Chapter 4: Data Link Layer

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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?

Hamming Code

_____ controls errors by detecting and correcting them at the receiving end without retransmission of the original message.

HDLC (High-level Data Link Control)

_____ has essentially replaced SDLC and offers a larger sliding window.

MAC Address Spoofing

_____ is a software-enabled technique that can change the hardcoded MAC address to any MAC address and thus overcome MAC address filtering.

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.

Transmission Efficiency

_____ is defined as the total number of information bits divided by the total number of bits in the transmission.

In ARQ, a NAK

_____ is sent by the recipient if the message contains an error

Spikes

_____ is the primary source of error in data communications.

Polling

_____ is the process of sending a signal to a client that gives its permission to transmit or asks it to receive.

Synchronous Transmission

_____ is used to transmit a "frame" or "packet" of data at a time.

Cross-talk

_____ occurs when one circuit picks up signals in another.

Flipped bits

_____ refers to bits that have been changed, in error, from 1 to 0, or vice versa, in a data transmission.

In general, controlled approaches

_____ works better than contention approaches for large networks that have high usage.

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:

Burst Error

In a _________, more than one data bit is changed by the error-causing condition.

Information Bits

In communication protocols, _____ are used to convey the user's meaning.

50%

The probability of detecting an error, given that one has occurred, using parity checking is about:

> 99%

The probability of detecting an error, provided that one has occurred, using cyclic redundancy checking is about:

Logical Link Control Sublayer

The two sublayers of the data link layer consist of the media access control sublayer and the ________.

about 50% for either even or odd parity

Using parity, the probability for detecting an error, given that one has occurred, is _____.

Echo

When a signal is reflected back to the transmitting equipment, it is called a(n) _____.

CSMA/CD

Which of the following is not a controlled access method of media access control?

VT100

Which of the following is not a type of synchronous protocol?

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?

complex because many factors affect throughput

Calculating the actual throughput of a data communication network is _____.

Repeaters

On digital circuits, we use _____ to reshape the incoming signal and prevent attenuation.

Amplitude Shift Keying (ASK)

_____ is not a function of a data link protocol.

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.

With Contention

computers wait until the circuit is free before they send data.

Media Access Control (MAC)

is not very important in point-to-point with full-duplex configuration.

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.

Asynchronous Transmission

With _____, each character is transmitted independently of all other characters.

MAC Address

The data link layer uses the ________ to recognize the source and destination addresses.

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:

The 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 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?

It performs error detection.

Which of the following is true with respect to the data link layer?

physically separating the cables from other communication cables

Which of the following is way to reduce or eliminate crosstalk on a circuit?

Fiber-Optic Cable

Which of the following media is least susceptible to noise?