Question 1

Another term for impulse noise is:

Accepted Answer

A)  Gaussian noise 
B)  spikes 
C)  attenuation 
D)  cross-talk 
E)  intermodulation noise 
A)  Gaussian noise 
B)  spikes 
C)  attenuation 
D)  cross-talk 
E)  intermodulation noise B

Question 2

Describe three approaches to detecting errors,including how they work,the probability of detecting an error,and any other benefits or limitations.

Accepted Answer

1. Checksums: This approach involves adding up all the data in a message and sending the result along with the message. The receiver then recalculates the checksum and compares it to the one sent. If they match, the data is assumed to be error-free. The probability of detecting an error with checksums is high, but it is not foolproof as it can miss certain types of errors. However, it is a simple and efficient method for detecting errors in data transmission.

2. Redundancy: Redundancy involves adding extra bits to the data being transmitted so that errors can be detected and corrected. One common method is the use of parity bits, where an extra bit is added to each byte of data to ensure that the total number of ones in the byte is always even or odd. This allows the receiver to detect if an error has occurred. The probability of detecting an error with redundancy is high, and it also allows for error correction in some cases. However, it requires additional bandwidth and can be more complex to implement.

3. Cyclic Redundancy Check (CRC): CRC is a more sophisticated error detection method that involves generating a fixed-size checksum based on the data being transmitted. The receiver then recalculates the checksum and compares it to the one sent. If they match, the data is assumed to be error-free. The probability of detecting an error with CRC is very high, and it is also capable of detecting a wider range of errors compared to simpler methods like checksums. However, it is more complex to implement and requires more computational resources.

In conclusion, each of these approaches to error detection has its own benefits and limitations. Checksums are simple and efficient but not foolproof, redundancy allows for error correction but requires additional bandwidth, and CRC is highly effective but more complex to implement. The choice of method depends on the specific requirements and constraints of the data transmission system.

Question 3

With __________ ARQ,the sender pauses for a response from the receiver to alter each message or packet of data.

Accepted Answer

A)  open window 
B)  halt and be recognized (HBR) 
C)  sliding window 
D)  stop and wait 
E)  continuous 
A)  open window 
B)  halt and be recognized (HBR) 
C)  sliding window 
D)  stop and wait 
E)  continuous D

Question 4

Which of the following is true about roll call polling?

Accepted Answer

A)  It can not be modified to increase priority of clients or terminals. 
B)  It does not require a server or host or special device that performs the polling. 
C)  It is also called token passing. 
D)  It is a type of contention approach to media access control. 
E)  It typically involves some waiting because the server has to wait for a response from the polled client or terminal. 
A)  It can not be modified to increase priority of clients or terminals. 
B)  It does not require a server or host or special device that performs the polling. 
C)  It is also called token passing. 
D)  It is a type of contention approach to media access control. 
E)  It typically involves some waiting because the server has to wait for a response from the polled client or terminal.

Question 5

With contention,a computer does not have to wait before it can transmit.A computer can transmit at anytime.

Accepted Answer

A) True 
 B)False

Question 6

The probability of detecting an error,given that one has occurred,using parity checking is about:

Accepted Answer

A)  100% 
B)  0% 
C)  50% 
D)  75% 
E)  98% 
A)  100% 
B)  0% 
C)  50% 
D)  75% 
E)  98%

Question 7

On digital circuits,we use _________ to reshape the incoming signal and prevent attenuation.

Accepted Answer

A)  amplifiers 
B)  repeaters 
C)  multiplexers 
D)  digitizers 
E)  modems 
A)  amplifiers 
B)  repeaters 
C)  multiplexers 
D)  digitizers 
E)  modems

Question 8

What does the data link layer do? What are its primary responsibilities? Where does the data link layer sit in terms of the simplified five layer network model?

Accepted Answer

The answer of What does the data link layer do?...

Question 9

The first sublayer of the data link layer is the

Accepted Answer

A)  logical link control sublayer 
B)  media access control sublayer 
C)  session sublayer 
D)  physical sublayer 
E)  transport sublayer 
A)  logical link control sublayer 
B)  media access control sublayer 
C)  session sublayer 
D)  physical sublayer 
E)  transport sublayer

Question 10

Which of the following is not an error detection method used in the data link layer?

Accepted Answer

A)  parity checking 
B)  cyclic redundancy checking 
C)  CRC-32 
D)  pulse code checking 
E)  odd parity 
A)  parity checking 
B)  cyclic redundancy checking 
C)  CRC-32 
D)  pulse code checking 
E)  odd parity

Question 11

The probability of detecting an error,provided that one has occurred,using cyclic redundancy checking is about:

Accepted Answer

A)  75% 
B)  0% 
C)  exactly 100% 
D)  50% 
E)  > 99% 
A)  75% 
B)  0% 
C)  exactly 100% 
D)  50% 
E)  > 99%

Question 12

What is transparency?

Accepted Answer

Transparency, in a general context, refe

Question 13

Only the sender of a data transmission needs to be concerned about the rules or protocols that govern how it communicates with the receiver

Accepted Answer

A) True 
 B)False

Question 14

How does forward error correction work? How is it different from other error correction methods? Under what circumstances is forward error correction desirable? What is one type of forward error correction by name?Given a diagram like that in the text of forward error correction,be able to explain how the system works.

Accepted Answer

Forward error correction (FEC) is a meth

Question 15

_____________ is an effective way to prevent attenuation.

Accepted Answer

A)  Shielding wires 
B)  Adding fluorescent lights 
C)  Adding repeaters or amplifiers to a circuit 
D)  Changing multiplexing techniques 
E)  Shorting a circuit 
A)  Shielding wires 
B)  Adding fluorescent lights 
C)  Adding repeaters or amplifiers to a circuit 
D)  Changing multiplexing techniques 
E)  Shorting a circuit

Question 16

In communication protocols,_________ are used to convey the user's meaning.

Accepted Answer

A)  information bits 
B)  overhead bits 
C)  stop bits 
D)  start bits 
E)  flag bits 
A)  information bits 
B)  overhead bits 
C)  stop bits 
D)  start bits 
E)  flag bits

Question 17

Stop-and-wait ARQ uses ___________ type of data flow.

Accepted Answer

A)  full simplex 
B)  half complex 
C)  full duplex 
D)  half duplex 
E)  full complex 
A)  full simplex 
B)  half complex 
C)  full duplex 
D)  half duplex 
E)  full complex

Question 18

The simplest method for error correction is retransmission.

Accepted Answer

A) True 
 B)False

Question 19

In a _________ ,more than one data bit is changed by the error-causing condition.

Accepted Answer

A)  burst error 
B)  data rate shift 
C)  Trellis-coded modulation 
D)  uniform distribution 
E)  amplitude key shift 
A)  burst error 
B)  data rate shift 
C)  Trellis-coded modulation 
D)  uniform distribution 
E)  amplitude key shift

Question 20

Forward error correction is commonly used in satellite transmission.

Accepted Answer

A) True 
 B)False

Another term for impulse noise is:

Describe three approaches to detecting errors,including how they work,the probability of detecting an error,and any other benefits or limitations.

With __________ ARQ,the sender pauses for a response from the receiver to alter each message or packet of data.

Which of the following is true about roll call polling?

With contention,a computer does not have to wait before it can transmit.A computer can transmit at anytime.

The probability of detecting an error,given that one has occurred,using parity checking is about:

On digital circuits,we use _________ to reshape the incoming signal and prevent attenuation.

What does the data link layer do? What are its primary responsibilities? Where does the data link layer sit in terms of the simplified five layer network model?

The first sublayer of the data link layer is the

Which of the following is not an error detection method used in the data link layer?

The probability of detecting an error,provided that one has occurred,using cyclic redundancy checking is about:

What is transparency?

Only the sender of a data transmission needs to be concerned about the rules or protocols that govern how it communicates with the receiver

_____________ is an effective way to prevent attenuation.

In communication protocols,_________ are used to convey the user's meaning.

Stop-and-wait ARQ uses ___________ type of data flow.

The simplest method for error correction is retransmission.

In a _________ ,more than one data bit is changed by the error-causing condition.

Forward error correction is commonly used in satellite transmission.

Introduction to Data Communications

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Network and Transport Layers

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Exam 4: Data Link Layer

Another term for impulse noise is:

Describe three approaches to detecting errors,including how they work,the probability of detecting an error,and any other benefits or limitations.

With __________ ARQ,the sender pauses for a response from the receiver to alter each message or packet of data.

Which of the following is true about roll call polling?

With contention,a computer does not have to wait before it can transmit.A computer can transmit at anytime.

The probability of detecting an error,given that one has occurred,using parity checking is about:

On digital circuits,we use _________ to reshape the incoming signal and prevent attenuation.

What does the data link layer do? What are its primary responsibilities? Where does the data link layer sit in terms of the simplified five layer network model?

The first sublayer of the data link layer is the

Which of the following is not an error detection method used in the data link layer?

The probability of detecting an error,provided that one has occurred,using cyclic redundancy checking is about:

What is transparency?

Only the sender of a data transmission needs to be concerned about the rules or protocols that govern how it communicates with the receiver

_____________ is an effective way to prevent attenuation.

In communication protocols,_________ are used to convey the user's meaning.

Stop-and-wait ARQ uses ___________ type of data flow.

The simplest method for error correction is retransmission.

In a _________ ,more than one data bit is changed by the error-causing condition.

Forward error correction is commonly used in satellite transmission.

Introduction to Data Communications

Application Layer

Physical Layer

Network and Transport Layers

Wired and Wireless LANs

Backbone Networks

Wide Area Networks

The Internet

Network Security

Network Design

Network Management

Filters