Midterm exam

Question 1

What is the binary equivalent of decimal number 75?

Answer 1

1001011

Question 2

213 to hexa

Answer 2

D5

Question 3

ED to decimal

Answer 3

237

Question 4

143 to binary

Answer 4

100011111

Question 5

187 to hexa

Answer 5

BB

Question 6

BD to decimal

Answer 6

189

Question 7

195 to binary

Answer 7

11000011

Question 8

What is the purpose of the OSI physical layer?

Answer 8

Transmitting bits across the local media

Question 9

Which characteristics describes crosstalk?

Answer 9

the distortion of the transmited messages from signals carried in adjacent wires

Question 10

A network administrator is measuring the transfer of bits across the company backbone for a mission application. The administrator notices that the network throuhput appears lower than the bandwidth.

Answer 10

the amount of traffic that is currently crossing the network

Question 11

Which of the following is a characteristic of fiber-optic cable?

Answer 11

It is not affected by EMI or RFI

Question 12

What is a primary role of the Physical layer in transmitting data on the network?

Answer 12

create the signals that represent the bits in each frame on the media

Question 13

With the use of unshielded twisted-pair copper wire in a network, what causes crosstalk within the cable pairs?

Answer 13

The magnetic field around the adjacent pairs of wire

Question 14

In addition to the cable length, what factor could interfere with the communication carried over UTP cables??

Answer 14

Crosstalk

Question 15

Which of the following devices commonly affect wireless networks

Answer 15

microwaves

Question 16

Which of the following statements describe the services provided by the data link layer

a. It defines the end-to-end delivery addressing scheme

b. It maintains the path between the source and destination devices during the data trainsmission

c. It manages the access of frames to the network media

d. It provides reliable delivery through link establishment and flow control

e. It ensures that application data will be transmitted according to the prioritization

Answer 16

C. it manages the access of frames to the network media

Question 17

Wha is the function of the CRC value that is found in the FCS field of a frame?

Answer 17

to verify the integrity of the received frame

Question 18

What is contained in the trailer of a data-link frame?

Answer 18

error detection

Question 19

Which statements describes a characteristic of the frame header fields of the data link layer?

Answer 19

They vary depending on protocols

Question 20

A network team is comparing physical WAN topologies for connecting remote sites to a headquarters building. Which topology provides high availability and connects some, but not all, remote sites?

Answer 20

partial mesh

Question 21

Which fields or features does Ethernet examine to determine if a received frame is passed to the data link layer or discarded by the NIC

Answer 21

Frame Check Sequence

Question 22

Which media communication type does not require media arbitration in the data link layer>?

Answer 22

Full duplex

Question 23

Which statement describes an extended star topology?

a. End devices connect to a central intermediate device, which in turn connects to other central intermediate devices.

b. End devices are connected together by a bus and each bus connects to a central intermediate device.

c. Each end system is connected to its respective neighbor via an intermediate device.

d. All end and intermediate devices are connected in a chain to each other.

Answer 23

a. End devices connect to a central intermediate device, which in turn connects to other central intermediate devices.

Question 24

What is a characteristic of the LLC sublayer?

a. It provides the logical addressing required that identifies the device.

b. It provides delimitation of data according to the physical signaling requirements of the medium.

c. It places information in the frame allowing multiple Layer 3 protocols to use the same network interface and media.

d. It defines software processes that provide services to the physical layer.

Answer 24

c. It places information in the frame allowing multiple Layer 3 protocols to use the same network interface and media.

Question 25

What are three ways that media access control is used in networking? (Choose three.) a. Ethernet utilizes CSMA/CD. b. Media access control provides placement of data frames onto the media. c. Contention-based access is also known as deterministic. 802.11 utilizes CSMA/CD. d. Data link layer protocols define the rules for access to different media. e. Networks with controlled access have reduced performance due to data collisions.

Answer 25

a. Ethernet utilizes CSMA/CD. b. Media access control provides placement of data frames onto the media. d. Data link layer protocols define the rules for access to different media.

Question 26

During the encapsulation process, what occurs at the data link layer for a PC connected to an Ethernet network? a. An IP address is added. b. The logical address is added. c. The physical address is added. d. The process port number is added

Answer 26

c. The physical address is added.

Question 27

What three items are contained in an Ethernet header and trailer? (Choose three.) a. source IP address b. source MAC address c. destination IP address d. destination MAC address e. error-checking information

Answer 27

d. destination MAC address e. error-checking information b. source MAC address

Question 28

What type of commuinication rule would best describe CSMA/CD?

Answer 28

Access method

Question 29

What are the basic parts that are common to all frame types supported by data link layer

Answer 29

- Header - Data - Trailer

Question 30

Which statement is true about the CSMA/CD access method that is used in Ethernet? a. When a device hears a carrier signal and transmits, a collision cannot occur. b. A jamming signal causes only devices that caused the collision to execute a backoff algorithm. c. All network devices must listen before transmitting. d. Devices involved in a collision get priority to transmit after the backoff period.

Answer 30

c. All network devices must listen before transmitting.

Question 31

Which frame forwarding method receives the entire frame and performs a CRC check to detect errors before forwarding the frame? a. cut-through switching b. store-and-forward switching c. fragment-free switching d. fast-forward switching

Answer 31

b. store-and-forward switching

Question 32

What is the purpose of the FCS field in a frame? a. to obtain the MAC address of the sending node b. to verify the logical address of the sending node c. to compute the CRC header for the data field d. to determine if errors occurred in the transmission and reception

Answer 32

d. to determine if errors occurred in the transmission and reception

Question 33

When the store-and-forward method of switching is in use, what part of the Ethernet frame is used to perform an error check? a. CRC in the trailer b. source MAC address in the header c. destination MAC address in the header d. protocol type in the header

Answer 33

a. CRC in the trailer

Question 34

Which two statements describe features or functions of the logical link control sublayer in Ethernet standards? (Choose two.) a. Logical link control is implemented in software. b. Logical link control is specified in the IEEE 802.3 standard. c. The LLC sublayer adds a header and a trailer to the data. d. The data link layer uses LLC to communicate with the upper layers of the protocol suite. e. The LLC sublayer is responsible for the placement and retrieval of frames on and off the media.

Answer 34

a. Logical link control is implemented in software. d. The data link layer uses LLC to communicate with the upper layers of the protocol suite.