Category: Wireless & Mobile Communications Objective Questions

250+ TOP MCQs on Network Protocols and Answers

Wireless & Mobile Communications Multiple Choice Questions on “Network Protocols”.

1. Several protocols for upper layers in bluetooth use _________
a) UDP
b) HSP
c) ITC
d) L2CAP
Answer: d
Clarification: L2CAP is Logical Link, Control Adaptation Protocol Layer. The logical unit link control adaptation protocol is equivalent to logical link control sub layer of LAN. The ACL link uses L2CAP for data exchange. The various function of L2CAP is segmentation and reassembly, multiplexing and quality of service.

2. Protocols are set of rules to govern _________
a) Communication
b) Standard
c) Metropolitan communication
d) Bandwidth
Answer: a
Clarification: A protocol is a set of rules that governs the communications between computers on a network. These rules include guidelines that regulate the characteristics of a network including access method, allowed physical topologies, types of cabling, and speed of data transfer.

3. An internet is a __________
a) Collection of WANS
b) Network of networks
c) Collection of LANS
d) Collection of identical LANS and WANS
Answer: b
Clarification: Internet is a massive network of networks, a networking infrastructure. It connects millions of computers together globally, forming a network in which any computer can communicate with any other computer as long as they are both connected to the Internet.

4. Checksum is used in Internet by several protocols although not at the _________
a) Session layer
b) Transport layer
c) Network layer
d) Data link layer
Answer: d
Clarification: The checksum is used in the Internet by several protocols although not at the data link layer. Like linear and cyclic codes, the checksum is based on the concept of redundancy. Several protocols still use the checksum for error detection.

5. In version field of IPv4 header, when machine is using some other version of IPv4 then datagram is __________
a) Discarded
b) Accepted
c) Interpreted
d) Interpreted incorrectly
Answer: a
Clarification: A 4 bit field defines the version of IPv4 protocol. This field tells the software running in the processing machine that the datagram has the format of version 4. If the machine is using some other version of IPv4, the datagram is discarded rather than interpreted incorrectly.

6. Network layer at source is responsible for creating a packet from data coming from another ________
a) Station
b) Link
c) Node
d) Protocol
Answer: d
Clarification: ‘The network layer at the source is responsible for creating a packet from the data coming from another’ protocol (such as a transport layer protocol or a routing protocol). The network layer is responsible for checking its routing table to find the routing information.

7. Header of datagram in IPv4 has _________
a) 0 to 20 bytes
b) 20 to 40 bytes
c) 20 to 60 bytes
d) 20 to 80 bytes
Answer: c
Clarification: IP header length is a minimum of 20 bytes and a maximum of 60 bytes. The minimum value for this field is 5, which is a length of 5×32 = 160 bits = 20 bytes. Being a 4-bit value, the maximum length is 15 words (15×32 bits) or 480 bits = 60 bytes.

8. In IPv4 layer, datagram is of ________
a) Fixed length
b) Variable length
c) Global length
d) Zero length
Answer: b
Clarification: ‘IPv4 is a connectionless protocol used for packet switched networks. It operates on best effort delivery model, in which neither delivery is guaranteed, nor proper sequencing or avoidance of duplicate delivery is assured. The size of the datagram header can be of variable length from 20 bytes to 60 bytes.’

9. In IPv4, service type of service in header field, first 3 bits are called ______
a) Type of service
b) Code bits
c) Sync bits
d) Precedence bits
Answer: d
Clarification: The 8-bit ToS (type of service) in IPv4 uses 3 bits for IP Precedence, 4 bits for ToS with the last bit not being used. The 4-bit ToS field, although defined, has never been used.

10. Which is a link layer protocol?
a) ARP
b) TCP
c) UDP
d) HTTP
Answer: b
Clarification: ‘In computer networking, the link layer is the lowest layer in the Internet Protocol Suite. It is commonly known as TCP/IP, the networking architecture of the Internet. It is described in RFC 1122 and RFC 1123.’

11. Which protocol is commonly used to retrieve email from a mail server?
a) FTP
b) IMAP
c) HTML
d) TELNET
Answer: b
Clarification: ‘The Internet Message Access Protocol (IMAP) is a mail protocol used for accessing email on a remote web server from a local client. IMAP is the most commonly used Internet mail protocols for retrieving emails. It is supported by all modern email clients and web servers.’

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250+ TOP MCQs on Frequency Reuse and Answers

Wireless & Mobile Communications Multiple Choice Questions on “Frequency Reuse”.

1. Cellular concept replaces many low power transmitters to a single high power transmitter.
a) True
b) False

Answer: b
Clarification: Cellular concept is a system level idea that replaces a single high power transmitter to many low power transmitters. High power transmitters lead to large cell, and thus it was impossible to use the same frequencies throughout the systems. But, it is possible with low power transmitter.

2. Why neighbouring stations are assigned different group of channels in cellular system?
a) To minimize interference
b) To minimize area
c) To maximize throughput
d) To maximize capacity of each cell

Answer: a
Clarification: Neighbouring base stations are assigned different group of channels. It minimizes the interference between base stations and the users under their control.

3. What is a cell in cellular system?
a) A group of cells
b) A group of subscribers
c) A small geographical area
d) A large group of mobile systems

Answer: c
Clarification: Cell is a small geographic area in a cellular system. Each cellular base station within a cell is allocated a group of radio channels that could be used in another cell.

4. What is frequency reuse?
a) Process of selecting and allocating channels
b) Process of selection of mobile users
c) Process of selecting frequency of mobile equipment
d) Process of selection of number of cells

Answer: a
Clarification: Frequency reuse is the process of using the same radio frequencies on radio transmitter sites within a geographic area. They are separated by sufficient distance to cause minimal interference with each other.

5. Which of the following is a universally adopted shape of cell?
a) Square
b) Circle
c) Triangle
d) Hexagon

Answer: d
Clarification: Hexagonal cell shape is a simplistic model of radio coverage for each base station. It has been universally adopted since the hexagon permits easy and manageable analysis of a cellular system.

6. Actual radio coverage of a cell is called __________
a) Fingerprint
b) Footprint
c) Imprint
d) Matrix

Answer: b
Clarification: Actual radio coverage of a cell is known as the footprint. It is determined from field measurements or propagation prediction models. Although the real footprint is amorphous in nature, a regular cell shape is needed for systematic system design.

7. Why the shape of cell is not circle?
a) Omni directionality
b) Small area
c) Overlapping regions or gaps are left
d) Complex design

Answer: c
Clarification: Circle is the first natural choice to represent the coverage area of a base station. But while adopting this shape, adjacent cells cannot be overlaid upon a map without leaving gaps or creating overlapping regions.

8. What is the main reason to adopt hexagon shape in comparison to square and triangle?
a) Largest area
b) Simple design
c) Small area
d) Single directional

Answer: a
Clarification: For a given distance between the center of a polygon and its farthest perimeter points, the hexagon has the largest area. Thus, by using the hexagon geometry, the fewest number of cells can cover a geographic region.

9. Which type of antenna is used for center excited cells?
a) Dipole antenna
b) Grid antenna
c) Sectored antenna
d) Omnidirectional antenna

Answer: d
Clarification: For center excited cells, base station transmitters are used at the center of cell. To cover the whole cell, omnidirectional antenna is the best choice for base station transmitters.

10. Which type of antenna is used for edge excited cells?
a) Omnidirectional antenna
b) Grid antenna
c) Sectored directional antenna
d) Dipole antenna

Answer: c
Clarification: For edge excited cell, mostly base station transmitters are placed on three of the six cell vertices. To cover the assigned portion of a cell, sectored directional antenna is the best choice.

11. For a cellular system, if there are N cells and each cell is allocated k channel. What is the total number of available radio channels, S?
a) S=k*N
b) S=k/N
c) S=N/k
d) S=kN

Answer: a
Clarification: If there is a cellular system with total of S duplex channels. Each cell is allocated a group of k channels and there are total N cells in the system, S channels are divide among N cells into unique and disjoint channel groups. Therefore, total number of radio channel is the product of total number of cells in the system (N) and number of channel allocated to each cell (k).

12. What is a cluster in a cellular system?
a) Group of frequencies
b) Group of cells
c) Group of subscribers
d) Group of mobile systems

Answer: b
Clarification: Cluster is group of N cells. These cells use the complete set of frequency available for the cellular system at that location.

13. What is a frequency reuse factor for N number of cells in a system?
a) N
b) N2
c) 2*N
d) 1/N

Answer: d
Clarification: The frequency reuse factor is defined as 1 over the number of cells in the cluster of the system (N). It is given by 1/N since each cell within a cluster is only assigned 1/N of the total available channels in the system.

14. Capacity of a cellular system is directly proportional to __________
a) Number of cells
b) Number of times a cluster is replicated
c) Number of Base stations
d) Number of users

Answer: b
Clarification: The capacity of a cellular system is directly proportional to the number of times a cluster is replicated in a fixed area. If the cluster size N is reduced while the cell size is kept constant, more clusters are required to cover a given area, and hence more capacity is achieved.

15. A spectrum of 30 MHz is allocated to a cellular system which uses two 25 KHz simplex channels to provide full duplex voice channels. What is the number of channels available per cell for 4 cell reuse factor?
a) 150 channels
b) 600 channels
c) 50 channels
d) 85 channels

Answer: a
Clarification: Total bandwidth is 30 MHz. And the channel bandwidth is 50 KHz/duplex channel (25KHz*2). Therefore, total available channels are 600 channels (30,000/50). For 4 cell reuse factor, total number of channels available per cell will be 150 channels (600/4).

250+ TOP MCQs on Parameters of Mobile Multipath Channels and Answers

Wireless & Mobile Communications Problems on “Parameters of Mobile Multipath Channels”.

1. Power delay profile is represented as plots of __________ with respect to fixed time delay reference.
a) Relative received power
b) Frequency
c) Transmitted power
d) Relative power
Answer: a
Clarification: Power delay profiles are generally represented as plots of relative received power as a function of excess delay with respect to a fixed time delay reference. They are calculated by averaging instantaneous power delay profile measurements over a local area.

2. Which of the following is not a multipath channel parameter that can be determined from power delay profile?
a) Mean excess delay
b) RMS delay spread
c) Excess delay spread
d) Doppler spread
Answer: d
Clarification: The mean excess delay, excess delay spread and rms delay spread are some multipath channel parameters. They can be determined from a power delay profile. Doppler spread is a measure of spectral broadening caused by time rate of change of mobile radio channel.

3. The time dispersive properties of wideband multipath channel are quantified by ______ and _______
a) Mean excess delay, rms delay spread
b) Doppler spread, rms delay spread
c) Doppler spread, coherence time
d) Mean excess delay, Doppler spread
Answer: a
Clarification: The time dispersive properties of wide band multipath channels are most commonly quantified by their mean excess delay and rms delay spread. Coherence time characterizes the time varying nature of frequency dispersiveness of mobile radio channel in time domain.

4. _______ is the square root of the second central moment of the power delay profile.
a) Mean excess delay
b) Rms delay spread
c) Excess delay spread
d) Coherence time
Answer: b
Clarification: The rms delay spread is the square root of the second central moment of the power delay profile. Many measurements are made at many local areas in order to determine a statistical range of multipath channel parameters for a mobile communication system over a large scale area.

5. Which of the following is the first moment of the power delay profile?
a) Rms delay spread
b) Excess delay spread
c) Mean excess delay
d) Doppler spread
Answer: c
Clarification: Mean excess delay is the first moment of the power delay profile. It is defined from a single power delay profile which is temporal or spatial average of consecutive impulse response measurements collected and averaged over a local area.

6. What is the order of typical values of rms delay spread in outdoor mobile radio channels?
a) Microseconds
b) Nanoseconds
c) Seconds
d) Minutes
Answer: a
Clarification: Typical values of rms delay spread are on the order of microseconds in outdoor mobile radio channels. For indoor mobile radio channels, they are of the order of nanoseconds.

7. Power delay profile and magnitude frequency response of a mobile radio channel are related through _______
a) Laplace Transform
b) Fourier Transform
c) S Transform
d) Wavelet Transform
Answer: b
Clarification: Power delay profile and magnitude frequency response of a mobile radio channel are related through the Fourier transform. Therefore, it is possible to obtain an equivalent description of the channel in the frequency domain using its frequency response characteristics.

8. ______ and coherence bandwidth are inversely proportional to one another.
a) Rms delay spread
b) Mean excess delay
c) Excess delay spread
d) Doppler spread
Answer: a
Clarification: The rms delay spread and coherence bandwidth are inversely proportional to one another. However, their exact relationship is a function of the exact multipath structure.

9. Coherence bandwidth is a statistical measure of range of frequencies over which channel is considered _______
a) Time dispersive
b) Frequency selective
c) Time variant
d) Flat
Answer: d
Clarification: Coherence bandwidth is a statistical measure of range of frequencies over which channel is considered flat. A flat channel is a channel which passes all spectral components with approximately equal gain and linear phase.

10. Which of the following describes time varying nature of the channel in a small scale region?
a) Delay spread and coherence time
b) Coherence bandwidth and delay spread
c) Doppler spread and coherence time
d) Delay spread and doppler spread
Answer: c
Clarification: Delay spread and coherence bandwidth describes the time dispersive nature of the channel in a local area. They do not give information about the time varying nature of the channel caused by either relative motion between the mobile and base station, or by movement of objects in the channel.

11. Doppler spread is a range of frequencies over which received Doppler spread is _______
a) Zero
b) Non zero
c) Infinite
d) One
Answer: b
Clarification: Doppler spread is a range of frequencies over which received Doppler spectrum is essentially non-zero. It is a measure of spectral broadening caused by time rate of change of mobile radio channel.

12. _______ is a statistical measure of time duration over which channel impulse response is invariant.
a) Coherence time
b) Doppler spread
c) Mean excess delay
d) Rms delay spread
Answer: a
Clarification: Coherence time is actually a statistical measure of the time duration over which the channel impulse response is essentially invariant. It quantifies the similarity of the channel response at varying times.

of Wireless & Mobile Communications Problems, .

250+ TOP MCQs on Equalization Techniques and Answers

Wireless & Mobile Communications Multiple Choice Questions on “Equalization Techniques”.

1. Equalization techniques can be categorised into _______ and ______ techniques.
a) Linear, non linear
b) Active, passive
c) Direct, indirect
d) Slow, fast

Answer: a
Clarification: Equalization techniques can be classified into linear and non linear techniques. These categories are determined from how the output of an adaptive equalizer is used for subsequent control of the equalizer.

2. Equalization is linear if an analog signal is fed back to change the subsequent outputs of the equalizer.
a) True
b) False

Answer: b
Clarification: If the analog signal is not used in the feedback path to adapt the equalizer, the equalization is linear. On the other hand, if it is fed back to change the subsequent outputs of the equalizer, the equalization is non-linear.

3. In the context of equalizers, LTE stands for ________
a) Long transversal equalizer
b) Least time-varying equalizer
c) Linear transversal equalizer
d) Linear time-varying equalizer

Answer: c
Clarification: The most common equalizer structure used for equalization is linear transveral equalizer (LTE). It is made up of tapped delay lines, with the tappings speed a symbol period apart.

4. Which of the following is not a characteristic of FIR filter?
a) Many zeroes
b) Poles only at z=0
c) Transfer function is a polynomial of z-1
d) Many poles

Answer: d
Clarification: Finite impulse response filter (FIR) has many zeroes but poles only at z=0. The transfer function of the filter is a polynomial of z-1. It is also referred to as transversal filter.

5. Which of the following is not an advantage of lattice equalizer?
a) Simple structure
b) Numerical stability
c) Faster convergence
d) Dynamic assignment

Answer: a
Clarification: The structure of lattice equalizer is more complicated than a linear transversal equalizer. But, numerical stability and faster convergence are two advantage of laatic equalizer. Also, its unique structure allows dynamic assignment of the most effective length of lattice equalizer.

6. Non-linear equalizers are used in applications where channel distortion is not severe.
a) True
b) False

Answer: b
Clarification: Non-linear equalizers are used in applications where the channel distortion is too severe for a linear equalizer to handle. They are most commonly used in practical wireless communication.

7. Which of the following is not a non-linear equalization technique?
a) Decision feedback equalization
b) Maximum likelihood symbol detection
c) Minimum square error detection
d) Maximum likelihood sequence detection

Answer: c
Clarification: Decision feedback equalization, maximum likelihood symbol detection and maximum likelihood sequence detection offers non-linear equalization. They offer improvements over linear equalization techniques and are used in most 2G and 3G systems.

8. For a distorted channel, LTE performance is superior to DFE.
a) True
b) False

Answer: b
Clarification: LTE is well behaved when the channel spectrum is comparatively flat. But if the channel is severely distorted or exhibits null in the spectrum, the performance of LTE deteriorates and MSE of DFE is better than LTE.

9. Which of the following does not hold true for MLSE?
a) Minimizes probability of sequence error
b) Require knowledge of channel characteristics
c) Requires the statistical distribution of noise
d) Operates on continuous time signal

Answer: d
Clarification: Matched filter operates on the continuous time signal, whereas maximum likelihood sequence estimation (MLSE) equalizer and channel estimator rely on discretized samples. MLSE is optimal in the sense that it minimizes the probability of sequence error.

10. MLSE decodes each received signal by itself.
a) True
b) False

Answer: b
Clarification: Rather than decoding each received signal by itself, MLSE tests all possible data sequences by using a channel impulse response simulator within the algorithm. It chooses the data sequence with maximum probability as the output.

250+ TOP MCQs on Packet Radio and Answers

Wireless & Mobile Communications Multiple Choice Questions on “Packet Radio”.

1. In ___________ technique, many subscribers attempt to access a single channel in an uncoordinated manner.
a) Packet radio
b) Multiple access
c) Modulation
d) Spread spectrum

Answer: a
Clarification: In packet radio (PR) access techniques, many subscribers attempt to access a single channel in an uncoordinated (or minimally coordinated) manner. Transmission is done by using bursts of data.

2. Packet radio uses _________ and __________ signals for perfect feedback.
a) Forward, reverse
b) ACK, NACK
c) Active, passive
d) Linear, non linear

Answer: b
Clarification: Packet radio uses ACK and NACK signals for perfect feedback. The ACK signal indicates an acknowledgment of a received burst and NACK indicates that the previous burst was not received correctly by base station.

3. Packet radio has high spectral efficiency.
a) True
b) False

Answer: b
Clarification: Packet radio multiple access is very easy to implement, but has low spectral efficiency and may induce delays. The subscriber uses a contention technique to transmit on a common channel.

4. ___________ is defined as average number of messages successfully transmitted per unit time in packet radio multiple access technique.
a) Average delay
b) Figure of merit
c) Throughput
d) Efficiency

Answer: c
Clarification: The performance of contention technique can be evaluated by the throughput (T), which is defined as the average number of messages successfully transmitted per unit time, and the average delay experienced by a typical message burst.

5. What is the time period during which the packets are susceptible to collisions with transmissions from other users?
a) Delay time
b) Latency period
c) Average delay time
d) Vulnerable period

Answer: d
Clarification: Vulnerable period is the time period during which the packets are susceptible to collisions with transmissions from other users. It is used in order to determine the throughput.

6. For a PR multiple access technique, packet transmissions occur with __________ distribution.
a) Poisson
b) Gaussian
c) Pearson
d) Rayleigh

Answer: a
Clarification: For a PR multiple access technique, packet transmissions occur with Poisson distribution. To study packet radio protocols, it is assumed that all packets sent by all users have a constant packet length and fixed channel rate.

7. If λ is mean arrival rate and τ is the packet duration, then traffic occupancy of a packet radio network is equal to _________
a) λτ
b) λ/τ
c) λ-τ
d) λτ2

Answer: a
Clarification: If λ is mean arrival rate and τ is the packet duration, then traffic occupancy or throughput of a packet radio network is equal to λτ. The unit of R is in Erlangs.

8. Pure ALOHA is __________
a) Modulation technique
b) Multiple access technique
c) Random access technique
d) Spread spectrum technique

Answer: c
Clarification: The pure ALOHA protocol is a random access protocol used for data transfer. A user accesses a channel as soon as a message is ready to be transmitted.

9. For pure ALOHA protocol, the vulnerable period is ___________ the packet duration.
a) Double
b) Equal
c) Ten times
d) Not equal

Answer: a
Clarification: For the pure ALOHA protocol, the vulnerable period is double the packet duration. After a transmission, the user waits for an acknowledgement on either the same channel or a separate feedback channel.

10. The vulnerable period of slotted ALOHA is _________ packet duration.
a) Two
b) Ten
c) One
d) Three

Answer: c
Clarification: The vulnerable period of slotted ALOHA is one packet duration. Since, partial collisions are prevented through synchronization.

11. In slotted ALOHA, time is divided into different length of time slots.
a) True
b) False

Answer: b
Clarification: In slotted ALOHA, time is divided into equal time slots of length greater than the packet duration. The subscribers each have synchronized clocks and transmit a message only at the beginning of a new time slot.

12. CSMA stands for _________
a) Carrier sense multiple access
b) Code sense multiple access
c) Carrier sense modulation access
d) Carry sense multiple access

Answer: a
Clarification: CSMA stands for carrier sense multiple access. CSMA protocol is based on the fact that each terminal on the network is able to monitor the status of the channel before transmitting information.

13. __________ is the time required for a terminal to sense whether or not the channel is idle.
a) Propagation delay
b) Average delay
c) Detection delay
d) Time delay

Answer: c
Clarification: In CSMA protocols, detection delay and propagation delay are two important parameters. Detection delay is a function of the receiver hardware and is the time required for a terminal to sense whether or not the channel is idle.

14. Which of the following is based on time division multiplexing?
a) Slotted ALOHA
b) Pure ALOHA
c) CSMA
d) Reservation ALOHA

Answer: d
Clarification: Reservation ALOHA is a packet access scheme based on time division multiplexing. In this protocol, certain packet slots are assigned with priority, and it is possible for users to reserve slots for the transmission of packets.

15. Discrete packet time technique, PRMA stands for _________
a) Packet reservation multiple access
b) Photo reflector multiple access
c) Proton reflector modulating access
d) Packet reflection multiple access

Answer: a
Clarification: PRMA stands for Packet Reservation Multiple Access. PRMA uses a discrete packet time technique similar to reservation ALOHA and combines the cyclical frame structure of TDMA in a manner that allows each TDMA time slot to carry either voice or data, where voice is the priority.

250+ TOP MCQs on TCP/IP Protocol and Answers Download

Wireless & Mobile Communications Multiple Choice Questions on “TCP/IP Protocol”.

1. What layer in the TCP/IP stack is equivalent to the Transport layer of the OSI model?
a) Application
b) Host to host
c) Internet
d) Network Access

Answer: b
Clarification: The four layers of the TCP/IP stack (also called the DoD model) are Application/Process, Host-to-Host, Internet, and Network Access. The Host-to-Host layer is equivalent to the Transport layer of the OSI model.

2. You want to implement a mechanism that automates the IP configuration, including IP address, subnet mask, default gateway, and DNS information. Which protocol will you use to accomplish this?
a) SMTP
b) SNMP
c) DHCP
d) ARP

Answer: c
Clarification: Dynamic Host Configuration Protocol (DHCP) is used to provide IP information to hosts on your network. DHCP can provide a lot of information, but the most common is the IP address, subnet mask, default gateway, and DNS information.

3. The DoD model (also called the TCP/IP stack) has four layers. Which layer of the DoD model is equivalent to the Network layer of the OSI model?
a) Application
b) Host to Host
c) Internet
d) Network Access

Answer: c
Clarification: The four layers of the DoD model are Application/Process, Host-to-Host, Internet, and Network Access. The Internet layer is equivalent to the Network layer of the OSI model.

4. Which of the following protocols uses both TCP and UDP?
a) FTP
b) SMTP
c) Telnet
d) DNS

Answer: d
Clarification: DNS and some other services work on both TCP and the UDP protocols. DNS uses TCP for zone exchanges between servers and UDP when a client is trying to resolve a hostname to an IP address.

5. Length of Port address in TCP/IP is _________
a) 4bit long
b) 16bit long
c) 32bit long
d) 8 bit long

Answer: b
Clarification: TCP and UDP port numbers are 16 bits in length. So, valid port numbers can theoretically take on values from 0 to 65,535. These values are divided into ranges for different purposes, with certain ports reserved for particular uses.

6. TCP/IP layer is equivalent to combined Session, Presentation and _________
a) Network layer
b) Application layer
c) Transport layer
d) Physical layer

Answer: b
Clarification: TCP/IP network model is a hierarchical protocol made up of interactive modules, each of which provides a specific functionality; however, the modules are not necessarily interdependent. It is equivalent to combined session, presentation and application layer.

7. How many levels of addressing is provided in TCP/IP protocol?
a) One
b) Two
c) Three
d) Four

Answer: d
Clarification: Four levels of addresses are used in the internet employing the TCP/IP protocols. They are physical (link) addresses, logical (IP) addresses, port addresses, and specific addresses.

8. Virtual terminal protocol is an example of _________
a) Network layer
b) Application layer
c) Transport layer
d) Physical layer

Answer: b
Clarification: In open systems, a virtual terminal (VT) is an application service. It allows host terminals on a multi-user network to interact with other hosts regardless of terminal type and characteristics.

9. TCP/IP is related to __________
a) ARPANET
b) OSI
c) DECNET
d) ALOHA

Answer: a
Clarification: In 1983, TCP/IP protocols replaced NCP (Network Control Program) as the ARPANET’s principal protocol. And ARPANET then became one component of the early Internet. The starting point for host-to-host communication on the ARPANET in 1969 was the 1822 protocol, which defined the transmission of messages to an IMP.

10. A device operating at network layer is called __________
a) Router
b) Equalizer
c) Bridge
d) Repeater

Answer: a
Clarification: A router is a networking device that forwards data packets between computer networks. Routers perform the traffic directing functions on the Internet. It supports different network layer transmission standards. Each network interface is used to enable data packets to be forwarded from one transmission system to another.

11. A device operating at physical layer is called __________
a) Router
b) Equalizer
c) Bridge
d) Repeater

Answer: d
Clarification: A repeater connects two segments of your network cable. It retimes and regenerates the signals to proper amplitudes and sends them to the other segments. Repeaters work only at the physical layer of the OSI network model.