Ch. 4 - MIS 564
Spikes
Another term for impulse noise is:
True
Attenuation refers to the loss of signal strength
Occurs when one circuit picks up signals in another
Cross-talk:
is sent by the recipient if the message contains an error
In ARQ, a NAK:
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.
Information bits
In communication protocols, _________ are used to convey the user's meaning
False
In data transmission, data errors are uniformly distributed in time.
False
Polling is the process of permitting all clients to transmit or receive at any time
is used to transmit a "frame" or "packet" of data at a time
Synchronous transmission:
True
The data link layer accepts messages from the network layer and controls the hardware that transmits them
White noise
The familiar background static on radios and telephones is called:
attenuation
The loss of power a signal suffers as it travels from the transmitting computer to a receiving computer is:
True
The simplest method for error correction is retransmission.
True
For effective error detection and correction, extra error detection "data" must be included with each message.
about 50% for either even or odd parity
Using parity, the probability for detecting an error, given that one has occurred, is:
pulse code checking
Which of the following is not an error detection method used in the data link layer?
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 is commonly used in WANs
Which of the following is true about the data link protocol, PPP?
It uses a special bit pattern called a flag at the beginning and end of every frame (or packet)
Which of the following is true about the data link protocol, SDLC:
fiber optic cable
Which of the following media is least susceptible to noise?
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?
complex because many factors affect throughput
Calculating the actual throughput of a data communication network is:
True
Contention is commonly used with Ethernet local area networks.
is not very important in point-to-point with full duplex configuration
Media access control:
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
Parity checking can only detect an error when an even number of bits are switched
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.
False
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.
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 aplifiers to a circuit
_____________ is an effective way to prevent attenuation.
Transmission efficiency
_________________ is defined as the total number of information bits divided by the total number of bits in the transmission.
