23. A network administrator is troubleshooting connectivity issues on a server. Using a tester, the
administrator notices that the signals generated by the server NIC are distorted and not usable. In
which layer of the OSI model is the error categorized?
The NIC has responsibilities in both Layer 1 and Layer 2. The NIC encodes the frame as a series of signals that are transmitted onto the local media. This is the responsibility of the physical layer of the OSI model. The signal could be in the form of electrical, optical, or radio waves.
24. What type of cable is used to connect a workstation serial port to a Cisco router console port?
UTP cable wire pairs can be terminated in different configurations for use in
different applications. To use a UTP cable for consoling into a Cisco router from a PC serial
port, it must be terminated as a rollover or console cable.
25. Why are two strands of fiber used for a single fiber optic connection?
A. The two strands allow the data to travel for longer distances without degrading.
B. They prevent crosstalk from causing interference on the connection.
C. They increase the speed at which the data can travel.
In copper cables, crosstalk is a disturbance caused by the electric or magnetic fields
of a signal on one wire interfering with the signal in an adjacent wire. Twisting opposing circuit
wire pairs together can effectively cancel the crosstalk. The other options are effective measures
to counter the negative effects of EMI and RFI, but not crosstalk.
27. What is one advantage of using fiber optic cabling rather than copper cabling?
A. It is usually cheaper than copper cabling.
B. It is able to carry signals much farther than copper cabling.
C. It is easier to terminate and install than copper cabling.
When the end-user devices need mobility to connect to the network, wireless is
recommended. If an end-user device only has an Ethernet NIC, the user will only be able to use
Ethernet cabling. If RFI is an issue, wireless is not recommended. An end-user device that
requires a dedicated connection for performance would perform better with a dedicated Ethernet
29. Which type of UTP cable is used to connect a PC to a switch port?
A rollover cable is a Cisco proprietary cable used to connect to a router or switch
console port. A straight-through (also called patch) cable is usually used to interconnect a host to
a switch and a switch to a router. A crossover cable is used to interconnect similar devices
together, for example, between two switches, two routers, and two hosts.
30. What is the definition of bandwidth?
A. The speed of bits across the media over a given period of time
B. The measure of usable data transferred over a given period of time
C. The amount of data that can flow from one place to another in a given amount of time
Bandwidth is the measure of the capacity of a network medium to carry data. It is
the amount of data that can move between two points on the network over a specific period of
time, typically one second.
31. Which statement correctly describes frame encoding?
A. It generates the electrical, optical, or wireless signals that represent the binary numbers of the frame.
B. It converts bits into a predefined code in order to provide a predictable pattern to help distinguish data bits from control bits.
C. It uses the characteristic of one wave to modify another wave.
D. It transmits data signals along with a clock signal which occurs at evenly spaced time durations.
Frame encoding converts a stream of data bits into a predefined code that is
recognized by both the sender and receiver. These codes are used for a variety of purposes, such
as distinguishing data bits from control bits, and identifying the beginning and end of a frame.
Cladding and immunization from electrical hazards are characteristics for fiber-
optic cabling. A woven copper braid or metallic foil is used as a shield for the inner coaxial cable
conductor. Cancellation is a property of UTP cabling where two wires are located adjacent to one
another so each magnetic field cancels out the adjacent magnetic field.
33. A wireless LAN is being deployed inside the new one room office that is occupied by the park
ranger. The office is located at the highest part of the national park. After network testing is
complete, the technicians report that the wireless LAN signal is occasionally affected by some
type of interference. What is a possible cause of the signal distortion?
A. The elevated location where the wireless LAN was installed
B. The number of wireless devices that are used in the wireless LAN
C. The large number of trees that surround the office
Wireless LAN connectivity is not affected by trees or the elevation of the
equipment. Because this is a one room office in an isolated area, there will not be a large number
of wireless devices or source of interference operating in the immediate vicinity. The use of a
microwave oven could result in signal interference.
34. What is the purpose of the OSI physical layer?
A. Controlling access to mediaireless LAN was installed
B. Exchanging frames between nodes over physical network media
The physical layer is responsible for transmitting the actual signals across the
physical media as bits. Exchanging frames, controlling media access, and performing error
detection are all functions of the data link layer.
35. Which characteristic describes crosstalk?
A. The weakening of the network signal over long cable lengths
B. The loss of wireless signal over excessive distance from the access point
C. The distortion of the network signal from fluorescent lighting
D. The distortion of the transmitted messages from signals carried in adjacent wires
EMI and RFI can distort network signals because of interference from fluorescent
lights or electric motors. Attenuation results in deterioration of the network signal as it travels
along copper cabling. Wireless devices can experience loss of signals because of excessive
distances from a access point, but this is not crosstalk. Crosstalk is the disturbance caused by the
electric or magnetic fields of the signal carried on an adjacent wire within the same cable.
36. What is indicated by the term throughput?
A. The time it takes for a message to get from sender to receiver
B. The measure of the bits transferred across the media over a given period of time
C. The measure of the usable data transferred across the media
D. The guaranteed data transfer rate offered by an ISP
Throughput is the measure of the transfer of bits across the media over a given
period of time. Throughput is affected by a number of factors such as, EMI and latency, so it
rarely matches the specified bandwidth for a network medium. The throughput measurement
includes user data bits and other data bits, such as overhead, acknowledging, and encapsulation.
The measure of the usable data transferred across the media is called goodput.
37. Which standards organization oversees development of wireless LAN standards?
IANA oversees the management of IP address allocation and domain names. ISO is
the largest developer of international networking standards and is famous for the Open Systems
Interconnection (OSI) model. TIA focuses on communication standards. The IEEE 802 standards
are many, but the ones that affect an entry-level network professional are Ethernet (802.3),
wireless LANs (802.11), and wireless PANs (802.15).