WorksheetsOSI Layers and Data Link Layer Worksheet
Total questions: 97
Worksheet time: 49mins
Which OSI layer includes cables and connectors?
physical
application
presentation
transport
network
The Data Link Layer provides:
reliable transfer of information across physical link
sends frames for sync, error, and flow control
transmission of unstructured bitstream
mechanical/electrical characteristics
At the data link layer:
interface between devices and bits
activation, control, deactivation of link
transfer end-to-end
dialog between applications
Which layer is above the physical layer?
data
data link
network
transport
Which layer controls data flow so receiver is not overwhelmed?
data link
network
presentation
session
The data link layer is responsible for:
flow control
error control
access control
all of the above
Which layer retransmits damaged frames?
network
session
data link
presentation
On which layer does the trailer usually contain error-detecting bits?
network
session
transport
data link
Which layer provides error and flow control between sender–receiver?
physical
data link
transport
network
Important to remember for peer-to-peer communication in the data link layer:
encapsulates frames into packets
connects data to transport
frame header contains physical address
encapsulates network info into frames
provides service to network layer
On which layer is the NIC located?
physical
data link
network
transport
The Network Layer provides:
independence of higher layers from routing tech
establishing, maintaining, terminating connections
reliable transparent data transfer
end-to-end recovery
At the network layer:
interface between devices
activation/control of link
transfer of info through networks
exchange between end points
application dialog
Which layer is responsible for packet delivery (including through multiple networks)?
network
session
transport
data link
The network layer header includes ____ addresses of sender & receiver.
logical
ports
physical
network
Which layer provides routing mechanisms?
network
session
transport
data link
The ____ address changes when a packet moves between networks, the ____ does not.
logical; port
logical; network
logical; physical
physical; logical
Which layer is responsible for delivering a single packet from the message?
physical
data link
transport
network
The transport layer uses services of the ____ layer.
data link
network
session
none
Which is NOT a responsibility of the transport layer?
end-to-end delivery
node-to-node error checking
error control
all of the above
The Transport Layer provides:
reliable transparent end-to-end transport
end-to-end error recovery & flow control
independence from routing technologies
establish/manage/terminate connections
At the transport layer:
interface between devices
activation/control of link
transfer through networks
exchange of data between end systems
dialogs between applications
Which layer provides reliable data transmission?
network
physical
data link
transport
Which layer is responsible for delivery of the entire message?
physical
data link
transport
network
Reassembling packets into the original message is the job of:
physical
data link
transport
network
Dividing a message into packets is done at which layer?
physical
data link
transport
network
Which is NOT a duty of the transport layer?
multiplexing
reliable delivery
routing
all are duties
Communication between two transport layers is called:
peer-to-peer
physical
link
none
The Application Layer in the OSI model provides:
user access to the OSI environment
control structure for communications
control of data transfer
In the OSI model, the application layer deals with:
transfer of information between end systems through a network
communication between application programs and the OSI environment
data exchange between end systems
interface between two devices and the bits being transmitted
activation, management, and deactivation of the link
File transfer is the task of which layer?
application
presentation
session
transport
E-mail is a service in which layer?
session
presentation
application
data link
The main protocol used for sending e-mail is:
SMTP
SNMP
FTP
none of the above
Which of the following protocols operate at the application layer of the OSI model?
FTP
TCP
UDP
HTTP
Each layer consists of:
protocol specification
service definition
addressing
RAM memory
processor
The N-th layer sends service to the layer numbered:
N+1
N-1
N+2
N-2
The N-th layer receives service from the layer numbered:
N+1
N-1
N+2
N-2
The data link layer separates a sequence of bits received from the network layer into:
segments
frames
datagrams
messages
The application, presentation, and session layers in OSI correspond to which TCP/IP layer?
application
session
data link
transport
Which layers appear in both OSI and TCP/IP models but have different functions?
transport
session
application
internet
physical
Which model is used to better understand the communication process of data?
OSI model
IEEE model
In what way are TCP/IP and OSI models the same?
both have a physical layer
both simulate circuit-switched networks
both have Network Access + Data Link layers
both have similar transport and network layers
both simulate packet-switched networks
How many layers does TCP/IP consist of?
2
3
5
7
In the TCP/IP protocol, the layer above the transport layer is called:
session
presentation
application
none of the above
What does TCP do to start the three-way handshake?
the destination computer sends an ACK segment
the initiating computer sends a SYN segment
the initiating computer sends SYN + ACK
the destination computer sends a SYN segment
Which TCP/IP layer is responsible for dialogue control?
application
presentation
session
transport
Which OSI layers correspond to the Network Access layer in TCP/IP?
physical layer
session layer
network layer
data link layer
application layer
Which layer is considered the host-to-network layer in TCP/IP?
presentation
transport
network access
data link
internet
Which TCP/IP layer provides services that support logical communication between the sending and receiving hosts?
network
transport
presentation
session
Which of the following terms are correctly defined?
A transmission path, A transmission medium, A receiver
A sender, A protocol, A switch
A router, A repeater, A hub
A cable, A connector, A modem
According to the direction in which data is transmitted, data transmission can be
simplex, duplex
parallel, serial
analog, digital
synchronous, asynchronous
Electromagnetic signals have the following characteristics: • In a discrete electromagnetic signal, intensity changes at a constant time period • In a discrete electromagnetic signal, shape changes at a constant time period • For a continuous electromagnetic signal the intensity is constant without interruptions during transmission — actually continuous means no discrete steps, not constant intensity • In a periodic electromagnetic signal the shape repeats at a certain period. Which of the following statements is correct?
In a discrete electromagnetic signal, intensity changes at a constant time period; In a discrete electromagnetic signal, shape changes at a constant time period; In a periodic electromagnetic signal the shape repeats at a certain period
In a continuous electromagnetic signal, intensity changes at random intervals; In a discrete electromagnetic signal, shape is always constant; In a periodic electromagnetic signal the shape never repeats
In a discrete electromagnetic signal, intensity is always constant; In a continuous electromagnetic signal, shape changes at a constant time period; In a periodic electromagnetic signal the intensity repeats at a certain period
In a periodic electromagnetic signal, intensity is constant; In a discrete electromagnetic signal, shape never changes; In a continuous electromagnetic signal, intensity changes at a constant time period
Which of the following relations hold during data transmission?
Greater data transmission of a signal means larger bandwidth of the transmission system; With smaller bandwidth the chances of errors increase
Greater data transmission of a signal means smaller bandwidth of the transmission system; With larger bandwidth the chances of errors increase
Greater data transmission of a signal means larger bandwidth of the transmission system; With larger bandwidth the chances of errors increase
Greater data transmission of a signal means smaller bandwidth of the transmission system; With smaller bandwidth the chances of errors increase
Which of the following statements is true about transmission cost and bandwidth?
Transmission cost is directly proportional to the bandwidth
Transmission cost is inversely proportional to the bandwidth
Transmission cost does not depend on bandwidth
Usually analogue data is represented by analogue signals and digital data by digital signals. But it is possible
Using a modem to represent analogue data with digital signals
Using a codec to represent analogue data with digital signals
Using a modem to represent digital data with analogue signals
Using a codec to represent digital data with analogue signals
Which of the following statements are true for analogue transmission
Analogue transmission is used for transmitting analogue and digital signals
The analogue signal is transmitted independently of the data it represents
Signal strength decreases after a certain distance; serially connected repeaters are used
Amplifying a signal results in an error if digital data is being transmitted
Which of the following statements are true for digital transmission
Digital transmission is used for transmitting analogue and digital signals
Digital transmission does not depend on the content of the signal
Repeaters are used for long-distance digital signal transmission
Amplifiers are used for long-distance digital transmission
Digital signal can be transmitted over any distance without degradation
When a signal is transmitted its strength decreases. For the strength of the received signal
The signal level must be lower than the noise level for error-free reception
Attenuation of the signal is an increasing function of the signal frequency
Attenuation is a decreasing function of frequency
In wired media signal strength decreases linearly with distance
In wireless media signal strength decreases logarithmically with distance
Depending on the cause, the noise types are
thermal noise
intermodulation noise
impulse noise
nonlinear noise
interference noise
Which of the following are possible values for human voice frequency?
300 Hz
7000 Hz
100 Hz
10 Hz
3400 Hz
For data transmission the following are needed:
sender
receiver
transmission medium
modem
control medium
Transmission media are divided into:
guided
unguided
semiconductor
digital
Examples of guided media:
Optical fiber
Coaxial cable
Air
Vacuum
Twisted pair
Examples of unguided media:
Sea water
Vacuum
Twisted pair
Coaxial cable
Air
Data transmission can be:
half duplex
full duplex
full simplex
half simplex
simplex
Which charge combinations repel each other?
neutral and neutral
neutral and negative
negative and negative
neutral and positive
positive and positive
What happens when a voltage source is connected to a complete electric circuit?
electrons flow from the negative terminal to the positive terminal
current decreases
resistance increases
resistance decreases
electrons flow from positive to negative
In which unit is electric current measured?
ampere
volt
ohm
watt
kilowatt
Which materials strictly do not allow electron flow?
silicon-based materials
ionic solutions
conductors
semiconductors
insulators
In simplex transmission:
signals are transmitted in only one direction
signals are transmitted in many directions
signals are transmitted only in two directions
In half-duplex transmission:
both devices can be transmitters, but only one at a given moment
both devices can transmit simultaneously
signals travel in many directions
only one device can be a transmitter, the other a receiver
In full-duplex transmission:
both devices can transmit simultaneously
both can transmit, but only one at a time
only one can transmit, the other receives
signals travel in many directions
Characteristics of half-duplex:
Only one station can transmit at a time; Requires one data line
Both stations can transmit simultaneously; Requires two data lines
Only one station can receive at a time; Requires wireless connection
Multiple stations can transmit at the same time; Requires fiber optic cable
Characteristics of full-duplex:
Simultaneous sending and receiving; Requires two data lines (or echo canceling)
Only one-way communication at a time; Uses a single data line
Data can only be sent, not received; No data line required
Communication is always half-duplex; Requires manual switching
In which mode can every station transmit, but not all at once?
simplex
half-duplex
duplex
half-duplex and duplex
Which system is an example of half-duplex?
keyboard
walkie-talkie
In which mode can two stations send and receive simultaneously?
simplex
half-duplex
duplex (full-duplex)
half-duplex and duplex
Which system is an example of duplex?
keyboard
radio receiver
telephone network
repeater
Which expression describes full-duplex communication?
traffic goes in one direction without collisions
traffic is faster downstream than upstream
traffic flows equally in both directions without collisions
traffic is faster upstream than downstream
A direct link is:
a link where there are no intermediate devices between sender and receiver
can be used with both guided and unguided media
used only with guided media
used only with unguided media
a link between the sender and a router
A transmission path is point-to-point if:
it provides a direct connection between two devices and they are the only ones sharing the medium
provides a direct connection, but they are not the only devices sharing the medium
provides a direct connection between multiple devices
does not provide a direct connection
Point-To-Point can be:
guided medium
coaxial cable
connection between two multi-point stations
A multi-point connection exists if:
multiple devices share the same medium
uses a multi-access protocol
only two devices share the same medium
An aperiodic signal is a signal where:
the same shape does not repeat over time
the same shape repeats over time
the intensity is always at one constant level
Phase is:
the relative position of the signal with respect to time
the time for one repetition of the signal
the speed at which the signal repeats
directly proportional to frequency f
If we need to connect two parts of a 10BASE5 LAN because the signal is too weak, we need a:
repeater
bridge
router
port
The amplitude of a signal can be measured in:
volts
amperes
watts
All of the above
Which of the following describes amplitude?
the height of each wave
the length of each wave
the number of waves per second
the time length between waves
Which of the following is true about square waves?
They represent digital signals.
They repeat the same shape at equal time intervals.
They change continuously with time.
They occur naturally and vary regularly over time.
They do not change continuously with time.
A periodic signal is a signal where:
the same shape repeats over time
the intensity stays at the same level
the same shape does not repeat over time
A sinusoidal wave can be represented by which parameters?
maximum amplitude
frequency
phase
periodic signal
discrete signal
673. Period (T):
is the time for one repetition of a signal
is the amplitude of a signal
is the frequency of a signal
is the phase of a signal
Which of the following is inversely proportional to the frequency?
is inversely proportional to the frequency
is equal to the frequency
is the product of frequency and time
is directly proportional to frequency
A _____ signal repeats continuously.
Digital
Analog
Periodic
Aperiodic
The frequency of a signal is inversely proportional to the:
amplitude
period
phase
all of the above
The _____ of a signal is the time needed to complete one cycle.
amplitude
frequency
phase
period
The simplest analogue signal is the:
sinusoidal
analogue
digital
periodic
