1.
An administrator measured the transfer of usable data across a 100 Mb/s physical channel over a given period of time and obtained 60 Mb/s. Which kind of measurement did the administrator obtain?
Correct Answer
C. Goodput
Explanation
Refer to curriculum topic: 4.1.3
Goodput is the measure of usable data transferred over a given period of time. It is the throughput minus traffic overhead for establishing sessions, acknowledgments, and encapsulation. Throughput is the measure of the transfer of bits across the media over a given period of time. Digital bandwidth measures the amount of information that can flow from one place to another in a given amount of time. Latency is a measure of time delay that is experienced in a network.
2.
Fill in the blank.In fiber optic media, the signals are represented as patterns of ________.
Correct Answer
Light
Explanation
Refer to curriculum topic: 4.1.2
In fiber optic media, the physical layer produces the representation and groupings of bits as patterns of light.
3.
What is the purpose of the physical link control field in a data link layer header?
Correct Answer
C. To establish the media link
Explanation
Refer to curriculum topic: 4.4.4
Physical link control, flow control, and congestion control are possible fields that may be found in certain frames. The physical link control field is used to establish the media link. The logical connection control field is used to establish a logical connection between nodes. The flow control field is used to start and stop traffic over the media, and the congestion control field is used to indicate congestion in the media.
4.
What is a characteristic of a WAN hub-and-spoke topology?
Correct Answer
D. The branch sites are connected to a central site through point-to-point links.
Explanation
Refer to curriculum topic: 4.4.2
A hub-and-spoke topology is a WAN version of the star topology in which a central site interconnects branch sites using point-to-point links. A mesh topology requires that every end system be interconnected to every other system using point-to-point links. A partial mesh is a variation of this topology, where some but not all end devices are interconnected. There is no topology where all the sites have to have hub devices that are connected to a router.
5.
When is a wired connection preferred to a wireless connection by an end-user device?
Correct Answer
C. When the end-user device will run an application that requires a dedicated connection to the network
Explanation
Refer to curriculum topic: 4.1.1
Examples of when an end-user device would prefer a wired connection include when the device is not within range of a wireless signal, when the device only has an Ethernet NIC, or when the device requires a dedicated connection because of the performance requirements of the application. A wired connection would be also be required for non-delay tolerant applications.
6.
Which is a function of the Logical Link Control (LLC) sublayer?
Correct Answer
C. To identify which network layer protocol is being used
Explanation
Refer to curriculum topic: 4.3.1
Defining the media access processes that are performed by the hardware and providing data link layer addressing are functions of the MAC sublayer. The data link layer accepts Layer 3 packets and packages them into data units that are called frames.
7.
Which two factors influence the method that is used for media access control? (Choose two.)
Correct Answer(s)
B. How the connection between nodes appears to the data link layer
D. How nodes share the media
Explanation
Refer to curriculum topic: 4.4.1
The media access control method used depends on the topology (how the connection between the nodes appears to the data link layer), and how the nodes share the media. The type of data generated by end devices applications, the way signals are encoded by the NICs on end devices, and even the way the IP protocol forwards the packet through the network have no influence on the choice of the method used for media access control.
8.
Which two engineering organizations define open standards and protocols that apply to the data link layer? (Choose two.)
Correct Answer(s)
A. International Organization for Standardization (ISO)
C. International Telecommunications Union (ITU)
Explanation
Refer to curriculum topic: 4.3.3
The IANA is responsible for overseeing and managing IP address allocation, domain name management, and protocol identifiers. The EIA is an international standards and trade alliance for electronics organizations, and is best known for its standards related to electrical wiring, connectors, and the 19-inch racks used to mount networking equipment. The ISOC promotes the open development, evolution, and use of the Internet throughout the world.
9.
Which statement describes a characteristic of the frame header fields of the data link layer?
Correct Answer
C. They vary depending on protocols.
Explanation
Refer to curriculum topic: 4.4.4
All data link layer protocols encapsulate the Layer 3 PDU within the data field of the frame. However, the structure of the frame and the fields that are contained in the header vary according to the protocol. Different data link layer protocols may use different fields, like priority/quality of service, logical connection control, physical link control, flow control, and congestion control.
10.
Which two statements are true of the deterministic access method? (Choose two.)
Correct Answer(s)
A. The throughput is predictable.
C. Devices take turns transmitting.
Explanation
Refer to curriculum topic: 4.4.3
In a controlled access method, network devices take turns, in sequence, to access the media. If an end device does not have any data to transmit, then the opportunity passes to the next end device. If one end device places a frame on the media, no other device can do so until the frame has arrived at the destination and has been processed by the destination. It is a non-collision, well-ordered method and provides predictable throughput. However, it can be inefficient, because a device has to wait for its turn before it can use the medium.
11.
Refer to the image. One end of the cable is terminated as displayed, and the other end is terminated in accordance with the T568A standard. What type of cable would be created in this manner?
Correct Answer
C. Straight-through
Explanation
Refer to curriculum topic: 4.2.2
A crossover cable has a T568A standard termination at one end and a T568B standard at the other end. A rollover cable can have either a T568A or T568B standard termination at one end, and at the other end have the same standard, but with the wires connected in reverse order. A straight-through cable can have either a T568A or T568B standard termination at one end and the same at the other end. A fiber-optic cable is not terminated using RJ-45 connectors.