CIS 4348 Chapter 4
The simplest method for error correction is retransmission. (True or False)
True
____________ is not a function of a data link protocol.
Amplitude shift keying
Which of the following is not a controlled access method of media access control?
CSMA/CD
Another term for stop-and-wait ARQ is sliding window. (True or False)
False
Which of the following media is least susceptible to noise?
fiber optic cable
_____________ is an effective way to prevent attenuation.
Adding repeaters or amplifiers to a circuit
Most computer networks managed by a host mainframe computer use contention media access control.(True or False)
False
Parity checking can only detect an error when an even number of bits are switched. (True or False)
False
Polling is the process of permitting all clients to transmit or receive at any time. (True or False)
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. (True or False)
False
The two categories of network errors are: lost data and delimited data. (True or False)
False
Transmission efficiency refers to the percentage of bits transmitted without errors. (True or False)
False
With contention, a computer does not have to wait before it can transmit. A computer can transmit at anytime. (True or False)
False
______________ controls errors by detecting and correcting them at the receiving end without retransmission of the original message.
Hamming code
Which of the following is true with respect to the data link layer?
It performs error detection.
_____________ is an effective way to prevent impulse noise, cross talk, and intermodulation noise.
Shielding wires
If a computer transmits a message containing "ABC" and the destination computer receives "abc" as the message, the message is corrupted. (True or False)
True
Media access controls refer to the need to control when computers transmit. (True or False)
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 or False)
True
Undesirable stray electrical voltage can cause data communication errors. (True or 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 or False)
True
When we amplify the signal on an analog circuit, we also amplify any noise that is present on the circuit. (True or False)
True
With roll-call polling, a server polls clients in a consecutive, pre-arranged priority list. (True or False)
True
Which of the following is not a type of synchronous protocol?
VT100
With contention:
computers wait until the circuit is free before they send data
Stop-and-wait ARQ uses ___________ type of data flow.
half duplex
Contention is commonly used with Ethernet local area networks. (True or False)
True
Controlled access MAC approaches work better in a large network with high usage. (True or False)
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 or False)
True
Cyclical redundancy check is one of the most popular polynomial error-checking schemes. (True or False)
True
Forward error correction is commonly used in satellite transmission. (True or False)
True
The probability of detecting an error, given that one has occurred, using parity checking is about:
50%
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?
00011011
Data transmission errors are typically uniformly distributed in time. (True or False)
False
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.
TRIB, an acronym that relates to throughput, stands for:
Transmission Rate of Information Bits
Attenuation refers to the loss of signal strength. (True or False)
True
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 loss of power a signal suffers as it travels from the transmitting computer to a receiving computer is:
attenuation
Errors on a network can occur:
because of noise on the line
In a _________ , more than one data bit is changed by the error-causing condition.
burst error
Asynchronous transmission:
each character is transmitted independently of all other characters
Media access control:
is not very important in point-to-point with full duplex configuration
Which of the following is true about the data link protocol, PPP?
it is commonly used in WANs
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 true about the data link protocol, Ethernet (IEEE 802.3)?
newer version permits jumbo frames
On digital circuits, we use _________ to reshape the incoming signal and prevent attenuation.
repeaters
Another term for impulse noise is:
spikes
The primary source of error in data communications is:
spikes
As part of the five-layer network model used in this textbook, the data link layer sits directly between:
the physical and the network layers
Synchronous transmission:
uses start bits before each character to be sent
The familiar background static on radios and telephones is called:
white noise
In general, controlled approaches:
work better than contention approaches for large networks that have high usage