Question 1

The physical and data link layers of wired Ethernet have been refined over the years as a collection of standards under the IEEE 802.3 workgroup.

Accepted Answer

This statement is true. The IEEE 802.3 workgroup is responsible for developing and refining the standards for the physical (layer 1) and data link (layer 2) layers of wired Ethernet.

Question 2

Attenuation refers to the loss of signal strength.

Accepted Answer

Attenuation is the reduction of signal strength over distance or through a medium, so it is true that attenuation refers to the loss of signal strength.

Question 3

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.

Accepted Answer

When signals from two circuits mix, they can produce new frequencies that fall within the frequency range of other signals, causing interference known as intermodulation noise.

Question 4

With contention, a computer does not have to wait before it can transmit.A computer can transmit at anytime.

Accepted Answer

Contention-based systems allow multiple devices to share the same communication medium, but devices must contend or compete for access, potentially waiting if the medium is busy to avoid data collisions.

Question 5

With roll-call polling, a server polls clients in a consecutive, pre-arranged priority list.

Accepted Answer

With roll-call polling, the server polls clients in a consecutive, pre-arranged priority list.

Question 6

Contention is commonly used with Ethernet local area networks.

Accepted Answer

Contention is a common method used to manage access to the network in Ethernet LANs. It is a form of medium access control where devices on the network contend for access to the shared communication medium.

Question 7

Impulse noise is caused by the thermal agitation of electrons.

Accepted Answer

Impulse noise is caused by sudden interference or disturbances in the signal, typically from external sources such as electromagnetic radiation or faulty electrical equipment. It is not caused by thermal agitation of electrons.

Question 8

Gaussian noise is a special type of attenuation.

Accepted Answer

Gaussian noise refers to a type of signal distortion where random variations are added to the signal, resulting in a probability distribution that follows the Gaussian or normal distribution. It is not a form of attenuation, which refers to the reduction in amplitude or power of a signal during transmission or propagation.

Question 9

Crosstalk occurs when the signal transmitted on one circuit or channel of a transmission system creates an undesired effect in another circuit or channel.

Accepted Answer

Crosstalk is when there is unwanted interference between separate channels or circuits in a transmission system. It can cause distortion, noise, or signal degradation.

Question 10

Undesirable stray electrical voltage can cause data communication errors.

Accepted Answer

Stray electrical voltage can interfere with data communication signals, causing errors and disruptions in the transmission of information. Electrical noise and interference can be caused by a variety of sources, including power lines, electronic devices, and environmental factors such as lightning and atmospheric disturbances. It is important to take steps to minimize the effects of stray electrical voltage on communication systems, such as using shielding and grounding techniques, and ensuring that electrical devices are properly designed and installed.

Question 11

The two categories of network errors are: lost data and delimited data.

Accepted Answer

The two categories of network errors are not lost data and delimited data. The two categories of network errors are transmission errors and routing errors.

Question 12

Media access controls refer to the need to control when computers transmit.

Accepted Answer

Media access controls, such as CSMA/CD and token passing, are designed to regulate when computers can transmit data on a shared network to avoid collisions and ensure efficient communication.

Question 13

Most computer networks managed by a host mainframe computer use contention media access control.

Accepted Answer

Most computer networks managed by a host mainframe typically use a deterministic media access control method, such as token passing or polling, rather than contention-based methods, to ensure orderly and reliable communication.

Question 14

Polling is the process of permitting all clients to transmit or receive at any time.

Accepted Answer

Polling is a technique used in computer networking where a central device (usually a hub, switch or router) sends out a request or "poll" to individual devices (nodes or clients) on the network, asking if they need to transmit any data. Only one device may transmit at a time, and all others must wait until their turn. Therefore, polling does not permit all clients to transmit or receive at any time.

Question 15

Controlled access MAC approaches work better in a large network with high usage.

Accepted Answer

Controlled access MAC approaches, such as token passing or reservation protocols, are designed to manage and coordinate access to the network in a controlled manner. These approaches work better in large networks with high usage because they prevent collisions and ensure that all nodes have equal opportunity to transmit data. In smaller networks with low usage, other MAC approaches such as contention-based protocols may be more effective.

Question 16

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.

Accepted Answer

Token passing involves passing a token or permission signal around a network in a predetermined order for devices to transmit data, whereas hub polling involves the hub sending out requests for data to connected devices. They are not the same thing.

Question 17

Data transmission errors are typically uniformly distributed in time.

Accepted Answer

Data transmission errors are not uniformly distributed in time. They can occur randomly or be influenced by factors such as network congestion, distance, and interference.

Question 18

Only the sender of a data transmission needs to be concerned about the rules or protocols that govern how it communicates with the receiver.

Accepted Answer

Both the sender and receiver need to be aware of and comply with the rules or protocols in order to successfully communicate with each other. Failure to follow these rules can result in errors or a failed transmission.

Question 19

The data link layer accepts messages from the network layer and controls the hardware that transmits them.

Accepted Answer

This statement is true. The data link layer is responsible for accepting messages from the network layer and preparing them for transmission across the physical network. It also controls the hardware, such as network interface cards (NICs), that are used to transmit the messages.

Question 20

If a computer transmits a message containing "ABC" and the destination computer receives "abc" as the message, the message is corrupted.

Accepted Answer

The message has been altered in some way, resulting in a corruption of the data. In this case, the capitalization of the letters has been changed, which is a form of corruption.

Quiz 4: Data Link Layer