Chapter 4( ITN 100)
spikes
Another term for impulse noise is:
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:
True
Attenuation refers to the loss of signal strength.
occurs when one circuit picks up signals in another
Cross-talk:
True
Cyclical redundancy check is one of the most popular polynomial error-checking schemes.
intermodulation noise
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:
is sent by the recipient if the message contains an error
In ARQ, a NAK:
True
In a network, the type of errors caused during data transmission can be controlled by the network hardware and software.
information bits
In communication protocols, _________ are used to convey the user's meaning.
work better than contention approaches for large networks that have high usage
In general, controlled approaches:
True
Point-to-point Protocol is a byte-count-oriented protocol.
half duplex
Stop-and-wait ARQ uses ___________ type of data flow.
Transmission Rate of Information Bits
TRIB, an acronym that relates to throughput, stands for:
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.
Logical link control
The first sublayer of the data link layer is the
spikes
The primary source of error in data communications is:
50%
The probability of detecting an error, given that one has occurred, using parity checking is about:
False
The two categories of network errors are: lost data and delimited data.
True
Forward error correction is commonly used in satellite transmission.
True
HDLC is very similar to the SDLC synchronous data link protocol.
about 50% for either even or odd parity
Using parity, the probability for detecting an error, given that one has occurred, is:
cross-talk
When the output signal from an amplifier on a circuit is different from the input signal, this is called _________________.
True
When we amplify the signal on an analog circuit, we also amplify any noise that is present on the circuit.
VT100
Which of the following is not a type of synchronous protocol?
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?
newer version permits jumbo frames
Which of the following is true about the data link protocol, Ethernet (IEEE 802.3)?
it is commonly used in WANs
Which of the following is true about the data link protocol, PPP?
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?
changing multiplexing techniques
Which of the following is way to reduce or eliminate crosstalk on a circuit,
continuous
With __________ ARQ, the sender immediately sends the next message or packet of data.
stop and wait
With __________ ARQ, the sender pauses for a response from the receiver to alter each message or packet of data.
False
With contention, a computer does not have to wait before it can transmit. A computer can transmit at anytime.
computers wait until the circuit is free before they send data
With contention:
00011011
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?
True
With roll-call polling, a server polls clients in a consecutive, pre-arranged priority list.
True
Contention is commonly used with Ethernet local area networks.
True
Ethernet has been refined over the years and is now formally standardized as IEEE802.3ac.
True
Media access controls refer to the need to control when computers transmit.
repeaters
On digital circuits, we use _________ to reshape the incoming signal and prevent attenuation.
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
Overhead bits are used for error checking and marking the start and end of characters and packets.
Fasle
Transmission efficiency refers to the percentage of bits transmitted without errors.
Polling
________ is the process of sending a signal to a client that gives its permission to transmit or asks it to receive.
Amplitude shift keying
____________ is not a function of a data link protocol.
Flipped bits
____________ refers to bits that have been changed, in error, from 1 to 0, or vice versa, in a data transmission.
Adding repeaters or amplifiers to a circuit
_____________ is an effective way to prevent attenuation.
Shielding wires
_____________ is an effective way to prevent impulse noise, cross talk, and intermodulation noise.
Hamming code
______________ controls errors by detecting and correcting them at the receiving end without retransmission of the original message.
Transmission efficiency
_________________ is defined as the total number of information bits divided by the total number of bits in the transmission.
Impulse noise
__________can obliterate a group of bits, causing a burst error.