MIS 140- Chapter4
As part of the five-layer network model used in this textbook, the data link layer sits directly between: the physical and the application layers the network and the application layers the network and transport layers the physical and the application layers the physical and the network layers
the physical and the network layers
As part of the five-layer network model used in this textbook, the data link layer sits directly between: The physical and the application layers. The network and the application layers. The network and transport layers. The physical and the application layers. The physical and the network layers.
the physical and the network layers.
Harmonic distortion can be prevented by tuning equipment moving wires increasing guardbands increasing signal strength using a high-speed circuit
tuning equipment
The familiar background static on radios and telephones is called: echoes intermodulation noise impulse noise cross-talk white noise
white noise
The familiar background static on radios and telephones is called: echoes intermodulation noise impulse noise cross-talk white noise
white noise
With odd parity (assume that the parity bit (in bold) has been placed at the end of each of the following) and a 7-bit ASCII code, which of the following is incorrect? 01101011 00011011 00100101 10110110 11111110
00011011
The probability of detecting an error, given that one has occurred, using parity checking is about: 100% 0% 50% 75% 98%
50%
The probability of detecting an error, provided that one has occurred, using cyclic redundancy checking is about: 75% 0% exactly 100% 50% > 99%
> 99%
The probability of detecting an error, provided that one has occurred, using cyclic redundancy checking is about: 75% 0% exactly 100% 50% > 99%
> 99%
he probability of detecting an error, provided that one has occurred, using cyclic redundancy checking is about: 75% 0% exactly 100% 50% > 99%
> 99%
Using parity, the probability for detecting an error, given that one has occurred, is: About 50% for either even or odd parity. About 70% for even parity and 30% for odd parity. About 30% for even parity and 70% for odd parity. About 0% for either even or odd parity. About 100% for either even or odd parity.
About 50% for either even or odd parity.
_____________ is an effective way to prevent attenuation. Shielding wires Adding fluorescent lights Adding repeaters or amplifiers to a circuit Changing multiplexing techniques Shorting a circuit
Adding repeaters or amplifiers to a circuit
_____________ is an effective way to prevent attenuation. Shielding wires Adding fluorescent lights Adding repeaters or amplifiers to a circuit Changing multiplexing techniques Shorting a circuit
Adding repeaters or amplifiers to a circuit
___________ is not a function of a data link protocol. Media access control. Message delineation. Amplitude shift keying. Indicating when a message starts and stops. Error control.
Amplitude shift keying
____________ is not a function of a data link protocol.
Amplitude shift keying
____________ is not a function of a data link protocol. Media access control Message delineation Amplitude shift keying Indicating when a message starts and stops Error control
Amplitude shift keying
Which of the following is not a controlled access method of media access control?
CSMA/CD
Which of the following is not a controlled access method of media access control? Token passing CSMA/CD polling roll call polling hub polling
CSMA/CD
Which of the following is way to reduce or eliminate crosstalk on a circuit. Changing multiplexing techniques. Adding repeaters or amplifiers to a circuit. Reducing the length of the cable. Adding fluorescent lights. Shorting a circuit.
Changing multiplexing techniques.
Another term for stop-and-wait ARQ is sliding window.
False
Data transmission errors are typically uniformly distributed in time. True False
False
Gaussian noise is a special type of attenuation. True False
False
Impulse noise is caused by the thermal agitation of electrons.
False
In an odd parity-checking scheme, the parity bit is set to make the total number of ones in the byte (including the parity bit) an even number. True False
False
Most computer networks managed by a host mainframe computer use contention media access control. True False
False
Only the sender of a data transmission needs to be concerned about the rules or protocols that govern how it communicates with the receiver. True False
False
Parity checking can only detect an error when an even number of bits are switched.
False
Polling is the process of permitting all clients to transmit or receive at any time.
False
The distance between repeaters or amplifiers on a telephone circuit is determined by the amount of power gained per unit length of the transmission.
False
Transmission efficiency refers to the percentage of bits transmitted without errors. True False
False
With contention, a computer does not have to wait before it can transmit. A computer can transmit at any time. True False
False
With contention, a computer does not have to wait before it can transmit. A computer can transmit at anytime.
False
____________ refers to bits that have been changed, in error, from 1 to 0, or vice versa, in a data transmission.
Flipped bits
____________ refers to bits that have been changed, in error, from 1 to 0, or vice versa, in a data transmission. Contracted bits Polled bits Inverse multiplexed bits Flipped bits Bit delineation
Flipped bits
______________ controls errors by detecting and correcting them at the receiving end without retransmission of the original message. Hamming code Huffman encoding Front end processing Wave division multiplexing Hub polling
Hamming code
__________can obliterate a group of bits, causing a burst error. Cross-talk Attenuation Impulse noise Intermodulation noise White noise
Impulse noise
__________can obliterate a group of bits, causing a burst error. Cross-talk Attenuation Impulse noise Intermodulation noise White noise
Impulse noise
If a signal with a frequency of 500 MHz combines with another signal of 1500 MHz and they form a new signal of 2000 MHz; this is an example of: Intermodulation noise attenuation echo white noise cross-talk
Intermodulation noise
Which of the following is true with respect to the data link layer? It accepts streams of bits from the application layer. It is responsible for getting a message from one computer to another (one node to another) without errors. It does not perform error detection. It performs routing functions. It organizes data from the physical layer and passes these coherent messages to the application layer.
It is responsible for getting a message from one computer to another (one node to another) without errors.
Which of the following is true with respect to the data link layer? It accepts streams of bits from the application layer. It is responsible for encoding the bit-stream as a series of electronic voltages. It performs error detection. It performs routing functions. It organizes data from the physical layer and passes these coherent messages directly to the application layer.
It performs error detection.
Which of the following is true about roll call polling?
It typically involves some waiting because the server has to wait for a response from the polled client or terminal.
Which of the following is true about roll call polling? It can not be modified to increase priority of clients or terminals. It does not require a server or host or special device that performs the polling. It is also called token passing. It is a type of contention approach to media access control. It typically involves some waiting because the server has to wait for a response from the polled client or terminal.
It typically involves some waiting because the server has to wait for a response from the polled client or terminal.
Which of the following is true about the data link protocol, SDLC: It is a client-server protocol developed by Compaq in 1996. It transmits each character independently of one another and includes start and stop bits for each character sent. It uses a special bit pattern called a flag at the beginning and end of every frame (or packet). It uses a contention media access control protocol and is used in most LANs today. It does not have any error detection capabilities.
It uses a contention media access control protocol and is used in most LANs today.
Optical media is: More likely to suffer from noise than electrical media. Has about the same likelihood of suffering from noise as electrical media. Has about the same likelihood of suffering from noise as coaxial cable. Less likely to suffer from noise than electrical media. More prone to noise than twisted pair media.
Less likely to suffer from noise than electrical media.
The two sublayers of the data link layer consist of the media access control sublayer and the________ .
Logical link control sublayer
Which of the following is way to reduce or eliminate crosstalk on a circuit? Physically separating the cables from other communication cables. Adding repeaters or amplifiers to a circuit. Reducing the length of the cable. Adding fluorescent lights. Shorting a circuit.
Physically separating the cables from other communication cables.
________ is the process of sending a signal to a client that gives its permission to transmit or asks it to receive. Contention Polling Pooling Carrier sense CRC
Polling
________ is the process of sending a signal to a client that gives its permission to transmit or asks it to receive. Contention Polling Pooling Carrier sense CRC
Polling
_____________ is an effective way to prevent impulse noise, cross talk, and intermodulation noise. Shielding wires Adding fluorescent lights Adding repeaters to a circuit Adding amplifiers to a circuit Shorting a circuit
Shielding wires
Attenuation refers to the loss of signal strength.
TRUE
TRIB, an acronym that relates to throughput, stands for:
Transmission Rate of Information Bits
TRIB, an acronym that relates to throughput, stands for: Throughput Reduction of Information Barriers. Transmission Rate of Information Bits. Throughput Rate of Iso-synchronous Bytes Transmission Regulation for Inverse-multiplexing Bands. Trellis-coded Regulation of Information Bits.
Transmission Rate of Information Bits.
_________________ is defined as the total number of information bits divided by the total number of bits in the transmission. Asynchronous rate Protocol percentage Throughput Transmission Rate of Information Bits Transmission efficiency
Transmission efficiency
Contention is commonly used with Ethernet local area networks. True False
True
Controlled access MAC approaches work better in a large network with high usage.
True
Crosstalk occurs when the signal transmitted on one circuit or channel of a transmission system creates an undesired effect in another circuit or channel. True False
True
Cyclical redundancy check is one of the most popular polynomial error-checking schemes. True False
True
For effective error detection and correction, extra error detection "data" must be included with each message
True
Forward error correction is commonly used in satellite transmission.
True
Forward error correction is commonly used in satellite transmission. True False
True
Forward error correction is commonly used in satellite transmission. True False
True
HDLC is very similar to the SDLC synchronous data link protocol.
True
If a computer transmits a message containing "ABC" and the destination computer receives "abc" as the message, the message is corrupted. True False
True
If a computer transmits a message containing "ABC" and the destination computer receives "abc" as the message, the message is corrupted. True False
True
Media access controls refer to the need to control when computers transmit. True False
True
One type of forward error correction is the Hamming code. True False
True
Overhead bits are used for error checking and marking the start and end of characters and packets. True False
True
The data link layer accepts messages from the network layer and controls the hardware that transmits them. True False
True
The physical and data link layers of wired Ethernet have been refined over the years as a collection of standards under the IEEE 802.3 workgroup. True False
True
The simplest method for error correction is retransmission.
True
Token passing is a term that refers to hub polling, in which one computer starts a poll and passes it to the next computer on a multipoint circuit.
True
Token passing is a term that refers to hub polling, in which one computer starts a poll and passes it to the next computer on a multipoint circuit. True False
True
Undesirable stray electrical voltage can cause data communication errors. True False
True
When the signals from two circuits combine to form a new signal that falls into a frequency band reserved for another signal, this is called intermodulation noise.
True
When we amplify the signal on an analog circuit, we also amplify any noise that is present on the circuit. True False
True
With roll-call polling, a server polls clients in a consecutive, pre-arranged priority list.
True
With roll-call polling, a server polls clients in a consecutive, pre-arranged priority list. True False
True
Which of the following is not a type of synchronous protocol? SDLC VT100 HDLC Ethernet PPP
VT100
ARQ means that: A receiver that detects an error in a message simply asks the sender to retransmit the message until it is received without error. The common carrier Automatically Returns Queries to the subscriber upon receipt of such queries. A sender is using a data link protocol called Asynchronous Repeating reQuest. A fiber optic cable meets the American Registered Quality, a certification standard for use in high-quality data communication transmission lines. A sender is using a parity scheme called Array Resource Quality.
a receiver that detects an error in a message simply asks the sender to retransmit the message until it is received without error.
The loss of power a signal suffers as it travels from the transmitting computer to a receiving computer is: white noise spiking attenuation intermodulation noise echo
attenuation
Errors on a network can occur: only on dial-up type of circuits. because of noise on the line. only on poorly maintained networks. only due to Gaussian noise. only due to lightning strikes.
because of noise on the line.
In a _________ , more than one data bit is changed by the error-causing condition. burst error. data rate shift. Trellis-coded modulation. uniform distribution. amplitude key shift.
burst error
Calculating the actual throughput of a data communication network is:
complex because many factors affect throughput
Calculating the actual throughput of a data communication network is: Not normally required for synchronous networks because they are so fast. Complex because many factors affect throughput. Simple because packet size is the primary factor affecting throughput. Not needed for satellite-based networks. Far less complicated if the system operates on a contention basis.
complex because many factors affect throughput.
Calculating the actual throughput of a data communication network is: Not normally required for synchronous networks because they are so fast. complex because many factors affect throughput. simple because packet size is the primary factor affecting throughput. not needed for satellite-based networks. far less complicated if the system operates on a contention basis.
complex because many factors affect throughput.
With contention: computers wait until the circuit is free before they send data. the server or front-end processor works consecutively through a list of clients to determine who should have access to the media. the front-end processor must wait for a response from the polled client or terminal. one computer starts the poll and passes it to the next computer on the multipoint circuit. there is never a chance for "collision," or two computers trying to send data at the same time.
computers wait until the circuit is free before they send data.
With __________ ARQ, the sender immediately sends the next message or packet of data. continuous immediate open window stop-and-wait halt and be recognized (HBR)
continuous
Asynchronous transmission: is used to transmit each character simultaneously with all other characters has a pre-determined, fixed time between sending characters is typically used on multipoint half duplex circuits uses a continuous series of start bits as an idle signal each character is transmitted independently of all other characters
each character is transmitted independently of all other characters
When a signal is reflected back to the transmitting equipment, it is called a(n) _________. white noise echo crosstalk attenuation impulse noise
echo
Which of the following media is least susceptible to noise? fiber optic cable coaxial cable twisted pair unshielded twisted pair shielded twisted pair
fiber optic cable
Stop-and-wait ARQ uses ___________ type of data flow. full simplex half complex full duplex half duplex full complex
half duplex
When the output signal from an amplifier on a circuit is different from the input signal, this is called _________________. intermodulation noise attenuation echo jitter harmonic distortion
harmonic distortion
In communication protocols, _________ are used to convey the user's meaning. information bits overhead bits stop bits start bits flag bits
information bits
If a signal with a frequency of 500 MHz combines with a another signal of 1500 MHz and they form a new signal of 2000 MHz; this is an example of intermodulation noise attenuation echo jitter harmonic distortion
intermodulation noise
Media access control:
is not very important in point-to-point with full duplex configuration
In ARQ, a NAK: is sent by the recipient if the message was received without error. is sent by the sender at the same time as it sends a data packet. is sent by the recipient if the message contains an error. refers to the non-asynchronous Kermit technique. means that the sender should continue with sending the next message.
is sent by the recipient if the message was received without error
Synchronous transmission: cannot be used on multipoint circuits. is used to send one character at a time. uses start bits before each character to be sent. uses stop bits after each character to be sent. is used to transmit a "frame" or "packet" of data at a time.
is used to transmit a "frame" or "packet" of data at a time
Which of the following is true about the data link protocol, PPP? it is commonly used in WANs it is a bit-oriented protocol it uses block-check characters for error detection it was developed in the 1960s it uses parity bits for error detection
it is commonly used in WANs
Optical media is: More likely to suffer from noise than electrical media. Has about the same likelihood of suffering from noise as electrical media. Has about the same likelihood of suffering from noise as coaxial cable. Less likely to suffer from noise than electrical media. More prone to noise than twisted pair media.
less likely to suffer from noise than electrical media.
The two sublayers of the data link layer consist of the media access control sublayer and the________ . logical link control sublayer. network control sublayer. session sublayer. physical sublayer. transport sublayer. A
logical link control sublayer
Which of the following is true about the data link protocol, Ethernet (IEEE 802.3)? It is not very popular. It is a bit-oriented protocol. It uses block check characters for error detection. The newer version permits jumbo frames. It uses parity bits for error detection.
newer version permits jumbo frames.
Cross-talk: Occurs when one circuit picks up signals in another. Is always bothersome because it has a high signal strength. Decreases with increased proximity of two wires. Decreases during wet or damp weather. Increases with lower frequency signals.
occurs when one circuit picks up signals in another.
Which of the following is not an error detection method used in the data link layer? parity checking cyclic redundancy checking CRC-32 pulse code checking odd parity
pulse code checking
On digital circuits, we use _________ to reshape the incoming signal and prevent attenuation. amplifiers repeaters multiplexers digitizers modems
repeaters
Another term for impulse noise is: Gaussian noise spikes attenuation cross-talk intermodulation noise
spikes
The primary source of error in data communications is: echoes intermodulation noise spikes attenuation cross-talk
spikes
The primary source of error in data communications is: echoes intermodulation noise spikes attenuation cross-talk
spikes
With __________ ARQ, the sender pauses for a response from the receiver to alter each message or packet of data.
stop and wait
