates the functions required to transmit a bit stream over a physical medium.

A) data link B) transport C) network D) physical

17. The ______ layer is responsible for the source-to-destination delivery of a packet across multiple network links.

A) network B) physical C) data link D) transport

18. Mail services are available to network users through the _______ layer. A) Transport B) Physical C) Data link D) Application

19. The ____ created a model called the Open Systems Interconnection, which allows diverse systems to communicate.

A) IEEE B) ISO C) OSI D) none of the above

20. The _______ layer changes bits into electromagnetic signals. A) Physical B) Transport C) Data link D) None of the above

21. IPv6 has _______ -bit addresses. A) 128 B) 32 C) 64 D) variable

22. The_____ address identifies a process on a host. A) specific B) port C) IP D) physical

23. The_________ layer is responsible for the delivery of a message from one process to another.

A) transport B) network C) physical

D) none of the above 24. The _________ layer enables the users to access the network.

A) application B) physical C) data link D) transport

25. The TCP/IP _______ layer is equivalent to the combined session, presentation, and application layers of the OSI model.

A) data link B) network C) physical D) application

26. When a host on network A sends a message to a host on network B, which address does the router look at?

A) logical B) physical C) port D) none of the above

27. As the data packet moves from the upper to the lower layers, headers are _______. A) Rearranged B) Removed C) Added D) Modified

28. The physical layer is concerned with the movement of _______ over the physical medium. A) dialogs B) protocols C) bits D) programs

29. To deliver a message to the correct application program running on a host, the _______ address must be consulted.

A) physical B) port C) IP D) none of the above

30. Ethernet uses a ______ physical address that is imprinted on the network interface card (NIC).

A) 32-bit B) 6-byte C) 64-bit D) none of the above

31. The _______ layer is the layer closest to the transmission medium. A) Network B) Transport C) Physical D) Data link

32. The OSI model consists of _______ layers. A) eight B) seven C) five D) three

33. The ________ address, also known as the link address, is the address of a node as defined by its LAN or WAN.

A) IP B) port C) specific D) physical

34. Layer 2 lies between the physical layer and the _______ layer. A) Data link B) Transport C) Network D) None of the above

35. Why was the OSI model developed? A) The rate of data transfer was increasing exponentially B) Standards were needed to allow any two systems to communicate C) Manufacturers disliked the TCP/IP protocol suite. D) None of the above

36. In the OSI model, as a data packet moves from the lower to the upper layers, headers are _______.

A) removed B) added C) rearranged D) modified

37. In the OSI model, when data is transmitted from device A to device B, the header from A's layer 5 is read by B's _______ layer.

A) session B) physical C) transport D) presentation

38. The seven-layer _____ model provides guidelines for the development of universally compatible networking protocols.

A) ISO B) OSI C) IEEE D) none of the above

39. The Internet model consists of _______ layers. A) Eight B) Seven C) Five D) Three

40. In the OSI model, what is the main function of the transport layer? A) process-to-process message delivery B) node-to-node delivery C) synchronization D) updating and maintenance of routing tables

41. _______ is a process-to-process protocol that adds only port addresses, checksum error control, and length information to the data from the upper layer.

A) IP B) TCP C) UDP D) none of the above

42. The ______ layer establishes, maintains, and synchronizes the interactions between communicating devices.

A) session B) physical C) transport D) network

43. A port address in TCP/IP is ______ bits long. A) 16 B) 32 C) 48 D) none of the above

44. In the OSI model, encryption and decryption are functions of the ________ layer. A) application B) presentation C) session D) transport

45. TCP/IP is a ______ hierarchical protocol suite developed ____ the OSI model. A) five-layer; before B) six-layer; before C) seven-layer; before D) five-layer; after

46. The ________ address, also known as the link address, is the address of a node as defined by its LAN or WAN.

A) logical B) port C) physical D) none of the above

47. The _______ model shows how the network functions of a computer ought to be organized. A) ANSI B) CCITT C) ISO D) OSI

48. The _______ layer ensures interoperability between communicating devices through transformation of data into a mutually agreed upon format.

A) network B) presentation C) transport D) data link

CHAPTER-3

DATA AND SIGNALS

1. If the maximum amplitude of a sine wave is 2 V, the minimum amplitude is ______V. A) 2 B) 1 C) -2 D) between -2 and 2

2. _________ can impair a signal. A) Noise B) Attenuation C) Distortion D) All of the above

3. ________is the rate of change with respect to time. A) Time B) Frequency C) Amplitude D) Voltage

4. A signal is measured at two different points. The power is P1 at the first point and P2 at the second point. The dB is 0. This means ________.

A) P2 equals P1 B) P2 is zero C) P2 is much larger than P1 D) P2 is much smaller than P1

5. Baseband transmission of a digital signal is possible only if we have a ____ channel. A) bandpass B) low-pass C) high rate D) low rate

6. ________ is a type of transmission impairment in which the signal loses strength due to the resistance of the transmission medium.

A) Distortion B) Attenuation C) Noise D) Decibel

7. A sine wave in the ______ domain can be represented by one single spike in the _____ domain.

A) time; phase B) frequency; time C) time; frequency D) phase; time

8. If the bandwidth of a signal is 5 KHz and the lowest frequency is 52 KHz, what is the highest frequency?

A) 5 KHz B) 47 KHz C) 57 KHz D) 10 KHz

9. In a time-domain plot, the horizontal axis is a measure of ________. A) phase B) signal amplitude C) frequency D) time

10. _______ data are continuous and take continuous values. A) digital B) analog C) (a) or (b) D) none of the above

11. Frequency and period are ______. A) proportional to each other B) inverse of each other C) the same D) none of the above

12. When propagation speed is multiplied by propagation time, we get the ________. A) wavelength of the signal B) throughput C) distance a signal or bit has traveled D) distortion factor

13. A _________ sine wave is not useful in data communications; we need to send a _______ signal.

A) single-frequency; composite B) composite; single-frequency This is the correct answer. C) single-frequency; double-frequency D) none of the above

14. The _________ product defines the number of bits that can fill the link. A) delay-amplitude B) frequency-amplitude C) bandwidth-period D) bandwidth-delay

15. _______ signals can have only a limited number of values. A) Digital B) Analog C) (a) or (b) D) None of the above

16. Before data can be transmitted, they must be transformed to ________. A) periodic signals B) electromagnetic signals C) aperiodic signals D) low-frequency sine waves

17. Data can be ________. A) digital B) analog C) (a) or (b) D) none of the above

18. ________ is a type of transmission impairment in which the signal loses strength due to the different propagation speeds of each frequency that makes up the signal.

A) Noise B) Distortion

C) Attenuation D) Decibel

19. Signals can be ________. A) digital B) analog C) either (a) or (b) D) neither (a) nor (b)

20. A sine wave is ________. A) periodic and discrete B) aperiodic and discrete C) periodic and continuous D) aperiodic and continuous

21. _______ data have discrete states and take discrete values. A) Analog B) Digital C) (a) or (b) D) None of the above

22. For a ______ channel, we need to use the Shannon capacity to find the maximum bit rate. A) noiseless B) noisy C) low-pass D) bandpass

23. What is the bandwidth of a signal that ranges from 1 MHz to 4 MHz? A) 1 KHz B) 3 MHz C) 4 MHz D) none of the above

24. _____ signals can have an infinite number of values in a range. A) Analog B) Digital C) (a) or (b) D) None of the above

25. A(n)_________ signal is a composite analog signal with an infinite bandwidth. A) digital B) analog C) either (a) or (b) D) neither (a) nor (b)

26. A periodic signal completes one cycle in 0.001 s. What is the frequency? A) 1 Hz B) 100 Hz C) 1 KHz D) 1 MHz

27. The _____ of a composite signal is the difference between the highest and the lowest frequencies contained in that signal.

A) period B) bandwidth C) frequency D) amplitude

28. ________ is a type of transmission impairment in which an outside source such as crosstalk corrupts a signal.

A) Noise B) Distortion C) Attenuation D) Decibel

29. _______ describes the position of the waveform relative to time 0. A) Amplitude B) Phase C) Frequency D) Voltage

30. Given two sine waves A and B, if the frequency of A is twice that of B, then the period of B is ________ that of A.

A) one-half B) twice C) the same as D) indeterminate from

31. As frequency increases, the period ________. A) increases B) decreases C) doubles D) remains the same

32. If the available channel is a ____ channel, we cannot send a digital signal directly to the channel.

A) low-pass B) low rate C) bandpass D) high rate

33. For a ______ channel, the Nyquist bit rate formula defines the theoretical maximum bit rate. A) low-pass B) bandpass C) noisy D) noiseless

34. In a frequency-domain plot, the horizontal axis measures the ________. A) phase B) frequency C) slope D) peak amplitude

CHAPTER-4

DIGITAL TRANSMISSION

1. Which of the following encoding methods does not provide for synchronization? A) RZ B) NRZ-L C) NRZ-I D) Manchester

2. If the frequency spectrum of a signal has a bandwidth of 500 Hz with the highest frequency at 600 Hz, what should be the sampling rate, according to the Nyquist theorem?

A) 200 samples/s B) 500 samples/s C) 1000 samples/s D) 1200 samples/s

3. In asynchronous transmission, the gap time between bytes is _______. A) variable B) fixed C) zero D) a function of the data rate

4. ______ substitutes eight consecutive zeros with 000VB0VB. A) B4B8 B) B8ZS C) HDB3 D) none of the above

5. The most common technique to change an analog signal to digital data is called __________.

A) sampling B) PAL C) PCM D) none of the above

6. The minimum bandwidth of Manchester and differential Manchester is ____ that of NRZ. A) the same as B) twice C) thrice D) none of the above

7. The signal rate is sometimes called the ____ rate. A) bit B) baud C) signal D) none of the above

8. Unipolar, bipolar, and polar encoding are types of _______ encoding. A) line B) block C) NRZ D) Manchester

9. ________ is normally referred to as mB/nB coding; it replaces each m-bit group with an n-bit group.

A) Line coding B) Block coding

C) Scrambling D) None of the above

10. In ______ schemes, the voltages are on the both sides of the time axis. For example, the voltage level for 0 can be positive and the voltage level for 1 can be negative.

A) unipolar B) bipolar C) polar D) all of the above

11. The ________ rate defines the number of data elements sent in 1s; the ______ rate is the number of signal elements sent in 1s.

A) signal; data B) data; signal C) baud; bit D) none of the above

12. The idea of RZ and the idea of NRZ-L are combined into the ________ scheme. A) Manchester B) differential Manchester C) both (a) and (b) D) neither (a) nor (b)

13. ________ provides synchronization without increasing the number of bits. A) Line coding B) Block coding C) Scrambling D) None of the above

14. The Nyquist theorem specifies the minimum sampling rate to be_______. A) equal to the lowest frequency of a signal B) equal to the highest frequency of a signal C) twice the bandwidth of a signal D) twice the highest frequency of a signal

15. PCM is an example of _______ conversion. A) analog-to-analog B) analog-to-digital C) digital-to-digital D) digital-to-analog

16. There are three sampling methods: __________. A) ideal, natural, and flat-top B) ideal, sampled, and flat-top C) quantized, sampled, and ideal D) none of the above

17. In _______encoding, we use three levels: positive, zero, and negative. A) unipolar B) polar C) bipolar D) none of the above

18. Block coding can help in _______ at the receiver. A) Synchronization B) Error detection C) Attenuation D) (a) and (b)

19. In Manchester and differential Manchester encoding, the transition at the middle of the bit is used for __________.

A) bit transfer B) synchronization C) baud transfer D) none of the above

20. _______ encoding has a transition at the beginning of each 0 bit. A) Differential Manchester B) Manchester C) RZ D) All the above

21. In ______, the change or lack of change in the level of the voltage determines the value of the bit.

A) NRZ-L B) NRZ-I C) both (a) and (b) D) neither (a) nor (b)

22. In ___________ there is always a transition at the middle of the bit, but the bit values are determined at the beginning of the bit. If the next bit is 0, there is a transition; if the next bit is 1, there is none.

A) Manchester B) differential Manchester C) both (a) and (b) D) neither (a) nor (b)

23. In _______ encoding, the duration of the bit is divided into two halves. The voltage remains at one level during the first half and moves to the other level in the second half. The transition at the middle of the bit provides synchronization.

A) Manchester B) differential Manchester C) both (a) and (b) D) neither (a) nor (b)

24. The ________ mode provides synchronization for the entire stream of bits must. In other words, it guarantees that the data arrive at a fixed rate.

A) isochronous B) synchronous C) asynchronous D) none of the above

25. The idea of RZ and the idea of NRZ-I are combined into the ________ scheme. A) Manchester B) differential Manchester C) both (a) and (b) D) neither (a) nor (b)

26. In decoding a digital signal, the receiver calculates a running average of the received signal power, called the _______.

A) base B) line C) baseline D) none of the above

27. In _________ transmission, we send bits one after another without start or stop bits or gaps. It is the responsibility of the receiver to group the bits.

A) synchronous B) asynchronous C) isochronous D) none of the above

28. ______ finds the value of the signal amplitude for each sample; ____ finds the change from the previous sample.

A) DM; CM B) DM; PCM C) PCM; DM D) none of the above

29. ______ substitutes four consecutive zeros with 000V or B00V. A) HDB3 B) B4B8 C) B8ZSf D) none of the above

30. The ______ scheme uses three levels (+V, 0, and -V) and three transition rules to move between the levels.

A) 4B5B B) MLT-3 C) 2B1Q D) none of the above

31. While there is (are) only _____ way(s) to send parallel data, there is (are) _____ subclass(es) of serial transmission.

A) one; two B) one; three C) two; three D) none of the above

32. Which quantization level results in a more faithful reproduction of the signal? A) 2 B) 8 C) 16 D) 32

33. A _________ digital signal includes timing information in the data being transmitted. A) self-synchronizing B) self-transmitted C) self-modulated D) none of the above

34. In _______ transmission, bits are transmitted over a single wire, one at a time. A) asynchronous serial B) synchronous serial C) parallel D) (a) and (b)

35. The first step in PCM is ________. A) quantization B) sampling C) modulation D) none of the above

36. _______ encoding has a transition at the middle of each bit. A) Manchester B) Differential Manchester C) RZ D) All the above

37. In ______ transmission, we send 1 start bit (0) at the beginning and 1 or more stop bits (1s) at the end of each byte.

A) synchronous B) asynchronous C) isochronous D) none of the above

38. In _______ transmission, bits are transmitted simultaneously, each across its own wire. A) Asynchronous serial B) Synchronous serial C) Parallel D) (a) and (b)

39. Which encoding method uses alternating positive and negative values for 1s? A) AMI B) RZ C) NRZ-I D) Manchester

40. The data rate is sometimes called the ___ rate. A) bit B) baud C) signal D) none of the above

41. _______ provides redundancy to ensure synchronization and inherent error detection. A) Line coding B) Block coding C) Scrambling D) None of the above

42. In _______ transmission, a start bit and a stop bit frame a character byte. A) synchronous serial B) asynchronous serial C) parallel D) (a) and (b)

43. Two common scrambling techniques are ________. A) B8ZS and HDB3 B) AMI and NRZ C) NRZ and RZ D) Manchester and differential Manchester

44. ___________ conversion involves three techniques: line coding, block coding, and scrambling.

A) Analog-to-analog B) Analog-to-digital C) Digital-to-analog D) Digital-to-digital

45. The _____ scheme uses data patterns of size 2 and encodes the 2-bit patterns as one signal element belonging to a four-level signal.

A) MLT-3 B) 4B5B C) 2B1Q D) none of the above

46. In _____, the level of the voltage determines the value of the bit. A) NRZ-I B) NRZ-L C) both (a) and (b) D) neither (a) nor (b)

47. ________ is the process of converting digital data to a digital signal. A) Line coding B) Block coding C) Scrambling D) None of the above

48. In a _____ scheme, all the signal levels are on one side of the time axis, either above or below.

A) unipolar B) polar C) bipolar D) all of the above

CHAPTER-5

ANALOG TRANSMISSION

1. In ________, the amplitude of the carrier signal is varied to create signal elements. Both frequency and phase remain constant

A) PSK B) ASK C) FSK D) QAM

2. How many carrier frequencies are used in BPSK? A) 0 B) 1 C) 2 D) none of the above

3. The constellation diagram of 16-QAM has ______ dots. A) 4 B) 8 C) 16 D) none of the above

4. AM and FM are examples of ________ conversion. A) analog-to-analog B) digital-to-digital C) analog-to-digital D) digital-to-analog

5. The Federal Communications Commission (FCC) allows ______ kHz for each FM station. A) 20 B) 100 C) 200 D) none of the above

6. Analog-to-analog conversion is needed if the available bandwidth is _______. A) band-pass B) low-pass C) either (a) or (b) D) neither (a) nor (b)

7. In _____ transmission, the frequency of the carrier signal is modulated to follow the changing voltage level (amplitude) of the modulating signal. The peak amplitude and phase of the carrier signal remain constant, but as the amplitude of the information signal changes, the frequency of the carrier changes correspondingly.

A) AM B) FM C) PM D) none of the above

8. How many carrier frequencies are used in QPSK? A) 0 B) 2 C) 1 D) none of the above

9. Which of the following is not a digital-to-analog conversion? A) FSK B) ASK C) AM D) PSK

10. _______ conversion is the process of changing one of the characteristics of an analog signal based on the information in the digital data.

A) Analog-to-analog B) Digital-to-digital C) Digital-to-analog D) Analog-to-digital

11. If the baud rate is 400 for a QPSK signal, the bit rate is ________ bps. A) 100 B) 400 C) 800 D) 1600

12. In ________, the phase of the carrier is varied to represent two or more different signal elements. Both peak amplitude and frequency remain constant.

A) PSK B) FSK C) ASK D) QAM

13. Which of the following is not an analog-to-analog conversion? A) QAM B) AM C) PM D) FM

14. How many carrier frequencies are used in BASK? A) 0 B) 1 C) 2 D) none of the above

15. Quadrature amplitude modulation (QAM) is a combination of ___________. A) PSK and FSK B) ASK and FSK C) ASK and PSK D) none of the above

16. In _________, the frequency of the carrier signal is varied to represent data. Both peak amplitude and phase remain constant.

A) ASK B) FSK C) PSK D) QAM

17. If the bit rate for an ASK signal is 1200 bps, the baud rate is ________. A) 1200 B) 600 C) 400 D) 300

18. The constellation diagram of BPSK has ______ dots. A) 0 B) 1 C) 2 D) none of the above

19. The constellation diagram of QPSK has ______ dots. A) 4 B) 2 C) 1 D) none of the above

20. In _______, the peak amplitude of one signal level is 0; the other is the same as the amplitude of the carrier frequency.

A) OOK B) PSK C) FSK D) none of the above

21. If the bit rate for a 16-QAM signal is 4000 bps, what is the baud rate? A) 1200 B) 1000 C) 400 D) 300

22. ASK, PSK, FSK, and QAM are examples of ________ conversion. A) analog-to-analog B) digital-to-digital C) analog-to-digital D) digital-to-analog

23. If the bit rate for an FSK signal is 1200 bps, the baud rate is ________. A) 1200 B) 600

C) 400 D) 300

24. The constellation diagram of BASK has ______ dots. A) 0 B) 1 C) 2 D) none of the above

25. The Federal Communications Commission (FCC) allows ______kHz for each AM station. A) 20 B) 10 C) 5 D) none of the above

26. How many carrier frequencies are used in BFSK? A) 2 B) 1 C) 0 D) none of the above

27. In _____ transmission, the phase of the carrier signal is modulated to follow the changing voltage level (amplitude) of the modulating signal.

A) AM B) FM C) PM D) none of the above

28. _________ conversion is the representation of analog information by an analog signal. A) Analog-to-analog B) Digital-to-digital C) Analog-to-digital D) Digital-to-analog

29. In _____ transmission, the carrier signal is modulated so that its amplitude varies with the changing amplitudes of the modulating signal.

A) PM B) FM C) AM D) none of the above

30. In QAM, both ________ of a carrier frequency are varied. A) phase and frequency B) amplitude and phase C) frequency and amplitude D) none of the above

31. ________ uses two carriers, one in-phase and the other quadrature. A) QAM B) ASK C) FSK D) PSK

32. Given an AM radio signal with a bandwidth of 10 KHz and the highest-frequency component at 705 KHz, what is the frequency of the carrier signal?

A) 710 KHz B) 705 KHz C) 700 KHz D) Cannot be determined from given information

33. A constellation diagram shows us the __________ of a signal element, particularly when we are using two carriers (one in-phase and one quadrature).

A) amplitude and frequency B) amplitude and phase C) frequency and phase D) none of the above

34. If the baud rate for a 64-QAM signal is 2000, what is the bit rate? A) 12000 B) 1000 C) 400 D) 300

CHAPTER-6

BANDWIDTH UTILIZATION: MULTIPLEXING AND SPREADING

1. The _______ technique uses M different carrier frequencies that are modulated by the source signal. At one moment, the sign modulates one carrier frequency; at the next moment, the signal modulates another carrier frequency.

A) DSSS B) FHSS C) FDM D) TDM

2. In synchronous TDM, for n signal sources of the same data rate, each frame contains _______ slots.

A) n + 1 B) n - 1 C) 0 to n D) n

3. Which multiplexing technique transmits digital signals? A) WDM B) FDM C) TDM D) None of the above

4. The sharing of a medium and its link by two or more devices is called _______. A) modulation B) multiplexing C) encoding D) line discipline

5. _______ is designed to be used in wireless applications in which stations must be able to share the medium without interception by an eavesdropper and without being subject to jamming from a malicious intruder.

A) Multiplexing B) Spread spectrum C) Modulation D) None of the above.

6. ______ is an analog multiplexing technique to combine optical signals. A) WDM B) FDM C) TDM

D) None of the above 7. FDM is an _________technique.

A) digital B) analog C) either (a) or (b) D) none of the above

8. ______ can be applied when the bandwidth of a link (in hertz) is greater than the combined bandwidths of the signals to be transmitted.

A) TDM B) FDM C) Both (a) or (b) D) Neither (a) or (b)

9. In TDM, the transmission rate of the multiplexed path is usually _______ the sum of the transmission rates of the signal sources.

A) equal to B) less than C) greater than D) not related to

10. In a multiplexed system, __ lines share the bandwidth of ____ link. A) 1; n B) n; 1 C) 1; 1 D) n; n

11. _________ utilization is the use of available bandwidth to achieve specific goals. A) Amplitude B) Frequency C) Bandwidth D) None of the above

12. ____ is designed to use the high bandwidth capability of fiber-optic cable. A) WDM B) FDM C) TDM D) None of the above

13. We can divide ____ into two different schemes: synchronous or statistical. A) WDM B) TDM C) FDM D) none of the above

14. In ________ TDM, each input connection has an allotment in the output even if it is not sending data.

A) isochronous B) statistical C) synchronous D) none of the above

15. In ________ TDM, slots are dynamically allocated to improve bandwidth efficiency. A) isochronous B) synchronous C) statistical D) none of the above

16. The word ______ refers to the portion of a _______ that carries a transmission. A) line; channel B) channel; link C) link; channel D) line; link

17. Which multiplexing technique shifts each signal to a different carrier frequency? A) FDM B) TDM C) Both (a) and (b) D) None of the above

18. Which multiplexing technique transmits analog signals? A) WDM B) TDM C) FDM D) (a) and (c)

19. ________ is the set of techniques that allows the simultaneous transmission of multiple signals across a single data link.

A) Demodulating B) Multiplexing C) Compressing D) None of the above

20. ________ can be achieved by using multiplexing; ______ can be achieved by using spreading.

A) Privacy and antijamming; efficiency B) Privacy and efficiency; antijamming C) Efficiency; privacy and antijamming D) Efficiency and antijamming; privacy

21. The ______ technique expands the bandwidth of a signal by replacing each data bit with n bits.

A) DSSS B) FHSS C) FDM D) TDM

22. ________ is a digital process that allows several connections to share the high bandwidth of a link.

A) WDM B) TDM C) FDM D) None of the above

23. _______ is a digital multiplexing technique for combining several low-rate channels into one high-rate one.

A) WDM B) TDM C) FDM D) None of the above

24. In ________, we combine signals from different sources to fit into a larger bandwidth. A) line coding B) block coding C) spread spectrum D) none of the above

25. Which multiplexing technique involves signals composed of light beams? A) WDM B) FDM C) TDM D) none of the above

CHAPTER-7

TRANSMISSION MEDIA

1. When the angle of incidence is _______ the critical angle, the light beam bends along the interface.

A) less than B) equal to C) more than D) none of the above

2. Transmission media lie below the _______ layer. A) application B) transport C) network D) physical

3. _________ cable consists of an inner copper core and a second conducting outer sheath. A) Twisted-pair B) Shielded twisted-pair C) Coaxial D) Fiber-optic

4. __________ consists of a central conductor and a shield. A) Twisted-pair B) Coaxial C) Fiber-optic D) none of the above

5. _______ cable can carry signals of higher frequency ranges than _______ cable. A) Coaxial; twisted-pair B) Twisted-pair; fiber-optic C) Coaxial; fiber-optic D) none of the above

6. _________ are used for cellular phone, satellite, and wireless LAN communications. A) Radio waves B) Infrared waves C) Microwaves D) none of the above

7. The inner core of an optical fiber is _______ in composition. A) copper B) glass or plastic C) bimetallic D) liquid

8. What is the major factor that makes coaxial cable less susceptible to noise than twisted-pair cable?

A) insulating material B) inner conductor C) diameter of cable D) outer conductor

9. Signals with a frequency below 2 MHz use _______ propagation. A) line-of-sight B) sky C) ground D) none of the above

10. In an optical fiber, the inner core is _______ the cladding. A) less dense than B) denser than C) the same density as D) another name for

11. ________ cable consists of two insulated copper wires twisted together. A) Twisted-pair B) Coaxial C) Fiber-optic D) none of the above

12. In fiber optics, the signal is _______ waves. A) radio B) light C) infrared D) very low-frequency

13. Signals with a frequency above 30 MHz use _______propagation. A) line-of-sight B) sky C) ground D) none of the above

14. A parabolic dish antenna is a(n) _______ antenna. A) unidirectional B) bidirectional C) omnidirectional D) horn

15. A(n) _______ medium provides a physical conduit from one device to another. A) unguided B) guided C) either (a) or (b) D) none of the above

16. ________ cable is used for voice and data communications. A) Twisted-pair B) Coaxial C) Fiber-optic D) none of the above

17. Signals with a frequency between 2 MHz and 30 MHz use _______ propagation. A) ground B) line-of-sight C) sky

D) none of the above 18. Transmission media are usually categorized as _______.

A) determinate or indeterminate B) fixed or unfixed C) guided or unguided D) metallic or nonmetallic

19. ________ are used for short-range communications such as those between a PC and a peripheral device.

A) Radio waves B) Infrared waves C) Microwaves D) none of the above

20. _________ media transport electromagnetic waves without the use of a physical conductor. A) Guided B) Unguided C) Either (a) or (b) D) None of the above

21. ________ cables are composed of a glass or plastic inner core surrounded by cladding, all encased in an outside jacket.

A) Twisted-pair B) Coaxial C) Fiber-optic D) none of the above

22. Which of the following primarily uses guided media? A) radio broadcasting B) satellite communications C) local telephone system D) cellular telephone system

23. When a beam of light travels through media of two different densities, if the angle of incidence is greater than the critical angle, _______ occurs.

A) refraction B) reflection C) criticism D) incidence

24. Which of the following is not a guided medium? A) fiber-optic cable B) coaxial cable C) twisted-pair cable D) atmosphere

25. Microwaves are _________. A) omnidirectional B) bidirectional C) unidirectional D) none of the above

26. ________ cables carry data signals in the form of light. A) Twisted-pair B) Coaxial C) Fiber-optic D) none of the above

27. Radio waves are _________. A) unidirectional B) omnidirectional C) bidirectional D) none of the above

28. In a fiber-optic cable, the signal is propagated along the inner core by _______. A) refraction B) reflection C) modulation D) none of the above

CHAPTER-8

SWITCHING

1. Packet-switched networks can also be divided into ______subcategories: virtual-circuit networks and datagram networks.

A) five B) three C) two D) four

2. In __________, each packet is treated independently of all others. A) circuit switching B) datagram switching C) frame switching D) none of the above

3. Based on the Clos criteria, if N = 200, then k must be equal to or greater than ______. A) 19 B) 21 C) 31 D) 41

4. In _________, resources are allocated on demand. A) circuit switching B) datagram switching C) frame switching D) none of the above

5. In _______ switching, the paths in the circuit are separated from one another spatially. A) time-division B) two-dimensional C) space-division D) three-dimensional

6. In a ________ network, two types of addressing are involved: global and local. A) datagram B) virtual-circuit C) circuit-switched D) none of the above

7. In a three-stage space division switch, if N = 200, the number of crosspoints is ______. A) 40,000 B) less than 40,000

C) greater than 40,000 D) greater than 100,000

8. A ________ network is made of a set of switches connected by physical links, in which each link is divided into n channels.

A) circuit-switched B) line-switched C) frame-switched D) none of the above

9. In a banyan switch, for 8 inputs and 8 outputs, we have _____ microswitches at each stage. A) 2 B) 3 C) 4 D) 8

10. In _________, there is no resource allocation for a packet. A) circuit switching B) datagram switching C) frame switching D) none of the above

11. A _________ network is a cross between a circuit-switched network and a datagram network. It has some characteristics of both.

A) packet-switched B) frame-switched C) virtual-circuit D) none of the above

12. The most popular technology in time-division switching is called the _________. A) TSI B) STI C) ITS D) none of the above

13. A switched WAN is normally implemented as a _______ network. A) virtual-circuit B) datagram C) circuit-switched D) none of the above

14. We can say that a packet switch has _______ types of components. A) four B) three C) two D) none of the above

15. In a one-stage space division switch, if N = 200, the number of crosspoints is ______. A) 20,000 B) 40,000 C) 30,000 D) 10,000

16. In a banyan switch, for 8 inputs and 8 outputs, we have _____ stages. A) 2 B) 3 C) 4 D) 8

17. A switch in a datagram network uses a routing table that is based on the ______ address. A) destination B) source C) local D) none of the above

18. Traditionally, _____ methods of switching have been important. A) six B) five C) four D) three

19. The network layer in the Internet is designed as a __________ network. A) circuit-switched B) datagram C) virtual-circuit D) none of the above

20. A ________ switch combines space-division and time-division technologies to take advantage of the best of both.

A) SSS B) TST C) TTT D) none of the above

21. In _______, the resources need to be reserved during the setup phase; the resources remain dedicated for the entire duration of data transfer phase until the teardown phase.

A) frame switching B) datagram switching C) circuit switching D) none of the above

22. Based on the Clos criteria, if N = 200, then n must be equal to or greater than ____. A) 40 B) 30 C) 20 D) 10

23. Circuit switching takes place at the ________ layer. A) physical B) data line C) network D) transport

24. A ________ switch combines crossbar switches in several (normally three) stages. A) multiple path B) multiple crossbar C) multistage D) none of the above

25. In _______ there are no setup or teardown phases. A) circuit switching B) datagram switching C) frame switching D) none of the above

26. We can divide today's networks into ____ broad categories. A) five B) four

C) three D) two

27. A ________ switch is a multistage switch with microswitches at each stage that route the packets based on the output port represented as a binary string.

A) TSI B) banyan C) crossbar D) none of the above

28. The _______ address in the header of a packet in a datagram network normally remains the same during the entire journey of the packet.

A) destination B) source C) local D) none of the above

29. Based on the Clos criteria, if N = 200, then the minimum number of crosspoints is greater than or equal to _______.

A) 42,000 B) 20,000 C) 18,000 D) 15,200

30. The simplest type of switching fabric is the ______ switch. A) crossbar B) crosspoint C) TSI D) STS

CHAPTER-9

USING TELEPHONE AND CABLE NETWORKS FOR DATA TRANSMISSION

1. To use a cable network for data transmission, we need two key devices: a ______ and a _________

A) CT; CMTS B) CM; CMTS C) CM; CMS D) none of the above

2. A local telephone network is an example of a _______ network. A) packet-switched B) message-switched C) circuit-switched D) none of the above

3. A traditional cable TV network transmits signals ______. A) downstream B) upstream C) upstream and downstream D) none of the above

4. The traditional cable TV system used ________cable end to end. A) twisted-pair B) fiber-optic C) coaxial D) none of the above

5. The telephone network is made of ______ major components. A) 4 B) 3 C) 2 D) none of the above

6. Data from a computer are _______; the local loop handles _______ signals. A) analog; analog B) digital; digital C) digital; analog D) analog; digital

7. The original telephone network, which is referred to as the plain old telephone system (POTS), was an ________ system.

A) analog B) digital C) digital as well as analog D) none of the above

8. The protocol that is used for signaling in the telephone network is called ______. A) SSS B) SS7 C) POP D) none of the above

9. _______technology is a set of technologies developed by the telephone companies to provide high data rate transmission.

A) LDS B) ASL C) DSL D) none of the above

10. The local loop has _______ cable that connects the subscriber telephone to the nearest end office.

A) fiber-optic B) coaxial C) twisted-pair D) none of the above

11. The second generation of cable networks is called a(n) _________ network. A) HCF B) HFC C) CFH D) none of the above

12. The largest portion of the bandwidth for ADSL carries _______. A) upstream data B) downstream data C) control data D) voice communication

13. _______ is suitable for businesses that require comparable upstream and downstream data rates.

A) SDSL B) ADSL C) VDSL D) (b) and (c)

14. The carrier that handles intra-LATA services is called a(n) _____ . A) IXC B) LEC C) POP D) none of the above

15. DMT is a modulation technique that combines elements of _______ and _______. A) FDM; QAM B) FDM; TDM C) PSK; FSK D) QDM; QAM

16. The carrier that handles inter-LATA services is called a(n) _______. A) IXC B) LEC C) POP D) none of the above

17. The modern telephone network is now ________. A) digital B) digital as well as analog C) analog D) none of the above

18. In an HFC network, the upstream data are modulated using the _______ modulation technique.

A) ASK B) PCM C) QAM D) QPSK

19. _______ was designed as an alternative to the T-1 line. A) ADSL B) HDSL C) VDSL D) SDSL

20. HDSL encodes data using _______. A) 2B1Q B) 1B2Q C) 4B/5B D) 6B/8T

21. In an HFC network, the downstream data are modulated using the _______ modulation technique.

A) PCM B) QAM C) PSK D) ASK

22. Another name for the cable TV office is the _______. A) head end B) combiner C) fiber node D) splitter

23. The term modem is a composite word that refers to the two functional entities that make up the device: a signal _______ and a signal _______.

A) demodulator; modulator B) modulator; demodulator C) modern; demo D) none of the above

24. The two most common digital services are ________ service and ______. A) switched/56; DDS B) switched/56; switched/64 C) DDS; swiched 64 D) leased; out-of-band

25. The United States is divided into many _______. A) IXCs B) LECs C) LATAs D) none of the above

26. The standard for data transmission over an HFC network is called _______. A) ADSL B) CMTS C) DOCSIS D) MCNS

27. In ________signaling, a portion of the bandwidth is used for signaling and another portion for data.

A) mixed B) in-band C) out-of-band D) none of the above

28. Telephone companies provide two types of analog services: analog _______ services and analog _____services.

A) leased; out-of-band B) out-of-band; in-band C) switched; in-band D) switched; leased

29. The HFC network uses _______ cable. A) coaxial B) twisted-pair C) fiber-optic D) a combination of (a) and (c)

30. In ______signaling, the same circuit is used for both signaling and data. A) mixed B) out-of-band C) in-band D) none of the above

31. Most popular modems available are based on the ________standards. A) X-series B) V-series C) VX-series D) none of the above

CHAPTER-10

ERROR DETECTION AND CORRECTION

1. Checksums use _________ arithmetic. A) one's complement arithmetic B) two's complement arithmetic C) either (a) or (b) D) none of the above

2. The checksum of 1111 and 1111 is _________. A) 0000 B) 1111 C) 1110 D) 0111

3. In modulo-11 arithmetic, we use only the integers in the range ______, inclusive. A) 1 to 10 B) 0 to 10 C) 1 to 11 D) none of the above

4. In cyclic redundancy checking, the divisor is _______ the CRC. A) one bit less than B) one bit more than C) The same size as D) none of the above

5. The ________ between two words is the number of differences between corresponding bits. A) Hamming rule B) Hamming code C) Hamming distance D) none of the above

6. The _______ of a polynomial is the highest power in the polynomial. A) range B) power C) degree D) none of the above

7. In modulo-2 arithmetic, __________ give the same results. A) addition and subtraction B) addition and multiplication C) addition and division D) none of the above

8. In cyclic redundancy checking, what is the CRC? A) The quotient B) The dividend C) The divisor D) The remainder

9. Which error detection method consists of just one redundant bit per data unit? A) CRC B) Checksum C) Simple parity check D) Two-dimensional parity check

10. In _____ coding, we divide our message into blocks, each of k bits, called ___. A) block; blockwords B) block; datawords C) linear; datawords D) none of the above

11. A _____ error means that two or more bits in the data unit have changed. A) burst B) double-bit C) single-bit D) none of the above

12. Adding 1 and 1 in modulo-2 arithmetic results in _________. A) 0 B) 1 C) 2 D) none of the above

13. In ________ error correction, the receiver corrects errors without requesting retransmission. A) onward B) forward C) backward D) none of the above

14. If the Hamming distance between a dataword and the corresponding codeword is three, there are _____ bits in error.

A) 5 B) 4 C) 3 D) none of the above

15. A simple parity-check code can detect __________ errors. A) an odd-number of B) an even-number of C) two D) no errors

16. The Hamming distance between equal codewords is _________. A) 0 B) 1 C) n D) none of the above

17. In a linear block code, the _______ of any two valid codewords creates another valid codeword.

A) ANDing B) XORing C) ORing D) none of the above

18. In ________ error correction, the receiver asks the sender to send the data again. A) forward B) backward

C) retransmission D) none of the above

19. We can divide coding schemes into two broad categories: ________ and ______coding. A) linear; nonlinear B) block; convolution C) block; linear D) none of the above

20. In modulo-2 arithmetic, we use only ______. A) 1 and 2 B) 0 and 1 C) 0 and 2 D) none of the above

21. To guarantee correction of up to 5 errors in all cases, the minimum Hamming distance in a block code must be ________.


22. The _____of errors is more difficult than the ______. A) detection; correction B) correction; detection C) creation; correction D) creation; detection

23. In block coding, if k =2 and n =3, we have _______ invalid codewords. A) 4 B) 8 C) 2 D) none of the above

24. The checksum of 0000 and 0000 is __________. A) 0000 B) 1111 C) 0111 D) 1110

25. In one's complement arithmetic, if positive 7 is 0111, then negative 7 is ________. A) 1101 B) 1000 C) 1111 D) none of the above

26. In block coding, if n = 5, the maximum Hamming distance between two codewords is ________.


27. Which error detection method uses one's complement arithmetic? A) Checksum B) CRC C) Simple parity check D) Two-dimensional parity check

28. The divisor in a cyclic code is normally called the _________. A) redundancy B) degree C) generator D) none of the above

29. In modulo-2 arithmetic, we use the ______ operation for both addition and subtraction. A) OR B) XOR C) AND D) none of the above

30. We add r redundant bits to each block to make the length n = k + r. The resulting n-bit blocks are called _________.

A) codewords B) datawords C) blockwords D) none of the above

31. To guarantee the detection of up to 5 errors in all cases, the minimum Hamming distance in a block code must be _______.


32. A generator that contains a factor of ____ can detect all odd-numbered errors. A) x B) 1 C) x + 1 D) none of the above

33. _______codes are special linear block codes with one extra property. If a codeword is rotated, the result is another codeword.

A) Convolution B) Cyclic C) Non-linear D) none of the above

34. The Hamming distance between 100 and 001 is ________. A) 0 B) 1 C) 2 D) none of the above

CHAPTER-11

DATALINK CONTROL

1. In Go-Back-N ARQ, if 5 is the number of bits for the sequence number, then the maximum size of the receive window must be _____.

A) 1 B) 15 C) 16 D) 31

2. In Go-Back-N ARQ, if frames 4, 5, and 6 are received successfully, the receiver may send an ACK _______ to the sender.

A) 6 B) 7 C) 5 D) any of the above

3. The Stop-And-Wait ARQ, Go-Back-N ARQ, and the Selective Repeat ARQ are for ______ channels.

A) noiseless B) noisy C) either (a) or (b) D) neither (a) nor (b)

4. The _________Protocol, adds a simple error control mechanism to the _______Protocol. A) Selective Repeat ARQ; Go-Back-N ARQ B) Go-Back-N ARQ; Stop-and-Wait C) Stop-and-Wait ARQ; Stop-and-Wait D) none of the above

5. In PPP, the ________ is responsible for establishing, maintaining, configuring, and terminating links.

A) PAP B) CHAP C) LCP D) NCP

6. HDLC is an acronym for _______. A) Half-duplex digital link combination B) Host double-level circuit C) High-duplex line communication D) High-level data link control

7. In Selective Repeat ARQ, if 5 is the number of bits for the sequence number, then the maximum size of the receive window must be _____.

A) 1 B) 15 C) 16 D) 31

8. In Go-Back-N ARQ, if 5 is the number of bits for the sequence number, then the maximum size of the send window must be _____.

A) 1 B) 15 C) 16 D) 31

9. In Stop-and-Wait ARQ, the acknowledgment number always announces in ______ arithmetic the sequence number of the next frame expected.

A) modulo-m B) modulo-2 C) modulo-4 D) none of the above

10. In Selective Repeat ARQ, if 5 is the number of bits for the sequence number, then the maximum size of the send window must be _____.

A) 1 B) 15

C) 16 D) 31

11. _______ control refers to a set of procedures used to restrict the amount of data that the sender can send before waiting for acknowledgment.

A) Flow B) Error C) Transmission D) none of the above

12. In the Go-Back-N Protocol, if the size of the sequence number field is 8, the sequence numbers are in ________ arithmetic,

A) modulo-256 B) modulo- 8 C) modulo-2 D) none of the above

13. ______ control refers to methods of error detection and correction. A) Flow B) Error C) Transmission D) none of the above

14. In a Go-Back-N ARQ, if the window size is 63, what is the range of sequence numbers? A) 1 to 63 B) 1 to 64 C) 0 to 63 D) 0 to 64

15. Both Go-Back-N and Selective-Repeat Protocols use a _________. A) sliding window B) sliding frame C) sliding packet D) none of the above

16. In _________, the configuration is balanced. The link is point-to-point, and each station can function as a primary and a secondary.

A) ARM B) ABM C) NBM D) NRM

17. Byte stuffing means adding a special byte to the data section of the frame when there is a character with the same pattern as the ______.

A) trailer B) flag C) header D) none of the above

18. The ______ Protocol has neither flow nor error control. A) Selective-Repeat ARQ B) Go-Back-N ARQ C) Stop-and-Wait D) Simplest

19. The most common protocol for point-to-point access is the Point-to-Point Protocol (PPP), which is a _________protocol.

A) byte-oriented B) bit-oriented

C) character-oriented D) none of the above

20. For Stop-and-Wait ARQ, for 10 data packets sent, _______ acknowledgments are needed. A) less than 10 B) more than 10 C) exactly 10 D) none of the above

21. _________framing uses two categories of protocols: character-oriented and bit-oriented. A) Standard B) Fixed-size C) Variable-size D) None of the above

22. _______ control refers to a set of procedures used to restrict the amount of data that the sender can send before waiting for acknowledgment.


23. In a ________ protocol, the data section of a frame is a sequence of characters. A) bit-oriented B) character-oriented C) either (a) or (b) D) none of the above

24. In _______ framing, there is no need for defining the boundaries of frames. A) standard B) fixed-size C) variable-size D) none of the above

25. The _______Protocol has both flow control and error control. A) Stop-and-Wait B) Selective-Repeat ARQ C) Go-Back-N ARQ D) both (b) and (c)

26. In _________, the station configuration is unbalanced. We have one primary station and multiple secondary stations.

A) ARM B) NBM C) NRM D) ABM

27. In a _________ protocol, the data section of a frame is a sequence of bits. A) bit-oriented B) byte-oriented C) either (a) or (b) D) none of the above

28. In ________ framing, we need a delimiter (flag) to define the boundary of two frames. A) standard B) fixed-size C) variable-size D) none of the above

29. High-level Data Link Control (HDLC) is a _______ protocol for communication over point-to-point and multipoint links.

A) byte-oriented B) bit-oriented C) character-oriented D) none of the above

30. Bit stuffing means adding an extra 0 to the data section of the frame when there is a sequence of bits with the same pattern as the ________.

A) trailer B) flag C) header D) none of the above

31. In the _________Protocol, if no acknowledgment for a frame has arrived, we resend all outstanding frames.

A) Go-Back-N ARQ B) Selective-Repeat ARQ C) Stop-and-Wait ARQ D) none of the above

32. The Simplest Protocol and the Stop-and-Wait Protocol are for ______ channels. A) noiseless B) noisy C) either (a) or (b) D) neither (a) nor (b)

33. The _______Protocol has flow control, but not error control. A) Selective-Repeat ARQ B) Stop-and-Wait C) Simplest D) Go-Back-N ARQ

34. In Stop-and-Wait ARQ, we use sequence numbers to number the frames. The sequence numbers are based on __________arithmetic.

A) modulo-m B) modulo-2 C) modulo-4 D) none of the above

35. In the _____ Protocol, the sender sends its frames one after another with no regard to the receiver.

A) Simplest B) Selective-Repeat ARQ C) Stop-and-Wait D) Go-Back-N ARQ

36. _________control in the data link layer is based on automatic repeat request, which is the retransmission of data.


37. In PPP, _______ is a three-way hand-shaking authentication protocol in which the password is kept secret; it is never sent online.

A) PAP B) LCP

C) NCP D) CHAP

38. In PPP, ________ is a simple authentication procedure with a two-step process: A) CHAP B) PAP C) LCP D) NCP

39. In the _________ protocol we avoid unnecessary transmission by sending only frames that are corrupted.

A) Selective-Repeat ARQ B) Stop-and-Wait ARQ C) Go-Back-N ARQ D) none of the above

40. In ________ protocols, we use ________. A) byte-oriented; bit stuffing B) bit-oriented; bit stuffing C) character-oriented; bit stuffing D) none of the above

41. In the _____ Protocol, the sender sends one frame, stops until it receives confirmation from the receiver, and then sends the next frame.

A) Simplest B) Stop-and-Wait C) Selective-Repeat ARQ D) Go-Back-N ARQ

42. Stop-and-Wait ARQ is a special case of Go-Back-N ARQ in which the size of the send window is ___.


43. ARQ stands for _______. A) Acknowledge repeat request B) Automatic retransmission request C) Automatic repeat quantization D) Automatic repeat request

44. _______ in the data link layer separates a message from one source to a destination, or from other messages going from other sources to other destinations.

A) Controlling B) Framing C) Digitizing D) none of the above

45. Data link control deals with the design and procedures for ______ communication. A) node-to-node B) process-to-process C) host-to-host D) none of the above

46. In _________ protocols, we use ________. A) bit-oriented; character stuffing B) character-oriented; bit stuffing C) character-oriented; byte stuffing D) none of the above

CHAPTER-12

MULTIPLE ACCESSES

1. In _______, the stations share the bandwidth of the channel in time. A) FDMA B) CDMA C) TDMA D) none of the above

2. In ______, the chance of collision can be reduced if a station senses the medium before trying to use it.

A) CSMA B) MA C) CDMA D) FDMA

3. In the _______ method, the stations in a network are organized in a logical ring. A) polling B) token passing C) reservation D) none of the above

4. In _______, the sequences are generated using orthogonal codes such the Walsh tables. A) TDMA B) CDMA C) FDMA D) none of the above

5. __________ augments the CSMA algorithm to detect collision. A) CSMA/CD B) CSMA/CA C) either (a) or (b) D) both (a) and (b)

6. In the _________ method, after the station finds the line idle, it sends its frame immediately. If the line is not idle, it continuously senses the line until it finds it idle.

A) p-persistent B) nonpersistent C) 1-persistent D) none of the above

7. In the _____ method, time is divided into intervals. In each interval, a reservation frame precedes the data frames sent in that interval.

A) token passing B) reservation C) polling D) none of the above

8. In the _______ method, each station has a predecessor and a successor. A) token passing B) polling C) reservation D) none of the above

9. The vulnerable time for CSMA is the ________propagation time. A) three times B) two times C) the same as D) none of the above

10. In the _________ method, a special packet called a ______ circulates through the ring. A) polling: poll request B) token passing: token C) reservation: control frame D) none of the above

11. The maximum throughput for pure ALOHA is ________ per cent. A) 36.8 B) 18.4 C) 12.2 D) none of the above

12. In ________, the available bandwidth is divided into frequency bands. A) TDMA B) CDMA C) FDMA D) none of the above

13. In ___________ methods, no station is superior to another station and none is assigned the control over another.

A) controlled access B) random access C) channelization D) none of the above

14. In the ________method, a station that has a frame to send senses the line. If the line is idle, it sends immediately. If the line is not idle, it waits a random amount of time and then senses the line again.

A) 1-persistent B) nonpersistent C) p-persistent D) none of the above

15. In ______, each station is allocated a band to send its data. In other words, each band is reserved for a specific station, and it belongs to the station all the time.

A) CDMA B) FDMA C) TDMA D) none of the above

16. In the _______method, after the station finds the line idle it sends or refrain from sending based on the outcome of a random number generator. If the line is busy, it tries again.

A) p-persistent B) nonpersistent C) 1-persistent D) none of the above

17. To avoid collisions on wireless networks, ________was invented. A) CSMA/CD B) CSMA/CA C) either (a) or (b) D) both (a) and (b)

18. In _____, each station is allocated a time slot during which it can send data. Each station transmits its data in its assigned time slot.

A) TDMA B) CDMA C) FDMA D) none of the above

19. In the _______ method, the primary device controls the link; the secondary devices follow its instructions.

A) token passing B) reservation C) polling D) none of the above

20. In _____, each station transmits its data in its assigned time slot. A) TDMA B) CDMA C) FDMA D) none of the above

21. We discussed ________ channelization protocols. A) four B) three C) two D) none of the above

22. In the ______ method, all data exchanges must be made through the primary device even when the ultimate destination is a secondary device.

A) polling B) token passing C) reservation D) none of the above

23. We discussed ______ popular controlled-access methods. A) four B) three C) two D) none of the above

24. In __________, each station is forced to send only at the beginning of the time slot. A) pure ALOHA B) slotted ALOHA C) both (a) and (b) D) neither (a) nor (b)

25. In _______ methods, the stations consult one another to find which station has the right to send.

A) channelization B) random access C) controlled access D) none of the above

26. In ________ each station sends a frame whenever it has a frame to send. A) slotted ALOHA B) pure ALOHA C) both (a) and (b) D) neither (a) nor (b)

27. In ______, the stations use different codes to achieve multiple access. A) CDMA B) TDMA C) FDMA D) none of the above

28. In _______, collisions are avoided through the use of three strategies: the interframe space, the contention window, and acknowledgments.

A) CSMA/CD B) CSMA/CA C) either (a) or (b) D) both (a) and (b)

29. In the ________ method, a station needs to make a reservation before sending data. Time is divided into intervals.

A) token passing B) polling C) reservation D) none of the above

30. In pure ALOHA, the vulnerable time is ______ the frame transmission time. A) two times B) three times C) the same as D) none of the above

31. The maximum throughput for slotted ALOHA is ________ per cent. A) 36.8 B) 18.4 C) 12.2 D) none of the above

32. _________ is a multiple-access method in which the available bandwidth of a link is shared in time, frequency, or through code, between different stations.

A) Controlled access B) Channelization C) Random access D) none of the above

33. ________ requires that each station first listen to the medium before sending. A) FDMA B) CDMA C) MA D) CSMA

34. We have categorized access methods into _______ groups. A) five B) three C) four D) two

35. In _______ methods, a station cannot send unless it has been authorized by other stations. A) controlled access B) channelization C) random access D) none of the above

36. In slotted ALOHA, the vulnerable time is ______ the frame transmission time. A) two times B) three times C) the same as D) none of the above

37. In ________, a station monitors the medium after it sends a frame to see if the transmission was successful. If so, the station is finished. If, however, there is a collision, the frame is sent again.

A) CSMA/CD B) CSMA/CA C) either (a) or (b) D) both (a) and (b)

38. _______ is based on coding theory and uses sequences of numbers called chips. A) TDMA B) CDMA C) FDMA D) none of the above

CHAPTER-13

WIRED LANS: ETHERNET

1. __________ uses four twisted pairs. A) 1000Base-LX B) 1000Base-T C) 1000Base-SX D) none of the above

2. 1000Base-SX, 1000Base-LX, and 1000Base-CX use _________ block coding and ________ line coding.

A) 8B/10B; NRZ B) 4B/5B; NRZ C) 8B/10B; NRZ D) 4B/5B; MLT-3

3. _________ uses two fiber-optic cables. A) 100Base-FX B) 100Base-T4 C) 100Base-TX D) none of the above

4. __________ uses two optical fibers and a short-wave laser source. A) 1000Base-LX B) 1000Base-SX C) 1000Base-T D) none of the above

5. What is the hexadecimal equivalent of the Ethernet address 01011010 00010001 01010101 00011000 10101010 00001111?

A) 5A:81:BA:81:AA:0F B) 5A:11:55:18:AA:0F C) 5A:88:AA:18:55:F0 D) 5A:18:5A:18:55:0F

6. In Ethernet addressing, if all the bits are 1s, the address is _________. A) multicast B) broadcast C) unicast D) none of the above

7. If an Ethernet destination address is 07:01:02:03:04:05, then this is a ______ address. A) broadcast B) unicast C) multicast D) any of the above

8. Each station on an Ethernet network has a unique _______ address imprinted on its network interface card (NIC).

A) 48-bit B) 32-bit C) 5-byte D) none of the above

9. Gigabit Ethernet has a data rate of ________Mbps. A) 10,000 B) 1000 C) 100 D) 10

10. In the Ethernet frame, the _______ field contains error detection information. A) address B) preamble C) CRC D) none of the above

11. 100Base-T4 uses ________ line coding. A) 8B6T B) Manchester C) MLT-3 D) NRZ

12. ________uses long-wave 1310-nm single mode fiber. A) 10GBase-E B) 10GBase-S C) 10GBase-L D) none of the above

13. ______defines a protocol data unit (PDU) that is somewhat similar to that of HDLC. A) LLC B) LLU C) MAC D) none of the above

14. 100Base-TX uses _________ block coding and ________ line coding. A) 8B/10B; NRZ B) 4B/5B; MLT-3 C) 4B/5B; NRZ D) 8B/10B; NRZ

15. The _____ sublayer is responsible for the operation of the CSMA/CD access method and framing.

A) MAC B) MII

C) LLC D) none of the above

16. _______ is the most widely used local area network protocol. A) Token Bus B) Ethernet C) Token Ring D) none of the above

17. In Ethernet addressing, if the least significant bit of the first byte is 1, the address is _________.

A) multicast B) broadcast C) unicast D) none of the above

18. Gigabit Ethernet access methods include _______ mode. A) full-duplex B) half-duplex C) both (a) and (b) D) neither (a) nor (b)

19. _________ uses four pairs of voice-grade, or higher, twisted-pair cable. A) 100Base-T4 B) 100Base-FX C) 100Base-TX D) none of the above

20. Standard Ethernet (10-Mbps) uses _______ encoding. A) AMI B) Manchester C) NRZ D) differential Manchester

21. In _________, auto negotiation allows two devices to negotiate the mode or data rate of operation.

A) Ten-Gigabit Ethernet B) Gigabit Ethernet C) Fast Ethernet D) Standard

22. If an Ethernet destination address is 08:07:06:05:44:33, then this is a ______ address. A) broadcast B) unicast C) multicast D) any of the above

23. ________ uses short-wave 850-nm multimode fiber. A) 10GBase-E B) 10GBase-L C) 10GBase-S D) none of the above

24. Which of the following could not be an Ethernet multicast destination? A) 7B:AA:C1:23:45:32 B) 7C:56:21:1A:DE:F4 C) 83:32:21:21:4D:34 D) B7:7B:6C:DE:10:00

25. __________ uses thin coaxial cable. A) 10Base2 B) 10Base5 C) 10Base-F D) 10Base-T

26. In the Ethernet, the _______field is actually added at the physical layer and is not (formally) part of the frame.

A) address B) CRC C) preamble D) none of the above

27. Fast Ethernet has a data rate of ________Mbps. A) 10,000 B) 1000 C) 100 D) 10

28. The purpose of the _______ is to provide flow and error control for the upper-layer protocols that actually demand these services.

A) LLC B) LLU C) MAC D) none of the above

29. __________ uses two pairs of twisted-pair cable. A) 100Base-T4 B) 100Base-TX C) 100Base-FX D) none of the above

30. ________ uses fiber-optic cable. A) 10Base2 B) 10Base-F C) 10Base-T D) 10Base5

31. In Ethernet addressing, if the least significant bit of the first byte is 0, the address is _________.

A) broadcast B) multicast C) unicast D) none of the above

32. ________ uses 1550-mm single mode fiber. A) 10GBase-E B) 10GBase-S C) 10GBase-L D) none of the above

33. 1000Base-T uses ________ line coding. A) MLT-3 B) 4D-PAM5 C) Manchester D) 8B6T

34. The maximum frame length for 10-Mbps Ethernet is ________ bytes. A) 1200 B) 1518 C) 1500 D) none of the above

35. The minimum frame length for 10-Mbps Ethernet is _______bytes. A) 128 B) 80 C) 32 D) none of the above

36. __________uses two optical fibers and a long-wave laser source. A) 1000Base-T B) 1000Base-SX C) 1000Base-LX D) none of the above

37. The _______ layer of Ethernet consists of the LLC sublayer and the MAC sublayer. A) network B) data link C) physical D) none of the above

38. 100Base-FX uses _________ block coding and ________ line coding. A) 8B/10B; NRZ B) 4B/5B; MLT-3 C) 8B/10B; NRZ D) 4B/5B; NRZ-I

39. Which of the following could not be an Ethernet unicast destination? A) 46:56:21:1A:DE:F4 B) 43:7B:6C:DE:10:00 C) 48:32:21:21:4D:34 D) 44:AA:C1:23:45:32

40. _________ uses thick coaxial cable. A) 10Base2 B) 10Base5 C) 10Base-F D) 10Base-T

41. The IEEE 802.3 Standard defines _________ CSMA/CD as the access method for first-generation 10-Mbps Ethernet.

A) non-persistent B) p-persistent C) 1-persistent D) none of the above

42. _________ uses four twisted-pair cables that connect each station to a common hub. A) 10Base-F B) 10Base-T C) 10Base5 D) 10Base2

CHAPTER-14

WIRELESS LANS

1. The original IEEE 802.11, has a data rate of _____Mbps. A) 11 B) 22 C) 6 D) 1

2. In IEEE 802.11, when a frame is going from a station to an AP, the address flag is _____. A) 01 B) 10 C) 11 D) 00

3. In IEEE 802.11, when a frame is going from one station in a BSS to another without passing through the distribution system, the address flag is _____.

A) 11 B) 00 C) 10 D) 01

4. In IEEE 802.11, the access method used in the PCF sublayer is ______. A) polling B) controlled C) contention D) none of the above

5. In IEEE 802.11, a BSS without an AP is called an _________. A) an infrastructure network B) an ad hoc architecture C) either (a) or (b) D) neither (a) nor (b)

6. In IEEE 802.11, the addressing mechanism can include up to ______addresses. A) six B) five C) four D) none of the above

7. In Bluetooth, the _______ layer is roughly equivalent to the physical layer of the Internet model.

A) baseband B) radio C) L2CAP D) none of the above

8. In IEEE 802.11, a station with ________ mobility is either stationary (not moving) or moving only inside a BSS.

A) ESS-transition B) no-transition C) BSS-transition D) none of the above

9. In Bluetooth, the L2CAP sublayer, is roughly equivalent to the LLC sublayer in LANs. A) baseband B) L2CAP

C) radio D) none of the above

10. In IEEE 802.11, when a frame is going from one AP to another AP in a wireless distribution system, the address flag is _____.

A) 10 B) 01 C) 11 D) 00

11. A Bluetooth network is called a ________. A) scatternet B) bluenet C) piconet D) none of the above

12. A Bluetooth network consists of _____ primary device(s) and up to ____ secondary devices. A) one; seven B) one; five C) five; three D) two; six

13. In Bluetooth, the current data rate is ____Mbps. A) 11 B) 5 C) 2 D) none of the above

14. In IEEE 802.11, a BSS with an AP is sometimes referred to as ____________. A) an infrastructure network B) an ad hoc architecture C) either (a) or (b) D) neither (a) nor (b)

15. In IEEE 802.11, the ______ is a timer used for collision avoidance. A) BSS B) ESS C) NAV D) none of the above

16. In IEEE 802.11, the MAC layer frame has ______ fields. A) four B) six C) five D) none of the above

17. Bluetooth uses ______method in the physical layer to avoid interference from other devices or other networks.

A) FHSS B) DSSS C) FDMA D) none of the above

18. In Bluetooth, the _____ link is used when data integrity is more important than avoiding latency.

A) SCL B) ACO C) ACL D) SCO

19. In Bluetooth, the _____layer is roughly equivalent to the MAC sublayer in LANs. A) L2CAP B) radio C) baseband D) none of the above

20. IEEE has defined the specifications for a wireless LAN, called _______, which covers the physical and data link layers.

A) IEEE 802.5 B) IEEE 802.11 C) IEEE 802.2 D) IEEE 802.3

21. In IEEE 802.11, a station with ________ mobility can move from one ESS to another. A) BSS-transition B) ESS-transition C) no-transition D) none of the above

22. The IEEE 802.11g, uses _________. A) DSSS B) OFDM C) FHSS D) either (a) or (c)

23. In IEEE 802.11, the access method used in the DCF sublayer is _________. A) CSMA/CA B) CSMA/CD C) ALOHA D) none of the above

24. The RTS and CTS frames in CSMA/CA ____ solve the hidden station problem. The RTS and CTS frames in CSMA/CA ____ solve the exposed station problem.

A) cannot; cannot B) can; cannot C) cannot; can D) can; can

25. In IEEE 802.11, communication between two stations in two different BSSs usually occurs via two ________.

A) ESSs B) APs C) BSSs D) none of the above

26. Bluetooth is a _______ technology that connects devices (called gadgets) in a small area. A) VLAN B) wired LAN C) wireless LAN D) none of the above

27. The original IEEE 802.11, uses _________. A) FHSS B) OFDM C) DSSS D) either (a) or (c)

28. The IEEE 802.11a, uses _________. A) DSSS B) OFDM C) FHSS D) either (a) or (c)

29. In IEEE 802.11, a ___ is made of stationary or mobile wireless stations and an optional central base station, known as the access point (AP).

A) BSS B) CSS C) ESS D) none of the above

30. The IEEE 802.11 standard for wireless LANs defines two services: ______ and _______. A) ESS; SSS B) BSS; ESS C) BSS; ASS D) BSS; DCF

31. In Bluetooth, the _____ link is used when avoiding latency (delay in data delivery) is more important than integrity (error-free delivery).

A) SCL B) ACL C) ACO D) SCO

32. IEEE 802.11b, has a data rate of _____Mbps. A) 5.5 B) 2 C) 1 D) none of the above

33. IEEE 802.11g, has a data rate of _____Mbps. A) 22 B) 11 C) 2 D) 1

34. In IEEE 802.11, a station with ________mobility can move from one BSS to another, but the movement is confined inside one ESS.

A) ESS-transition B) no-transition C) BSS-transition D) none of the above

35. The access method in Bluetooth is ________. A) TDD-TDMA B) CDMA C) FDMA D) none of the above

36. The IEEE 802.11 wireless LANs use ________ types of frames. A) five B) six C) four D) none of the above

37. In IEEE 802.11, _______ is an optional access method that can be implemented in an infrastructure network (not in an ad hoc network).

A) PCF B) DCF C) either (a) or (b) D) neither (a) nor (b)

38. In IEEE 802.11, when a frame is coming from an AP and going to a station, the address flag is _______.

A) 00 B) 11 C) 10 D) 01

39. In Bluetooth, multiple ________ form a network called a _________. A) piconets: bluenet B) scatternet; piconets C) piconets: scatternet D) bluenet; scatternet

40. The IEEE 802.11b, uses _________. A) OFDM B) FHSS C) DSSS D) either (a) or (b)

41. IEEE 802.11a, has a data rate of _____Mbps. A) 6 B) 2 C) 1 D) none of the above

CHAPTER-15

CONNECTING LANS, BACKBONE NETWORKS AND VIRTUAL LANS

1. VLANs create _________ domains. A) multicast B) broadcast C) unicast D) none of the above

2. A ________ operates in both the physical and the data link layer. A) router B) bridge C) repeater D) passive hub

3. A _______ is a device that operates only in the physical layer. A) bridge B) router C) passive hub D) repeater

4. A ______ switch is a faster and more sophisticated router. A) two-layer B) four-layer

C) three-layer D) none of the above

5. _________ is just a connector. A) A passive hub B) An active hub C) either (a) or (b) D) neither (a) nor (b)

6. A ______ normally connects LANs and WANs in the Internet and has a table that is used for making decisions about the route.

A) router B) bridge C) repeater D) none of the above

7. A repeater is a connecting device that operates in the _______

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