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.