1. The physical layer is concerned with ___________
a) bit-by-bit delivery
p) process to process delivery
c) application to application delivery
d) port to port delivery
Answer: a
Explanation: Physical layer deals with bit to bit delivery in networking. The data unit in the physical layer is bits. Process to process delivery or the port to port delivery is dealt in the transport layer. The various transmission mediums aid the physical layer in performing its functions.

2. Which transmission media provides the highest transmission speed in a network?
a) coaxial cable
b) twisted pair cable
c) optical fiber
d) electrical cable
Answer: c
Explanation: Fiber optics is considered to have the highest transmission speed among the all mentioned above. The fiber optics transmission runs at 1000Mb/s. It is called as 1000Base-Lx whereas IEEE standard for it is 802.3z. It is popularly used for modern day network connections due to its high transmission rate.

3. Bits can be sent over guided and unguided media as analog signal by ___________
a) digital modulation
b) amplitude modulation
c) frequency modulation
d) phase modulation
Answer: a
Explanation: In analog modulation, digital low frequency baseband signal (digital bit stream) is transmitted over a higher frequency. Whereas in digital modulation the only difference is that the base band signal is of discrete amplitude level. The bits are represented by only two frequency levels, one for high and one for low.

4. The portion of physical layer that interfaces with the media access control sublayer is called ___________
a) physical signalling sublayer
b) physical data sublayer
c) physical address sublayer
d) physical transport sublayer
Answer: a
Explanation: The portion of physical layer that interfaces with the medium access control sublayer is Physical Signaling Sublayer. The main function of this layer is character encoding, reception, decoding and performs optional isolation functions. It handles which media connection the signal should be forwarded to physically.

5. The physical layer provides __________
a) mechanical specifications of electrical connectors and cables
b) electrical specification of transmission line signal level
c) specification for IR over optical fiber
d) all of the mentioned
Answer: d
Explanation: Anything dealing with a network cable or the standards in use – including pins, connectors and the electric current used is dealt in the physical layer (Layer 1). Physical layer deals with bit to bit delivery of the data aided by the various transmission mediums.

6. In asynchronous serial communication the physical layer provides ___________
a) start and stop signalling
b) flow control
c) both start & stop signalling and flow control
d) only start signalling
Answer: c
Explanation: In asynchronous serial communication, the communication is not synchronized by clock signal. Instead of a start and stop signaling and flow control method is followed. Unlike asynchronous serial communication, in synchronous serial communication a clock signal is used for communication, so the start and stop method is not really required.

7. The physical layer is responsible for __________
a) line coding
b) channel coding
c) modulation
d) all of the mentioned
Answer: d
Explanation: The physical layer is responsible for line coding, channel coding and modulation that is needed for the transmission of the information. The physical configuration including pins, connectors and the electric current used is dealt in the physical layer based on the requirement of the network application.

8. The physical layer translates logical communication requests from the ______ into hardware specific operations.
a) data link layer
b) network layer
c) trasnport layer
d) application layer
Answer: a
Explanation: Physical layer accepts data or information from the data link layer and converts it into hardware specific operations so as to transfer the message through physical cables. Some examples of the cables used are optical fiber cables, twisted pair cables and co-axial cables.

9. A single channel is shared by multiple signals by ____________
a) analog modulation
b) digital modulation
c) multiplexing
d) phase modulation
Answer: c
Explanation: In communication and computer networks, the main goal is to share a scarce resource. This is done by multiplexing, where multiple analog or digital signals are combined into one signal over a shared medium. The multiple kinds of signals are designated by the transport layer which is the layer present on a higher level than the physical layer.

10. Wireless transmission of signals can be done via ___________
a) radio waves
b) microwaves
c) infrared
d) all of the mentioned
Answer: d
Explanation: Wireless transmission is carried out by radio waves, microwaves and IR waves. These waves range from 3 Khz to above 300 Ghz and are more suitable for wireless transmission. Radio waves can penetrate through walls and are used in radio communications, microwaves and infrared (IR) waves cannot penetrate through walls and are used for satellite communications and device communications respectively.

11. The data link layer takes the packets from _________ and encapsulates them into frames for transmission.
a) network layer
b) physical layer
c) transport layer
d) application layer
Answer: a
Explanation: In computer networks, the data from application layer is sent to transport layer and is converted to segments. These segments are then transferred to the network layer and these are called packets. These packets are then sent to data link layer where they are encapsulated into frames. These frames are then transferred to physical layer where the frames are converted to bits. Error control and flow control data is inserted in the frames at the data link layer.

12. Which of the following tasks is not done by data link layer?
a) framing
b) error control
c) flow control
d) channel coding
Answer: d
Explanation: Channel coding is the function of physical layer. Data link layer mainly deals with framing, error control and flow control. Data link layer is the layer where the packets are encapsulated into frames.

13. Which sublayer of the data link layer performs data link functions that depend upon the type of medium?
a) logical link control sublayer
b) media access control sublayer
c) network interface control sublayer
d) error control sublayer
Answer: b
Explanation: Media access control (MAC) deals with transmission of data packets to and from the network-interface card, and also to and from another remotely shared channel. The MAC sublayer also prevents collision using protocols like CSMA/CD.

14. Header of a frame generally contains ______________
a) synchronization bytes
b) addresses
c) frame identifier
d) all of the mentioned
Answer: d
Explanation: In a frame, the header is a part of the data that contains all the required information about the transmission of the file. It contains information like synchronization bytes, addresses, frame identifier etc. It also contains error control information for reducing the errors in the transmitted frames.

15. Automatic repeat request error management mechanism is provided by ________
a) logical link control sublayer
b) media access control sublayer
c) network interface control sublayer
d) application access control sublayer
Answer: a
Explanation: The logical link control is a sublayer of data link layer whose main function is to manage traffic, flow and error control. The automatic repeat request error management mechanism is provided by the LLC when an error is found in the received frame at the receiver’s end to inform the sender to re-send the frame.

16. When 2 or more bits in a data unit has been changed during the transmission, the error is called ____________
a) random error
b) burst error
c) inverted error
d) double error
Answer: b
Explanation: When a single bit error occurs in a data, it is called single bit error. When more than a single bit of data is corrupted or has error, it is called burst error. If a single bit error occurs, the bit can be simply repaired by inverting it, but in case of a burst error, the sender has to send the frame again.

17. CRC stands for __________
a) cyclic redundancy check
b) code repeat check
c) code redundancy check
d) cyclic repeat check
Answer: a
Explanation: Cyclic redundancy check is a code that is added to a data which helps us to identify any error that occurred during the transmission of the data. CRC is only able to detect errors, not correct them. CRC is inserted in the frame trailer.

18. Which of the following is a data link protocol?
a) ethernet
b) point to point protocol
c) hdlc
d) all of the mentioned
Answer: d
Explanation: There are many data link layer protocols. Some of them are SDLC (synchronous data link protocol), HDLC (High level data link control), SLIP (serial line interface protocol), PPP (Point to point protocol) etc. These protocols are used to provide the logical link control function of the Data Link Layer.

19. Which of the following is the multiple access protocol for channel access control?
a) CSMA/CD
b) CSMA/CA
c) Both CSMA/CD & CSMA/CA
d) HDLC
Answer: c
Explanation: In CSMA/CD, it deals with detection of collision after collision has occurred, whereas CSMA/CA deals with preventing collision. CSMA/CD is abbreviation for Carrier Sensing Multiple Access/Collision detection. CSMA/CA is abbreviation for Carrier Sensing Multiple Access/Collision Avoidance. These protocols are used for efficient multiple channel access.

20. The technique of temporarily delaying outgoing acknowledgements so that they can be hooked onto the next outgoing data frame is called ____________
a) piggybacking
b) cyclic redundancy check
c) fletcher’s checksum
d) parity check
Answer: a
Explanation: Piggybacking is a technique in which the acknowledgment is temporarily delayed so as to be hooked with the next outgoing data frame. It saves a lot of channel bandwidth as in non-piggybacking system, some bandwidth is reserved for acknowledgement.

21. Physical or logical arrangement of network is __________
a) Topology
b) Routing
c) Networking
d) Control
Answer: a
Explanation: Topology in networks is the structure or pattern in which each and every node in the network is connected. There are many topologies in networking like bus, tree, ring, star, mesh, and hybrid topology. There is no particular best topology and a suitable topology can be chosen based on the kind of application of the network .

22. Which network topology requires a central controller or hub?
a) Star
b) Mesh
c) Ring
d) Bus
Answer: a
Explanation: In star topology, no computer is connected to another computer directly but all the computers are connected to a central hub. Every message sent from a source computer goes through the hub and the hub then forwards the message only to the intended destination computer.

23. _______ topology requires a multipoint connection.
a) Star
b) Mesh
c) Ring
d) Bus
Answer: d
Explanation: In bus topology, there is a single cable to which all the network nodes are connected. So whenever a node tries to send a message or data to other nodes, this data passes through all other nodes in the network through the cable. It is really simple to install but it’s not secure enough to be used in most of the computer network applications.

24. Data communication system spanning states, countries, or the whole world is ________
a) LAN
b) WAN
c) MAN
d) PAN
Answer: b
Explanation: WAN is the abbreviation for Wide Area Network. This network extends over a large geographical area. WANs are used to connect cities, states or even countries. A wireless connection is required to build a WAN. The best example of WAN is the Internet.

25. Data communication system within a building or campus is________
a) LAN
b) WAN
c) MAN
d) PAN
Answer: a
Explanation: LAN is an abbreviation for Local Area Network. This network interconnects computers in a small area such as schools, offices, residence etc. It is the most versatile kind of data communication system where most of the computer network concepts can be visibly used.

26. WAN stands for __________
a) World area network
b) Wide area network
c) Web area network
d) Web access network
Answer: b
Explanation: WAN is the abbreviation for Wide Area Network. This network extends over a large geographical area. These are used to connect cities, states or even countries. They can be connected through leased lines or satellites.

27. In TDM, slots are further divided into __________
a) Seconds
b) Frames
c) Packets
d) Bits
Answer: b
Explanation: TDM is the abbreviation for Time division multiplexing. It is technique for combining several low rate channels to a single high rate channel. For a certain time slot, the several channels could use the maximum bandwidth. Each channel is inactive for a period of time too. Some other multiplexing techniques are Frequency division multiplexing and Phase division multiplexing.

28. _____ is the multiplexing technique that shifts each signal to a different carrier frequency.
a) FDM
b) TDM
c) Both FDM & TDM
d) PDM
Answer: a
Explanation: FDM is an abbreviation for Frequency Division Multiplexing. This technique is used when the bandwidth of the channel is greater than the combined bandwidth of all the signals which are to be transmitted. The channel is active at all times unless a collision occurs with another channel trying to use the same frequency. Some other multiplexing techniques are Time division multiplexing and Phase division multiplexing.

29. The sharing of a medium and its link by two or more devices is called _________
a) Fully duplexing
b) Multiplexing
c) Micropleixng
d) Duplexing
Answer: b
Explanation: Multiplexing is a method using which one can send multiples signals through a shared medium at the same time. This helps in using less resources and thus saving the cost of sending messages.

30. Multiplexing is used in _______
a) Packet switching
b) Circuit switching
c) Data switching
d) Packet & Circuit switching
Answer: b
Explanation: Circuit switching is a switching method by which one can obtain a physical path between end points. Circuit switching method is also called a connection oriented network. Two nodes must be physically and logically connected to each other to create a circuit switching network.

31. Which multiplexing technique used to transmit digital signals?
a) FDM
b) TDM
c) WDM
d) FDM & WDM
Answer: b
Explanation: TDM abbreviation for Time Division Multiplexing is a method used for digital signals. Whereas FDM and WDM abbreviation for Frequency Division Multiplexing, and Wavelength Division Multiplexing, are used for analog signals. TDM is used in applications like ISDN (Integrated Services Digital Network) and PSTN (Public Switched Telephone Network).

32. If there are n signal sources of same data rate, then the TDM link has _______ slots.
a) n
b) n/2
c) n*2
d) 2n
Answer: a
Explanation: In TDM, the total unit of time is divided equally among all the signal sources and each and every source has access to the complete channel bandwidth during its allotted time slot. When the time slot of the source is not active, it remains idle and waits for its slot to begin.

33. If link transmits 4000frames per second, and each slot has 8 bits, the transmission rate of circuit this TDM is _________
a) 32kbps
b) 500bps
c) 500kbps
d) 32bps
Answer: a
Explanation: Transmission rate= frame rate * number of bits in a slot.
Given: Frame rate = 4000/sec and number of bits in slot = 8
Thus, Transmission rate = (4000 * 8) bps
= 32000bps
= 32kbps

34. The state when dedicated signals are idle are called __________
a) Death period
b) Poison period
c) Silent period
d) Stop period
Answer: c
Explanation: There are instances when connection between two endpoints has been established, but no communication or transfer of messages occurs. This period of time is called silent period. The silent period ends when either of the two endpoints starts the communication.

35. Multiplexing provides _________
a) Efficiency
b) Privacy
c) Anti jamming
d) Both Efficiency & Privacy
Answer: d
Explanation: Multiplexing helps us to transfer our messages over a shared channel. This brings up the issue of privacy and efficiency. Fortunately, Multiplexing has high efficiency and high privacy when implemented because in the implementation, the transport layer of the OSI network model handles the function of multiplexing through interfaces called ports which provide the required efficiency and privacy.

36. In TDM, the transmission rate of a multiplexed path is always _______ the sum of the transmission rates of the signal sources.
a) Greater than
b) Lesser than
c) Equal to
d) Equal to or greater than
Answer: a
Explanation: In TDM the transmission rate provided by the path that is multiplexed will always be greater than the sum of transmission rates of the single sources. This happens because the transmission rate is provided to each source only for a small period of time.

37. In TDM, slots are further divided into _________
a) Seconds
b) Frames
c) Packets
d) Bits
Answer: b
Explanation: TDM is the abbreviation for Time division multiplexing. It is technique for combining several low rate channels to a single high rate channel. For a certain time slot, the several channels could use the maximum bandwidth. Each channel is inactive for a period of time too. Some other multiplexing techniques are Frequency division multiplexing and Phase division multiplexing.

38. Which of the following delay is faced by the packet in travelling from one end system to another?
a) Propagation delay
b) Queuing delay
c) Transmission delay
d) All of the mentioned
Answer: d
Explanation: When a packet has to travel from one end system to another, it first faces the queuing delay when there are multiple packets which are to be sent, then it faces the transmission delay to convert the packet into bits to be transmitted, and then it faces the propagation delay to propagate the bits through the physical medium.

39. For a 10Mbps Ethernet link, if the length of the packet is 32bits, the transmission delay is ____________ (in microseconds)
a) 3.2
b) 32
c) 0.32
d) 320
Answer: a
Explanation: Transmission rate = length / transmission rate = 32/10 = 3.2 microseconds.

40. The time required to examine the packet’s header and determine where to direct the packet is part of __________
a) Processing delay
b) Queuing delay
c) Transmission delay
d) Propagation delay
Answer: a
Explanation: Processing delay is induced at a router’s or other network processor’s end in the path of the packet and is caused by the time taken by the processor to examine the packet’s header to decide the further path of the packet.

42. Given L = number of bits in the packet, a = average rate and R = transmission rate. The Traffic intensity in the network is given by ____________
a) La/R
b) LR/a
c) R/La
d) Ra/L
Answer: a
Explanation: Traffic Intensity = (Number of bits in packet * Average Transmission rate)/Current Transmission rate.

43. In the transfer of file between server and client, if the transmission rates along the path is 10Mbps, 20Mbps, 30Mbps, 40Mbps. The throughput is usually ___________
a) 20Mbps
b) 10Mbps
c) 40Mbps
d) 50Mbps
Answer: b
Explanation: The throughput is generally the transmission rate of bottleneck link.

44. If end to end delay is given by dend-end = N(dproc + dtrans + dprop) is a non congested network. The number of routers between source and destination is?
a) N/2
b) N
c) N-1
d) 2N
Answer: c
Explanation: In the equation N (dproc + dtrans + dprop), N is the number of checkpoints/stops that the packet makes as it reaches the destination. The stops are made at each router and the final destination node. Now, since N = number of routers + final node, then number of routers = N – final node. As we know, there is only 1 final node in a path, thus, number of routers = N – 1. Suppose, There is a path A->R1->R2->B for a packet where A is the source node, B is the final node and R1 and R2 are routers. The total delay would be given by N (dproc + dtrans + dprop) where N = 3, since the packet would stop at R1, R2 and B. The number of routers here are 2, and (N – 1) is also 2.

45. The total nodal delay is given by ____________
a) dnodal = dproc – dqueue + dtrans + dprop
b) dnodal = dproc + dtrans – dqueue
c) dnodal = dproc + dqueue + dtrans + dprop
d) dnodal = dproc + dqueue – dtrans – dprop
Answer: c
Explanation: The total node-to-node delay, that is, nodal delay is the sum of all, the processing delay, queuing delay, transmission delay and propagation delay. Ideally, the nodal delay must be low as possible for a better Quality of Service of the network.

46. In a network, If P is the only packet being transmitted and there was no earlier transmission, which of the following delays could be zero?
a) Propagation delay
b) Queuing delay
c) Transmission delay
d) Processing delay
Answer: b
Explanation: Since there is no other packet to be transmitted, there is no need for a queue. Therefore, the delay caused due to the queuing would be none i.e. 0.

47. Transmission delay does not depend on _____________
a) Packet length
b) Distance between the routers
c) Transmission rate
d) Bandwidth of medium
Answer: b
Explanation: Transmission delay = packet length / transmission rate. The transmission rate depends upon the bandwidth of the medium.

48. Propagation delay depends on ___________
a) Packet length
b) Transmission rate
c) Distance between the routers
d) Speed of the CPU
Answer: c
Explanation: Propagation delay is caused when the packet is in its electric signal form and is travelling through a medium (a wire or a electromagnetic wave). Propagation delay is the time it takes a bit to propagate from one router to the next. If the distance between the routers is increased, it will take longer time to propagate, that is, there would be more propagation delay.

49. _____________ allows LAN users to share computer programs and data.
a) Communication server
b) Print server
c) File server
d) Network
Answer: c
Explanation: A file server allows LAN users to share computer programs and data. It uses the File Transfer Protocol to provide this feature on ports 20 and 21. The file server works as a medium for the transfer.

50. With respect to physical media, STP cables stands for _________
a) Shielded Twisted Pair Cable
b) Spanning Tree Protocol Cable
c) Static Transport Protocol Cable
d) Shielded Two Power Cable
Answer: a
Explanation: For physical media, STP cable stands for Shielded twisted pair cable. 100 Mbps is the max data capacity of STP cable and its default connector is RJ45. It is popularly used in LANs due to its ease of maintenance and installation.

51. A standalone program that has been modified to work on a LAN by including concurrency controls such as file and record locking is an example of ___________
a) LAN intrinsic software
b) LAN aware software
c) Groupware
d) LAN ignorant software
Answer: a
Explanation: A standalone program that has been modified to work on a LAN by including concurrency controls such as file and record locking is an example of LAN intrinsic software. They are used to give better functionality of the program and the applications working over it to the users of the LAN.

52. The __________ portion of LAN management software restricts access, records user activities and audit data, etc.
a) Configuration management
b) Security management
c) Performance management
d) Recovery management
Answer: b
Explanation: The Security management portion of LAN management software restricts access, records user activities, and audit data. It is responsible for controlling access to the network based on predefined policy. The security management ensures authentication, confidentiality, and integrity in the LAN.

53. What is the max length of the Shielded twisted pair cable?
a) 100 ft
b) 200 ft
c) 100 m
d) 200 m
Answer: c
Explanation: The max the Shielded twisted pair cable is 100 meters. If the length exceeds 100 meters, the loss of signals flowing through the cable would be really high. Thus, STP cable is more suitable for smaller networks like LANs.

54. What is the max data transfer rate of STP cables?
a) 10 Mbps
b) 100 Mbps
c) 1000 Mbps
d) 10000 Mbps
Answer: b
Explanation: 100 Mbps is the max data transfer rate that can be handled by STP cables, and its default connector is RJ-45. 100 Mbps is a feasible data transfer rate for small networks like LANs.

55. Which connector does the STP cable use?
a) BNC
b) RJ-11
c) RJ-45
d) RJ-69
Answer: c
Explanation: RJ-45 is used for STP cable. 100 Mbps is the max data transfer rate that can be handled by STP. RJ-45 is popularly used to connect to modern-day routers, computer network cards, and other network devices.

56. What is the central device in star topology?
a) STP server
b) Hub/switch
c) PDC
d) Router
Answer: b
Explanation: In star topology, no computer is connected to another computer directly but all the computers are connected to a central switch or hub. Every message sent from a source computer goes through the switch or hub and the switch or hub then forwards the message only to the intended destination computer.

57. What is the max data transfer rate for optical fiber cable?
a) 10 Mbps
b) 100 Mbps
c) 1000 Mbps
d) 10000 Mbps
Answer: d
Explanation: Fiber channel speeds have been increasing over the years. 10000 Mbps is the max data transfer rate for optical fiber cables. It is said to be the fastest among the other kinds of cables like STP cables and co-axial cables. People are now using optical fiber cables instead of STP cables for LANs due to their fast data transfer capability.

58. Which of the following architecture uses the CSMA/CD access method?
a) ARC net
b) Ethernet
c) Router
d) STP server
Answer: b
Explanation: Collision detection is not possible in Ethernet without extensions. Collision detection techniques for multiple access like CSMA/CD are used to detect collisions in the Ethernet architecture.

59. The attacker using a network of compromised devices is known as _____________
a) Internet
b) Botnet
c) Telnet
d) D-net
Answer: b
Explanation: Botnet is a network of compromised devices used by the attacker without the owner’s knowledge to perform unethical activities such as spamming. The attacker usually uses the least secure devices to create the botnet.

60. Which of the following is a form of DoS attack?
a) Vulnerability attack
b) Bandwidth flooding
c) Connection flooding
d) All of the mentioned
Answer: d
Explanation: In a DoS attack, the attacker won’t let the victims access the network by using a certain method that ensures that an essential network resource is unavailable to the victim. In vulnerability attack, the attacker exploits any obvious vulnerable entity in the network to deny the victim access into the network. In bandwidth flooding, the attacker floods the victim with a huge flow of packets and uses up all the bandwidth. In connection flooding, the attacker floods the victim network with a huge number of connections, so that, no other machine can connect to it.

61. The DoS attack, in which the attacker establishes a large number of half-open or fully open TCP connections at the target host is ________
a) Vulnerability attack
b) Bandwidth flooding
c) Connection flooding
d) UDP flooding
Answer: c
Explanation: In Vulnerability attack, the attacker exploits the vulnerable control points of the network to deny access to the victims. In Bandwidth flooding, the attacker intentionally uses up all the bandwidth by flooding the victim with a deluge of packets and makes sure that the victim can’t use any bandwidth. In UDP flooding, too many UDP packets are sent by the attacker to the victim at random ports.

62. The DoS attack, in which the attacker sends deluge of packets to the targeted host is ________
a) Vulnerability attack
b) Bandwidth flooding
c) Connection flooding
d) UDP flooding
Answer: b
Explanation: In Bandwidth flooding, the attacker floods the victim machine with a deluge of packets to make sure that no bandwidth is available. The victim then cannot utilize the complete bandwidth to perform its operation.

63. Packet sniffers involve ____________
a) Active receiver
b) Passive receiver
c) Legal receiver
d) Partially-active receiver
Answer: b
Explanation: The function of packet sniffers is to just silently receive the packets flowing in the channel. If they inject any packets into the channel, they might alert the other users about the intrusion.

64. Sniffers can be prevented by using _______________
a) Wired environment
b) WiFi
c) Ethernet LAN
d) Switched network
Answer: d
Explanation: Switches make sure that the packet is sent to the intended receiver and no one else, thus preventing Sniffers to perform their function. Intelligent switches are hence used preferably for the network.

65. Firewalls are often configured to block ___________
a) UDP traffic
b) TCP traffic
c) Sensitive traffic
d) Best-effort traffic
Answer: a
Explanation: UDP is more vulnerable to attacks, so firewalls are often configured to block suspicious UDP traffic.

66. In a network, If P is the only packet being transmitted and there was no earlier transmission, which of the following delays could be zero?
a) Propagation delay
b) Queuing delay
c) Transmission delay
d) Processing delay
Answer: b
Explanation: Since there is no other packet to be transmitted, there is no need for a queue. Therefore, the delay caused due to the queuing would be none i.e. 0.

67. Which of this is not a guided media?
a) Fiber optical cable
b) Coaxial cable
c) Wireless LAN
d) Copper wire
Answer: c
Explanation: Wireless LAN is unguided media.

68. UTP is commonly used in __________
a) DSL
b) FTTP
c) HTTP
d) None of the mentioned
Answer: a
Explanation: Unshielded twisted pair(UTP) is commonly used in home access.

69. Coaxial cable consists of _______ concentric copper conductors.
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: Coaxial cable has an inner conductor surrounded by a insulating layer, which is surrounded by a conducting shield. Coaxial cable is used to carry high frequency signals with low losses.

70. Fiber optics posses following properties __________
a) Immune electromagnetic interference
b) Very less signal attenuation
c) Very hard to tap
d) All of the mentioned
Answer: d
Explanation: In fibre optics the transmission of information is in the form of light or photons. Due to all above properties mentioned in options fibre optics can be submerged in water and are used at more risk environments.

71. If an Optical Carrier is represented as OC-n, generally the link speed equals(in Mbps) __________
a) n*39.8
b) n*51.8
c) 2n*51.8
d) None of the mentioned
Answer: b
Explanation: The base unit of transmission rates in optical fibre is 51.8 Mbits/s. So an optical carrier represented as OC-n has n*51.8 Mbits/s transmission speed. For eg. OC-3 has 3*51.8 Mbits/s speed.

72. Terrestrial radio channels are broadly classifed into _____ groups.
a) 2
b) 3
c) 4
d) 1
Answer: b
Explanation: The three types are those that operate over very short distance, those that operate in local areas, those that operate in the wide area.

73. Radio channels are attractive medium because __________
a) Can penetrate walls
b) Connectivity can be given to mobile user
c) Can carry signals for long distance
d) All of the mentioned
Answer: d
Explanation: Radio channels can penetrate walls, can be used to provide connectivity to mobile users and can also carry signals for long distances.

74. Geostationary satellites ___________
a) Are placed at a fixed point above the earth
b) Rotate the earth about a fixed axis
c) Rotate the earth about a varying axis
d) All of the mentioned
Answer: a
Explanation: They are placed in orbit at 36,000km above Earth’s surface.

75. A local telephone network is an example of a _______ network.
a) Packet switched
b) Circuit switched
c) Bit switched
d) Line switched
Answer: b
Explanation: Circuit switching is connection oriented switching technique, whereas in the case of packet switching, it is connectionless. Circuit switching is implemented in the Physical layer, whereas packet switching is implemented in the Network layer. Internet too is based on the concept of circuit switching.

76. Most packet switches use this principle ____________
a) Stop and wait
b) Store and forward
c) Store and wait
d) Stop and forward
Answer: b
Explanation: The packet switch will not transmit the first bit to outbound link until it receives the entire packet. If the entire packet is not received and the time-out period expires, the packet switch will inform the sender to resend the part of packet or the entire packet based on the algorithm being used.

77. If there are N routers from source to destination, the total end to end delay in sending packet P(L-> number of bits in the packet R-> transmission rate) is equal to ______________
a) N
b) (N*L)/R
c) (2N*L)/R
d) L/R
Answer: b
Explanation: The equation to find the end to end delay when no. of bits, transmission rate and no. of routers is given by (N*L)/R. The total end to end delay, that is, nodal delay is the sum of all, the processing delay, queuing delay, transmission delay and propagation delay.

78. What are the Methods to move data through a network of links and switches?
a) Packet switching and Line switching
b) Circuit switching and Line switching
c) Line switching and bit switching
d) Packet switching and Circuit switching
Answer: d
Explanation: Packet switching and Circuit switching are two different types of switching methods used to connect the multiple communicating devices with one another. Packet switching is used in conventional LAN systems and circuit switching is used in telephonic systems.

79. The required resources for communication between end systems are reserved for the duration of the session between end systems in ________ method.
a) Packet switching
b) Circuit switching
c) Line switching
d) Frequency switching
Answer: b
Explanation: In circuit switching, a physical path between the sender and receiver is established. This path is maintained until the connection is needed. Circuit switching is implemented in the Physical layer and is used in telephonic systems.

80. As the resources are reserved between two communicating end systems in circuit switching, ___________ is achieved.
a) authentication
b) guaranteed constant rate
c) reliability
d) store and forward
Answer: b
Explanation: Circuit switching is connection oriented and is always implemented in the physical layer. Once a path is set, all transmission occurs through the same path. It is used since the early times in telephonic systems.

81. In _________ systems, resources are allocated on demand.
a) packet switching
b) circuit switching
c) line switching
d) frequency switching
Answer: a
Explanation: In packet switching, the bits are received in out of order and need to be assembled at the receiver end, whereas in the case of Circuit switching, all the bits are received in order. All transmissions may not occur through the same path in case of packet switching.

82. Which of the following is not an application layer service?
a) Network virtual terminal
b) File transfer, access, and management
c) Mail service
d) Error control
Answer: d
Explanation: Application layer is the topmost layer in the OSI model. Network virtual terminal, mail service, file transfer, access and management are all services of the application layer. It uses protocols like HTTP, FTP, and DNS etc. to provide these services.

1. The network layer is concerned with __________ of data.
a) bits
b) frames
c) packets
d) bytes
Answer: c
Explanation: In computer networks, the data from the application layer is sent to the transport layer and is converted to segments. These segments are then transferred to the network layer and these are called packets. These packets are then sent to data link layer where they are encapsulated into frames. These frames are then transferred to physical layer where the frames are converted to bits.

2. Which one of the following is not a function of network layer?
a) routing
b) inter-networking
c) congestion control
d) error control
Answer: d
Explanation: In the OSI model, network layer is the third layer and it provides data routing paths for network communications. Error control is a function of the data link layer and the transport layer.

3. A 4 byte IP address consists of __________
a) only network address
b) only host address
c) network address & host address
d) network address & MAC address
Answer: c
Explanation: An ip address which is 32 bits long, that means it is of 4 bytes and is composed of a network and host portion and it depends on address class. The size of the host address and network address depends upon the class of the address in classful IP addressing.

4. In virtual circuit network each packet contains ___________
a) full source and destination address
b) a short VC number
c) only source address
d) only destination address
Answer: b
Explanation: A short VC number also called as VCID (virtual circuit identifier) is a type of identifier which is used to distinguish between several virtual circuits in a connection-oriented circuit-switched network. Each virtual circuit is used to transfer data over a larger packet-switched network.

5. Which of the following routing algorithms can be used for network layer design?
a) shortest path algorithm
b) distance vector routing
c) link state routing
d) all of the mentioned
Answer: d
Explanation: The routing algorithm is what decides where a packet should go next. There are several routing techniques like shortest path algorithm, static and dynamic routing, decentralized routing, distance vector routing, link state routing, Hierarchical routing etc. The routing algorithms go hand in hand with the operations of all the routers in the networks. The routers are the main participants in these algorithms.

6. Which of the following is not correct in relation to multi-destination routing?
a) is same as broadcast routing
b) contains the list of all destinations
c) data is not sent by packets
d) there are multiple receivers
Answer: c
Explanation: In multi-destination routing, there is more than one receiver and the route for each destination which is contained in a list of destinations is to be found by the routing algorithm. Multi-destination routing is also used in broadcasting.

7. A subset of a network that includes all the routers but contains no loops is called ________
a) spanning tree
b) spider structure
c) spider tree
d) special tree
Answer: a
Explanation: Spanning tree protocol (STP) is a network protocol that creates a loop free logical topology for ethernet networks. It is a layer 2 protocol that runs on bridges and switches. The main purpose of STP is to ensure that you do not create loops when you have redundant paths in your network.

8. Which one of the following algorithm is not used for congestion control?
a) traffic aware routing
b) admission control
c) load shedding
d) routing information protocol
Answer: d
Explanation: The Routing Information Protocol (RIP) is used by the network layer for the function of dynamic routing. Congestion control focuses on the flow of the traffic in the network and uses algorithms like traffic aware routing, admission control and load shedding to deal with congestion.

9. The network layer protocol for internet is __________
a) ethernet
b) internet protocol
c) hypertext transfer protocol
d) file transfer protocol
Answer: b
Explanation: There are several protocols used in Network layer. Some of them are IP, ICMP, CLNP, ARP, IPX, HRSP etc. Hypertext transfer protocol is for application layer and ethernet protocol is for data link layer.

10. ICMP is primarily used for __________
a) error and diagnostic functions
b) addressing
c) forwarding
d) routing
Answer: a
Explanation: ICMP abbreviation for Internet Control Message Protocol is used by networking devices to send error messages and operational information indicating a host or router cannot be reached. ICMP operates over the IP packet to provide error reporting functionality as IP by itself cannot report errors.

11. Open Shortest Path First (OSPF) is also called as _____________
a) Link state protocol
b) Error-correction protocol
c) Routing information protocol
d) Border gateway protocol
Answer: a
Explanation: In OSPF, the link state of each path is checked, and then the shortest path is chosen among only the open state links. Each OSPF router monitors the cost of the link to each of its neighbors and then floods the link state information to other routers in the network.

12. The computation of the shortest path in OSPF is usually done by ____________
a) Bellman-ford algorithm
b) Routing information protocol
c) Dijkstra’s algorithm
d) Distance vector routing
Answer: c
Explanation: Shortest path in OSPF is usually computed by Dijkstra’s algorithm. It was proposed by Edsger W. Dijkstra in the year 1956. It is a greedy method algorithm and hence may not guarantee the shortest path every time, but is really fast.

13. Which of the following is false with respect to the features of OSPF?
a) Support for fixed-length subnetting by including the subnet mask in the routing message
b) More flexible link cost than can range from 1 to 65535
c) Use of designated router
d) Distribution of traffic over multiple paths that have equal cost to the destination
Answer: a
Explanation: OSPF provides support for variable-length sunbathing by including the subnet mask in the routing message. For fixed length subnets, there is no requirement for including the subnet mask in the routing message as there is just one subnet mask for all the subnets.

14. In OSPF, which protocol is used to discover neighbour routers automatically?
a) Link state protocol
b) Error-correction protocol
c) Routing information protocol
d) Hello protocol
Answer: d
Explanation: Hello protocol is used to discover neighboring routers automatically. It makes sure that the communication between neighbors is bidirectional. It’s similar to the real world moral construct of saying “Hello” to initialize the communication.

15. Which of the following is not a type of OSPF packet?
a) Hello
b) Link-state request
c) Link-state response
d) Link-state ACK
Answer: c
Explanation: The five types of OSPF packets are: Hello, Database description, Link-state request, Link-state update, and Link-state ACK. There is no Link-state response packet; the neighbor router sends a Link-state update packet as a response to the Link-state request packet if there is an update in the routing table.

16. What is the correct order of the operations of OSPF?
i – Hello packets
ii – Propagation of link-state information and building of routing tables
iii – Establishing adjacencies and synchronization of database
a) i-ii-iii
b) i-iii-ii
c) iii-ii-i
d) ii-i-iii
Answer: b
Explanation: OSPF first implements a hello protocol. Then it later on tries to establish synchronisation with database. Later on building of routing tables is done.

17. In OSPF header, which field is used to detect errors in the packet?
a) Type
b) Area ID
c) Authentication type
d) Checksum
Answer: d
Explanation: Checksum field is used to detect errors. It makes sure that the data portions that are being sent are all in integrity. It can detect duplicated bits. Once an error is detected, the sender has to re-transmit the data as it won’t receive an acknowledgement.

18. In OSPF database descriptor packet, if there are more database descriptor packets in the flow, ‘M’ field is set to ____________
a) 1
b) 0
c) more
d) -1
Answer: a
Explanation: The “M” bit is the more bit, which indicates that there are more packets to be received in the descriptor packet flow whenever it is set to 1. There is also an “I” bit which indicates if the packet is first in the flow.

19. In OSPF database descriptor packet, which field is used to indicate that the router is master?
a) M
b) MS
c) I
d) Options
Answer: b
Explanation: The MS bit is used to indicate if the origin of the packet is a master or a slave. If it is set to 1, the source of the packet is a master, and if it is set to 0, the source of the packet is a slave.

20. In OSPF database descriptor packet, which field is used to detect a missing packet?
a) LSA header
b) MS
c) Database descriptor sequence number
d) Options
Answer: c
Explanation: Sequence number field is used to detect a missing packet. The packets are to be received in order of the sequence number, so if the receiver detects that there is a sequence number skipped or missing in the order, it stops processing the further received packets and informs the sender to retransmit the packets in sequence.

21. An OSPF router receives an LSA, the router checks its sequence number, and this number matches the sequence number of the LSA that the receiving router already has. What does the receiving router do with the LSA?
a) Ignores the LSA
b) Adds it to the database
c) Sends newer LSU update to source router
d) Floods the LSA to the other routers
Answer: a
Explanation: When the OSPF router receives an LSA, the router checks its sequence number. If this number matches the sequence number of the LSA that the receiving router already has, the router ignores the LSA.

22. An OSPF router receives an LSA. The router checks its sequence number and finds that this number is higher than the sequence number it already has. Which two tasks does the router perform with the LSA?
a) Ignores the LSA
b) Adds it to the database
c) Sends newer LSU update to source router
d) Floods the LSA to the other routers
Answer: b
Explanation: An OSPF router receives an LSA. If the router checks its sequence number and finds that the number is higher than the sequence number of the LSA that it already has, the router adds it to the database, and then floods the LSA to the other routers.

23. An OSPF router receives an LSA. The router checks its sequence number and finds that this number is lower than the sequence number it already has. What does the router do with the LSA?
a) ignores the LSA
b) adds it to the database
c) sends newer LSU update to source router
d) floods the LSA to the other routers
Answer: c
Explanation: An OSPF router receives an LSA. If the router checks its sequence number and finds that this number is lower than the sequence number that it already has, the router sends newer LSU update to source router. The router then adds it to the database and floods it to the other routers.

24. Each LSA has its own age timer. By default, how long does an LSA wait before requiring an update?
a) 30 seconds
b) 1 minute
c) 30 minutes
d) 1 hour
Answer: c
Explanation: Each LSA has its own age timer. By default, an LSA waits for 30 minutes before requiring an update. The router then has to send a LSR (Link State Request) to its neighbors to get an update.

25. Distance vector protocols use the concept of split horizon, but link-state routing protocols, such as OSPF, do not.
a) True
b) False
Answer: b
Explanation: In Distance vector routing protocols, there is a problem called count-to-infinity which occurs regularly. So, to make sure that it does not occur, the split horizon algorithm is used. There is no requirement for it in OSPF.

26. The outcome of Dijkstra’s calculation is used to populate the __________
a) Topology table
b) Routing table
c) Neighbor table
d) Adjacency table
Answer: b
Explanation: The outcome of Djikstra’s calculation is the main source of entries in the routing table as it is the algorithm that is used to find the shortest path in OSPF. The calculations are done after receiving every new LSU.

27. What is the IP protocol number for OSPF packets?
a) 89
b) 86
c) 20
d) 76
Answer: a
Explanation: 89 is the IP protocol number for OSPF packets. 86 is the protocol number for DGP, 76 is the protocol number for Backroom-SATNET-Monitoring and 20 is the protocol number for Host Monitoring Protocol.

28. Which packet is NOT an OSPF packet type?
a) LSU
b) LSR
c) DBD
d) Query
Answer: d
Explanation: LSU is the Link State Update packet, LSR is the Link State Request packet and DBD is the Database Descriptor packet in OSPF. Query packet is NOT an OSPF packet type.

29. Which multicast address does the OSPF Hello protocol use?
a) 224.0.0.5
b) 224.0.0.6
c) 224.0.0.7
d) 224.0.0.8
Answer: a
Explanation: Hello protocol is used to discover neighboring routers automatically. It makes sure that the communication between neighbors is bidirectional. The multicast address that the OSPF Hello protocol uses is 224.0.0.5.

30. The Hello protocol sends periodic updates to ensure that a neighbor relationship is maintained between adjacent routers.
a) True
b) False
Answer: a
Explanation: The Hello protocol sends periodic updates to ensure that a neighbor relationship is maintained between adjacent routers. It’s similar to the real world moral construct of saying “Hello” to initialize the communication.

31. Datagram switching is done at which layer of OSI model?
a) Network layer
b) Physical layer
c) Application layer
d) Transport layer
Answer: a
Explanation: Datagram switching is normally done at network layer. In datagram switching, the datagram stream need not be in order as each datagram can take different routes to the destination.

32. Packets in datagram switching are referred to as ________
a) Switches
b) Segments
c) Datagrams
d) Data-packets
Answer: c
Explanation: As the name suggests, in datagram switching packets are called as datagram. Each datagram/packet is treated as an individual entity and routed independently through the network.

33. Datagram networks mainly refers to _________
a) Connection oriented networks
b) Connection less networks
c) Telephone networks
d) Internetwork
Answer: b
Explanation: The switch does not keep the information about the connection state, hence it is connection less. There is no need for establishing a handshake to begin the transmission in such networks.

34. Datagrams are routed to their destinations with the help of ________
a) Switch table
b) Segments table
c) Datagram table
d) Routing table
Answer: c
Explanation: Routing table is used to route the packets to their destinations. The packet/datagram header contains the destination header for the whole journey to source to the destination through the routers.

35. The main contents of the routing table in datagram networks are ___________
a) Source and Destination address
b) Destination address and Output port
c) Source address and Output port
d) Input port and Output port
Answer: b
Explanation: Routing table contains destination address and output port to route the packets to their destinations. The port address specifies the particular application that the packet has to be forwarded to after it has reached the destination.

36. Which of the following remains same in the header of the packet in a datagram network during the entire journey of the packet?
a) Destination address
b) Source address
c) Checksum
d) Padding
Answer: a
Explanation: Destination address remains same in the header during the entire journey of the packet. There is no pre-decided route for the packets so each datagram/packet is treated as an individual entity and routed independently through the network.

37. Which of the following is true with respect to the delay in datagram networks?
a) Delay is greater than in a virtual circuit network
b) Each packet may experience a wait at a switch
c) Delay is not uniform for the packets of a message
d) All of the mentioned
Answer: d
Explanation: The delay of each packet in a datagram network is different as each packet might take a different route to the destination. The delay includes the propagation delay and the processing delay that is induced at each stop/switch that the packet encounters in its journey.

38. During datagram switching, the packets are placed in __________ to wait until the given transmission line becomes available.
a) Stack
b) Queue
c) Hash
d) Routing table
Answer: b
Explanation: When there are too many packets to be transmitted and the transmission line gets blocked while transmitting some packets, the remaining packets are stored in queue during delay and are served as first in first out. The delay is called as queuing delay.

39. The probability of the error in a transmitted block _________ with the length of the block
a) Remains same
b) Decreases
c) Increases
d) Is not proportional
Answer: c
Explanation: Probability of the error in a transmitted block increases with the length of the block. Hence, the blocks should be as short as possible for ideal transmission with low possibility of an error.

40. Which of the following is false with respect to the datagram networks?
a) Number of flows of packets are not limited
b) Packets may not be in order at the destination
c) Path is not reserved
d) Delay is the same for all packets in a flow
Answer: d
Explanation: The delay of each packet in a datagram network is different as each packet might take a different route to the destination. This happens because there is no pre-decided route for the packets.

41. Network layer firewall works as a __________
a) Frame filter
b) Packet filter
c) Content filter
d) Virus filter
Answer: b
Explanation: As you know, firewalls are available as hardware appliances, as software-only, or a combination of the two. In every case, the purpose of a firewall is to isolate your trusted internal network (or your personal PC) from the dangers of unknown resources on the Internet and other network connections that may be harmful. The firewall prevents unauthorized access to your internal, trusted network from outside threats.

42. Network layer firewall has two sub-categories as _________
a) State full firewall and stateless firewall
b) Bit oriented firewall and byte oriented firewall
c) Frame firewall and packet firewall
d) Network layer firewall and session layer firewall
Answer: a
Explanation: Most network layer firewalls can operate as stateful or stateless firewalls, creating two subcategories of the standard network layer firewall. Stateful firewalls have the advantage of being able to track packets over a period of time for greater analysis and accuracy — but they require more memory and operate more slowly. Stateless firewalls do not analyze past traffic and can be useful for systems where speed is more important than security, or for systems that have very specific and limited needs. For example, a computer that only needs to connect to a particular backup server does not need the extra security of a stateful firewall.

43. A firewall is installed at the point where the secure internal network and untrusted external network meet which is also known as __________
a) Chock point
b) Meeting point
c) Firewall point
d) Secure point
Answer: a
Explanation: A firewall can be a PC, a router, a midrange, a mainframe, a UNIX workstation, or a combination of these that determines which information or services can be accessed from the outside and who is permitted to use the information and services from outside. Generally, a firewall is installed at the point where the secure internal network and untrusted external network meet, which is also known as a chokepoint.

44. Which of the following is / are the types of firewall?
a) Packet Filtering Firewall
b) Dual Homed Gateway Firewall
c) Screen Host Firewall
d) Dual Host Firewall
Answer: a
Explanation: A firewall can be a PC, a midrange, a mainframe, a UNIX workstation, a router, or combination of these. Depending on the requirements, a firewall can consist of one or more of the following functional components: Packet-filtering router

45. A proxy firewall filters at _________
a) Physical layer
b) Data link layer
c) Network layer
d) Application layer
Answer: d
Explanation: The application firewall is typically built to control all network traffic on any layer up to the application layer. It is able to control applications or services specifically, unlike a stateful network firewall, which is – without additional software – unable to control network traffic regarding a specific application. There are two primary categories of application firewalls, network-based application firewalls and host-based application firewalls.

46. A packet filter firewall filters at __________
a) Physical layer
b) Data link layer
c) Network layer or Transport layer
d) Application layer
Answer: c
Explanation: In computing, a firewall is a network security system that monitors and controls the incoming and outgoing network traffic based on predetermined security rules.[1] A firewall typically establishes a barrier between a trusted, secure internal network and another outside network, such as the Internet, that is assumed not to be secure or trusted.[2] Firewalls are often categorized as either network firewalls or host-based firewalls.

47. What is one advantage of setting up a DMZ with two firewalls?
a) You can control where traffic goes in three networks
b) You can do stateful packet filtering
c) You can do load balancing
d) Improved network performance
Answer: c
Explanation: DMZ stands for De-Militarized Zone. In a topology with a single firewall serving both internal and external users (LAN and WAN), it acts as a shared resource for these two zones. So load balancing can be done by adding another firewall.

48. What tells a firewall how to reassemble a data stream that has been divided into packets?
a) The source routing feature
b) The number in the header’s identification field
c) The destination IP address
d) The header checksum field in the packet header
Answer: a
Explanation: The source routing feature provides a path address for the packet to help the firewall to reassemble the data stream that was divided into packets. After reassembling, the firewall can then filter the stream.

49. A stateful firewall maintains a ___________ which is a list of active connections.
a) Routing table
b) Bridging table
c) State table
d) Connection table
Answer: a
Explanation: The routing table basically gives the state of each connection i.e. whether the connection is active or not. A routing table ensures the best performance for the stateful firewall.

50. A firewall needs to be __________ so that it can grow proportionally with the network that it protects.
a) Robust
b) Expansive
c) Fast
d) Scalable
Answer: b
Explanation: The firewall has to be expansive because a network is expected to grow with time and if the firewall is unable to grow with it, the firewall won’t be able to handle the growing network traffic flow and will hence fail.

51. Complex networks today are made up of hundreds and sometimes thousands of _________
a) Documents
b) Components
c) Servers
d) Entities
Answer: b
Explanation: Complex networks today are made up of hundreds and sometimes thousands of components. For effective functioning of these thousands of components, good network management is essential.

52. Performance management is closely related to _________
a) Proactive Fault Management
b) Fault management
c) Reactive Fault Management
d) Preventive Fault Management
Answer: b
Explanation: Fault management is really closely related to performance management. It is important to ensure that the network handles faults as effectively as it handles it’s normal functioning to achieve better performance management.

53. Configuration management can be divided into two subsystems: reconfiguration and __________
a) Documentation
b) Information
c) Servers
d) Entity
Answer: a
Explanation: The documentation subsystem of configuration management handles the log making and reporting functions of the configuration management. It also reports the errors in the network caused by the configuration’s failure.

54. In Network Management System, the term that is responsible for controlling access to network based on predefined policy is called ___________
a) Fault Management
b) Secured Management
c) Active Management
d) Security Management
Answer: d
Explanation: In Network Management System, the term that is responsible for controlling access to the network based on predefined policy is called security management. The security management ensures authentication, confidentiality and integrity in the network.

55. Control of users’ access to network resources through charges is the main responsibility of ______________
a) Reactive Fault Management
b) Reconfigured Fault Management
c) Accounting Management
d) Security Management
Answer: c
Explanation: Control of users’ access to network resources through charges is the main responsibility of accounting management. The accounting management creates a log of the users activity on the network too and goes hand-in-hand with the configurations management.

56. The physical connection between an end point and a switch or between two switches is __________
a) Transmission path
b) Virtual path
c) Virtual circuit
d) Transmission circuit
Answer: a
Explanation: The physical connection between an end point and a switch or between two switches is transmission path. The transmission path is the physical roadway that the packet needs to propagate in order to travel through the network.

57. Which of the following networks supports pipelining effect?
a) Circuit-switched networks
b) Message-switched networks
c) Packet-switched networks
d) Stream-switched networks
Answer: c
Explanation: Packet switched network is most preferred for pipelining process. Pipelining exponentially reduces the time taken to transmit a large number of packets in the network.

58. In Network Management System, maps track each piece of hardware and its connection to the _________
a) IP Server
b) Domain
c) Network
d) Data
Answer: c
Explanation: Network is the main entity connecting different components in a place. A network map is made to track each component and its connection to the network to ensure better network management.

59. MIB is a collection of groups of objects that can be managed by __________
a) SMTP
b) UDP
c) SNMP
d) TCP/IP
Answer: c
Explanation: MIB stands for Management Information Base. Simple network management controls the group of objects in management information base. It is usually used with SNMP (Simple Network Management Protocol).

60. A network management system can be divided into ___________
a) three categories
b) five broad categories
c) seven broad categories
d) ten broad categories
Answer: b
Explanation: The five broad categories of network management are
• Fault Management
• Configuration Management
• Accounting (Administration)
• Performance Management
• Security Management.

61. Which of the following is not applicable for IP?
a) Error reporting
b) Handle addressing conventions
c) Datagram format
d) Packet handling conventions
Answer: a
Explanation: The Internet Protocol is the networking protocol which establishes the internet by relaying datagrams across network boundaries. ICMP is a supporting protocol for IP which handles the Error Reporting functionality.

62. Which of the following field in IPv4 datagram is not related to fragmentation?
a) Flags
b) Offset
c) TOS
d) Identifier
Answer: c
Explanation: TOS-type of service identifies the type of packets. It is not related to fragmentation but is used to request specific treatment such as high throughput, high reliability or low latency for the IP packet depending upon the type of service it belongs to.

63. The TTL field has value 10. How many routers (max) can process this datagram?
a) 11
b) 5
c) 10
d) 1
Answer: c
Explanation: TTL stands for Time to Live. This field specifies the life of the IP packet based on the number of hops it makes (Number of routers it goes through). TTL field is decremented by one each time the datagram is processed by a router. When the value is 0, the packet is automatically destroyed.

64. If the value in protocol field is 17, the transport layer protocol used is _____________
a) TCP
b) UDP
c) ICMP
d) IGMP
Answer: b
Explanation: The protocol field enables the demultiplexing feature so that the IP protocol can be used to carry payloads of more than one protocol type. Its most used values are 17 and 6 for UDP and TCP respectively. ICMP and IGMP are network layer protocols.

65. The data field cannot carry which of the following?
a) TCP segment
b) UDP segment
c) ICMP messages
d) SMTP messages
Answer: c
Explanation: Data field usually has transport layer segments, but it can also carry ICMP messages. SMTP is an application layer protocol. First it must go through the transport layer to be converted into TCP segments and then it can be inserted into IP packets.

66. What should be the flag value to indicate the last fragment?
a) 0
b) 1
c) TTl value
d) Protocol field value
Answer: a
Explanation: The Flag field in the IP header is used to control and identify the fragments. It contains three bits: reserved, don’t fragment and more fragments. If the more fragments bit is 0, it means that the fragment is the last fragment.

67. Which of these is not applicable for IP protocol?
a) is connectionless
b) offer reliable service
c) offer unreliable service
d) does not offer error reporting
Answer: b
Explanation: IP does not provide reliable delivery service for the data. It’s dependent upon the transport layer protocols like TCP to offer reliability.

68. Which of the following demerits does Fragmentation have?
a) complicates routers
b) open to DOS attack
c) overlapping of fragments.
d) all of the mentioned
Answer: d
Explanation: Fragmentation makes the implementation of the IP protocol complex and can also be exploited by attackers to create a DOS attack such as a teardrop attack. Fragmentation won’t be required if the transport layer protocols perform wise segmentation.

69. Which field helps to check rearrangement of the fragments?
a) offset
b) flag
c) ttl
d) identifer
Answer: a
Explanation: The Fragment Offset field specifies where the fragment fits in the original datagram. The offset of the first fragment will always be 0. The size of the field (13 bits) is 3-bits shorter than the size of the total length field (16 bits).

70. Which of these is not applicable for IP protocol?
a) Connectionless
b) Offer reliable service
c) Offer unreliable service
d) Does not offer error reporting
Answer: b
Explanation: IP does not provide reliable delivery service for the data. It’s dependent upon the transport layer protocols like TCP to offer reliability.

72. Which of the following demerits does Fragmentation have?
a) Complicates routers
b) Open to DOS attack
c) Overlapping of fragments
d) All of the mentioned
Answer: d
Explanation: Fragmentation makes the implementation of the IP protocol complex and can also be exploited by attackers to create a DOS attack such as a teardrop attack. Fragmentation won’t be required if the transport layer protocols perform wise segmentation.

73. Which field helps to check rearrangement of the fragments?
a) Offset
b) Flag
c) TTL
d) Identifier
Answer: a
Explanation: The Fragment Offset field specifies where the fragment fits in the original datagram. The offset of the first fragment will always be 0. The size of the field (13 bits) is 3-bits shorter than the size of the total length field (16 bits).

74. In classless addressing, there are no classes but addresses are still granted in ______
a) IPs
b) Blocks
c) Codes
d) Sizes
Answer: b
Explanation: In classless addressing, there are no classes but addresses are still granted in blocks. The total number of addresses in a block of classless IP addresses = 2(32 – CIDR_value).

75. In IPv4 Addresses, classful addressing is replaced with ________
a) Classless Addressing
b) Classful Addressing
c) Classful Advertising
d) Classless Advertising
Answer: a
Explanation: Classful addressing is replaced with classless addressing as a large ratio of the available addresses in a class in calssful addressing is wasted. In classless addressing, one can reserve the number of IP addresses required by modifying the CIDR value and make sure that not many addresses are wasted.

76. First address in a block is used as network address that represents the ________
a) Class Network
b) Entity
c) Organization
d) Codes
Answer: c
Explanation: First address in a block is used as network address that represents the organization. The network address can be found by AND’ing any address in the block by the default mask. The last address in a block represents the broadcast address.

77. In classful addressing, a large part of available addresses are ________
a) Organized
b) Blocked
c) Wasted
d) Communicated
Answer: c
Explanation: In classful addressing, a large part of available addresses are wasted. Thus to solve this classful addressing is replaced with classless addressing where one can reserve the number of IP addresses required by modifying the CIDR value and make sure that not many addresses are wasted.

78. Network addresses are a very important concept of ________
a) Routing
b) Mask
c) IP Addressing
d) Classless Addressing
Answer: c
Explanation: Network addresses are a very important concept of IP addressing. The first address in a block is used as network address that represents the organization. The network address can be found by AND’ing any address in the block or class by the default mask.

79. Which of this is not a class of IP address?
a) Class E
b) Class C
c) Class D
d) Class F
Answer: d
Explanation: Class F is not a class of IP addressing. There are only five classes of IP addresses: Class A (0.0.0.0 to 127.255.255.255), Class B (128.0.0.0 to 191.255.255.255), Class C (192.0.0.0 to 223.255.255.255), Class D (224.0.0.0 to 239.255.255.255), and Class E (240.0.0.0 to 255.255.255.255).

80. The size of an IP address in IPv6 is _________
a) 4 bytes
b) 128 bits
c) 8 bytes
d) 100 bits
Answer: b
Explanation: An IPv6 address is 128 bits long. Therefore, 2128 i.e. 340 undecillion addresses are possible in IPv6. IPv4 has only 4 billion possible addresses and IPv6 would be a brilliant alternative in case IPv4 runs out of possible new addresses.

81. The header length of an IPv6 datagram is ___________
a) 10bytes
b) 25bytes
c) 30bytes
d) 40bytes
Answer: d
Explanation: IPv6 datagram has fixed header length of 40bytes, which results in faster processing of the datagram. There is one fixed header and optional headers which may or may not exist. The fixed header contains the mandatory essential information about the packet while the optional headers contain the optional “not that necessary” information.

82. In the IPv6 header, the traffic class field is similar to which field in the IPv4 header?
a) Fragmentation field
b) Fast-switching
c) ToS field
d) Option field
Answer: c
Explanation: The traffic class field is used to specify the priority of the IP packet which is a similar functionality to the Type of Service field in the IPv4 header. It’s an 8-bit field and its values are not defined in the RFC 2460.

83. IPv6 does not use _________ type of address.
a) broadcast
b) multicast
c) anycast
d) unicast
Answer: a
Explanation: There is no concept of broadcast address in IPv6. Instead, there is an anycast address in IPv6 which allows sending messages to a group of devices but not all devices in a network. Anycast address is not standardized in IPv4.

84. Which among the following features is present in IPv6 but not in IPv4?
a) Fragmentation
b) Header checksum
c) Options
d) Anycast address
Answer: d
Explanation: There is an anycast address in IPv6 which allows sending messages to a group of devices but not all devices in a network. Anycast address is not standardized in IPv4.

85. The _________ field determines the lifetime of IPv6 datagram
a) Hop limit
b) TTL
c) Next header
d) Type of traffic
Answer: a
Explanation: The Hop limit value is decremented by one by a router when the datagram is forwarded by the router. When the value becomes zero the datagram is discarded. The field is 8-bits wide, so an IPv6 packet can live up to 255 router hops only.

86. Dual-stack approach refers to _________
a) implementing Ipv4 with 2 stacks
b) implementing Ipv6 with 2 stacks
c) node has both IPv4 and IPv6 support
d) implementing a MAC address with 2 stacks
Answer: c
Explanation: Dual-stack is one of the approaches used to support IPv6 in already existing systems. ISPs are using it as a method to transfer from IPv4 to IPv6 completely eventually due to the lower number of possible available addresses in IPv4.

87. Suppose two IPv6 nodes want to interoperate using IPv6 datagrams, but they are connected to each other by intervening IPv4 routers. The best solution here is ________
a) Use dual-stack approach
b) Tunneling
c) No solution
d) Replace the system
Answer: b
Explanation: The IPv4 routers can form a tunnel in which at the sender’s side, the IPv6 datagram is encapsulated in to IPv4, and at the receiver’s side of the tunnel, the IPv4 packet is stripped and the IPv6 packet is sent to the receiver.

88. Teredo is an automatic tunneling technique. In each client the obfuscated IPv4 address is represented by bits ______
a) 96 to 127
b) 0 to 63
c) 80 to 95
d) 64 to 79
Answer: a
Explanation: Teredo is a technique through which gives the possibility for full IPv6 network connectivity to IPv6 capable hosts which are currently on an IPv4 network. Bits 96 to 127 in the datagram represents obfuscated 1Pv4 address of the IPv4 network.

1. Which of the following is false with respect to TCP?
a) Connection-oriented
b) Process-to-process
c) Transport layer protocol
d) Unreliable
Answer: d
Explanation: TCP is a transport layer protocol that provides reliable and ordered delivery of a stream of bytes between hosts communicating via an IP network.

2. In TCP, sending and receiving data is done as _______
a) Stream of bytes
b) Sequence of characters
c) Lines of data
d) Packets
Answer: a
Explanation: TCP provides stream oriented delivery between hosts communicating via an IP network and there are no message boundaries. TCP can concatenate data from a number of send () commands into one stream of data and still transmit it reliably.

3. TCP process may not write and read data at the same speed. So we need __________ for storage.
a) Packets
b) Buffers
c) Segments
d) Stacks
Answer: b
Explanation: A TCP receiver has a receive buffer that is used to store the unprocessed incoming packets in case the sender is sending packets faster than the processing rate of the received packets.

4. TCP groups a number of bytes together into a packet called _______
a) Packet
b) Buffer
c) Segment
d) Stack
Answer: c
Explanation: A segment may be collection of data from many send () statements. TCP transmits each segment as a stream of bytes.

5. Communication offered by TCP is ________
a) Full-duplex
b) Half-duplex
c) Semi-duplex
d) Byte by byte
Answer: a
Explanation: Data can flow both the directions at the same time during a TCP communication hence, it is full-duplex. This is the reason why TCP is used in systems that require full-duplex operation such as e-mail systems.

6. To achieve reliable transport in TCP, ___________ is used to check the safe and sound arrival of data.
a) Packet
b) Buffer
c) Segment
d) Acknowledgment
Answer: d
Explanation: Acknowledgment mechanism is used to check the safe and sound arrival of data. The sender actively checks for acknowledgement from the receiver and once a specific time period has passed, it retransmits the data.

7. In segment header, sequence number and acknowledgement number fields refer to _______
a) Byte number
b) Buffer number
c) Segment number
d) Acknowledgment
Answer: a
Explanation: As TCP has to ensure ordered delivery of packets, sequence number and acknowledgement number are used to identify the byte number of the packet in the stream of bytes being transmitted.

8. Suppose a TCP connection is transferring a file of 1000 bytes. The first byte is numbered 10001. What is the sequence number of the segment if all data is sent in only one segment?
a) 10000
b) 10001
c) 12001
d) 11001
Answer: b
Explanation: The sequence number given to first byte of a segment, with respect to its order among the previous segments, is the sequence number of that segment.

9. Bytes of data being transferred in each connection are numbered by TCP. These numbers start with a _________
a) Fixed number
b) Random sequence of 0’s and 1’s
c) One
d) Sequence of zero’s and one’s
Answer: d
Explanation: One might expect the sequence number of the first byte in the stream to be 0, or 1. But that does not happen in TCP, Instead, the sender has to choose an Initial Sequence Number (ISN), which is basically a random 32 bit sequence of 0’s and 1’s, during the connection handshake.

10. The value of acknowledgement field in a segment defines _______
a) sequence number of the byte received previously
b) total number of bytes to receive
c) sequence number of the next byte to be received
d) sequence of zeros and ones
Answer: c
Explanation: The acknowledgement field in a segment defines the sequence number of the byte which is to be received next i.e. sequence number of byte that the sender should transmit next.

11. The receiver of the data controls the amount of data that are to be sent by the sender is referred to as ___________
a) Flow control
b) Error control
c) Congestion control
d) Error detection
Answer: a
Explanation: Flow control is done to prevent the receiver from being overflowed with data. It is done using various open-loop (prevention) methods and closed-loop (recovery) methods.

12. Size of TCP segment header ranges between ___________
a) 16 and 32 bytes
b) 16 and 32 bits
c) 20 and 60 bytes
d) 20 and 60 bits
Answer: c
Explanation: The size of the header can be 20 bytes at a minimum if there are no options and can go up to 60 bytes at maximum with 40 bytes in the options field. The header contains all the control information required to ensure ordered, error-free and reliable delivery of the segment.

13. Connection establishment in TCP is done by which mechanism?
a) Flow control
b) Three-Way Handshaking
c) Forwarding
d) Synchronization
Answer: b
Explanation: A three-way handshake allows both, the server and the client to choose their Initial Sequence Number and inform about it to the other party. This won’t be possible using the two-way handshake mechanism.

14. The server program tells its TCP that it is ready to accept a connection. This process is called ___________
a) Active open
b) Active close
c) Passive close
d) Passive open
Answer: d
Explanation: This is the first step in the Three-Way Handshaking process and is started by the server. Then the Client picks an ISN (Initial Sequence Number) and synchronizes (shares) it with the Server requesting a connection. The Server acknowledges the clients ISN, and then picks an ISN and synchronizes it with the Client. At last, the Client acknowledges the servers ISN.

15. A client that wishes to connect to an open server tells its TCP that it needs to be connected to that particular server. The process is called ___________
a) Active open
b) Active close
c) Passive close
d) Passive open
Answer: a
Explanation: This is the second step in the Three-Way Handshaking process and is done by the client once it finds the open server and picks an ISN. The Server acknowledges the clients request, and then picks an ISN and synchronizes it with the Client. At last, the Client acknowledges the servers ISN.

16. In Three-Way Handshaking process, the situation where both the TCP’s issue an active open is ___________
a) Mutual open
b) Mutual Close
c) Simultaneous open
d) Simultaneous close
Answer: c
Explanation: In simultaneous open situation, two nodes send an SYN signal to each other and start a TCP connection. Here, both TCP nodes transmit a SYNC+ACK segment to each other and a connection is established between them. This doesn’t happen usually, because both sides have to know which port on the other side to send to.

17. A malicious attacker sends a large number of SYNC segments to a server, pretending that each of them is coming from a different client by faking the source IP address in the datagram. Which type of attack is being performed in this situation?
a) SYNC flooding attack
b) Active attack
c) Passive attack
d) Denial-of-service attack
Answer: a
Explanation: SYNC flooding attack is a form of Denial of Service attack. Due to the overflow of SYNC segments sent to the server, the victims are not able to request for a connection to the server, thus resulting in Denial of Service.

18. SYNC flooding attack belongs to a type of security attack known as ___________
a) SYNC flooding attack
b) Active attack
c) Passive attack
d) Denial-of-service attack
Answer: d
Explanation: During SYNC flooding the system collapses and denies service to every request, making it a DoS attack. Some other DoS attacks are bandwidth flooding, connection flooding and UDP flooding.

19. The sizes of source and destination port address in TCP header are ___________ respectively.
a) 16-bits and 32-bits
b) 16-bits and 16-bits
c) 32-bits and 16-bits
d) 32-bits and 32-bits
Answer: b
Explanation: All port addresses are of 16 bits and they specify the type of service being used by the network entity. For example, port 21 is used for FTP connections and port 25 is used for ICMP connections.

20. What allows TCP to detect lost segments and in turn recover from that loss?
a) Sequence number
b) Acknowledgment number
c) Checksum
d) Both Sequence & Acknowledgment number
Answer: b
Explanation: TCP header contains separate fields for sequence number and acknowledgment number. Comparing these values is what allows TCP to detect lost segments and in turn recover from that loss. After detecting the lost segments, the recovery may require retransmission of the lost segments of data.

21. Which of the following is false with respect to UDP?
a) Connection-oriented
b) Unreliable
c) Transport layer protocol
d) Low overhead
Answer: a
Explanation: UDP is an unreliable, connectionless transport layer protocol that provides message-based data transmission. TCP is an example of connection-oriented protocols.

22. Return value of the UDP port “Chargen” is _______
a) String of characters
b) String of integers
c) Array of characters with integers
d) Array of zero’s and one’s
Answer: a
Explanation: Using Chargen with UDP on port 19, the server sends a UDP datagram containing a random number of characters every time it receives a datagram from the connecting host. The number of characters is between 0 and 512.

23. Beyond IP, UDP provides additional services such as _______
a) Routing and switching
b) Sending and receiving of packets
c) Multiplexing and demultiplexing
d) Demultiplexing and error checking
Answer: d
Explanation: De-multiplexing is the delivering of received segments to the correct application layer processes at the recipients end using UDP. Error checking is done through checksum in UDP.

24. What is the main advantage of UDP?
a) More overload
b) Reliable
c) Low overhead
d) Fast
Answer: c
Explanation: As UDP does not provide assurance of delivery of packet, reliability and other services, the overhead taken to provide these services is reduced in UDP’s operation. Thus, UDP provides low overhead, and higher speed.

25. Port number used by Network Time Protocol (NTP) with UDP is ________
a) 161
b) 123
c) 162
d) 124
Answer: b
Explanation: The Network Time Protocol is a clock synchronization network protocol implemented by using UDP port number 123 to send and receive time stamps.

26. What is the header size of a UDP packet?
a) 8 bytes
b) 8 bits
c) 16 bytes
d) 124 bytes
Answer: a
Explanation: The fixed size of the UDP packet header is 8 bytes. It contains four two-byte fields: Source port address, Destination port address, Length of packet, and checksum.

27. The port number is “ephemeral port number”, if the source host is _______
a) NTP
b) Echo
c) Server
d) Client
Answer: d
Explanation: Port numbers from 1025 to 5000 are used as ephemeral port numbers in Windows Operating System. Ephemeral port numbers are short-lived port numbers which can be used for clients in a UDP system where there are temporary clients all the time.

28. “Total length” field in UDP packet header is the length of _________
a) Only UDP header
b) Only data
c) Only checksum
d) UDP header plus data
Answer: d
Explanation: Total length is the 16 bit field which contains the length of UDP header and the data. The maximum value of the Total length field and the maximum size of a UDP datagram is 65,535 bytes (8 byte header + 65,527 bytes of data).

29. Which is the correct expression for the length of UDP datagram?
a) UDP length = IP length – IP header’s length
b) UDP length = UDP length – UDP header’s length
c) UDP length = IP length + IP header’s length
d) UDP length = UDP length + UDP header’s length
Answer: a
Explanation: A user datagram is encapsulated in an IP datagram. There is a field in the IP header that defines the total length of the IP packet. There is another field in the IP header that defines the length of the header. So if we subtract the length of the IP header that is encapsulated in the IP packet, we get the length of UDP datagram.

30. The ______ field is used to detect errors over the entire user datagram.
a) udp header
b) checksum
c) source port
d) destination port
Answer: b
Explanation: Checksum field is used to detect errors over the entire user datagram. Though it is not as efficient as CRC which is used in TCP, it gets the job done for the UDP datagram as UDP doesn’t have to ensure the delivery of the packet.

31. Which mode of IPsec should you use to assure the security and confidentiality of data within the same LAN?
a) AH transport mode
b) ESP transport mode
c) ESP tunnel mode
d) AH tunnel mode
Answer: b
Explanation: ESP transport mode should be used to ensure the integrity and confidentiality of data that is exchanged within the same LAN. ESP tunnel mode is comparatively more secure and should be used to assure the security of the data within different LANs.

32. Which two types of encryption protocols can be used to secure the authentication of computers using IPsec?
a) Kerberos V5
b) SHA
c) MD5
d) Both SHA and MD5
Answer: d
Explanation: SHA or MD5 can be used. Kerberos V5 is an authentication protocol, not an encryption protocol; therefore, answer A is incorrect. Certificates are a type of authentication that can be used with IPsec, not an encryption protocol; therefore, answer B is incorrect.

33. Which two types of IPsec can be used to secure communications between two LANs?
a) AH tunnel mode
b) ESP tunnel mode
c) Both AH tunnel mode and ESP tunnel mode
d) ESP transport mode
Answer: c
Explanation: The AH and ESP tunnel mode IPSec should be used for data transfer purpose, option d is for integrity & confidentiality purpose. Tunnel mode provides security for the entire original IP packet unlike transport mode which is not as secure as it only encrypts the data portion and not the whole packet.

34. ______ provides authentication at the IP level.
a) AH
b) ESP
c) PGP
d) SSL
Answer: a
Explanation: The Authentication Header (AH) authenticates the origin of data, and guarantees the integrity of the information that’s being sent using IPSec. It also provides anti-reply security.

35. IPsec defines two protocols: _______ and ________
a) AH; SSL
b) PGP; ESP
c) AH; ESP
d) PGP; SSL
Answer: c
Explanation: AH ensures that there is no retransmission of data from an unauthorized source, and protects against data tampering. ESP provides with content protection and ensures that there is integrity and confidentiality for the message.

36. IP Security operates in which layer of the OSI model?
a) Network
b) Transport
c) Application
d) Physical
Answer: a
Explanation: IPSec is a set of protocols used to provide authentication, data integrity and confidentiality between two machines in an IP network. In the TCP/IP model, it provides security at the IP layer i.e. the network layer.

37. ESP does not provide ________
a) source authentication
b) data integrity
c) privacy
d) error control
Answer: d
Explanation: The ESP provides data confidentiality, integrity and authentication. It provides confidentiality through encryption. ESP can operate in two modes, transport mode and tunnel mode.

38. In computer security _______ means that computer system assets can be modified only by authorized parities.
a) confidentiality
b) integrity
c) availability
d) authenticity
Answer: b
Explanation: Integrity means that computer system assets can be modified only by authorized parities. Confidentiality means that the assets can only be accessed by authorized parties. Availability refers to the accessibility of the resource to the authorized parties. Authenticity means that the asset is not unethically changed.

39. In computer security _______ means that the information in a computer system only be accessible for reading by authorized parities.
a) confidentiality
b) integrity
c) availability
d) authenticity
Answer: a
Explanation: Confidentiality means that the assets can only be accessed by authorized parties. Integrity means that computer system assets can be modified only by authorized parities. Availability refers to the accessibility of the resource to the authorized parties. Authenticity means that the asset is not unethically changed.

40. Which of the following organizations is primarily concerned with military encryption systems?
a) NSA
b) NIST
c) IEEE
d) ITU
Answer: a
Explanation: The NSA is primarily responsible for military encryption systems. The NSA designs evaluates, and implements encryption systems for the military and government agencies with high security needs.

41. Two broad categories of congestion control are
a) Open-loop and Closed-loop
b) Open-control and Closed-control
c) Active control and Passive control
d) Active loop and Passive loop
Answer: a
Explanation: Open loop congestion control techniques are used to prevent congestion before it even happens by enforcing certain policies. Closed loop congestion control techniques are used to treat congestion after it has happened.

42. In open-loop control, policies are applied to __________
a) Remove after congestion occurs
b) Remove after sometime
c) Prevent before congestion occurs
d) Prevent before sending packets
Answer: c
Explanation: Open loop congestion control techniques are used to prevent congestion before it even happens by enforcing certain policies. Retransmission policy, window policy and acknowledgement policy are some policies that might be enforced.

43. Retransmission of packets must not be done when _______
a) Packet is lost
b) Packet is corrupted
c) Packet is needed
d) Packet is error-free
Answer: d
Explanation: Retransmission refers to the sender having to resend the packet to the receiver. It needs to be done only when some anomaly occurs with the packet like when the packet is lost or corrupted.

44. In Go-Back-N window, when the timer of the packet times out, several packets have to be resent even some may have arrived safe. Whereas in Selective Repeat window, the sender resends ___________
a) Packet which are not lost
b) Only those packets which are lost or corrupted
c) Packet from starting
d) All the packets
Answer: b
Explanation: In Selective Repeat, the sender side uses a searching algorithm to find the packets which need to be retransmitted based on the negative acknowledgements received and then resends only those packets thus saving bandwidth.

45. Discarding policy is mainly done by _______
a) Sender
b) Receiver
c) Router
d) Switch
Answer: c
Explanation: The discarding policy adopted by the routers mainly states that the routers discard sensitive or corrupted packets that it receives, thus controlling the integrity of the packet flow. The discarding policy is adopted as an open loop congestion control technique.

46. Closed-Loop control mechanisms try to _________
a) Remove after congestion occurs
b) Remove after sometime
c) Prevent before congestion occurs
d) Prevent before sending packets
Answer: a
Explanation: In closed loop congestion control, methods are implemented to remove congestion after it occurs. Some of the methods used are backpressure and choke packet.

47. The technique in which a congested node stops receiving data from the immediate upstream node or nodes is called as _______
a) Admission policy
b) Backpressure
c) Forward signaling
d) Backward signaling
Answer: b
Explanation: In this closed loop congestion control technique, the congested node propagates in the opposite direction of the data flow to inform the predecessor node to reduce the flow of packets. This is why this technique is called a node-to-node congestion control technique.

48. Backpressure technique can be applied only to _______
a) Congestion networks
b) Closed circuit networks
c) Open circuit networks
d) Virtual circuit networks
Answer: d
Explanation: In Virtual circuit networks, each node knows the upstream node from which a flow data is coming. So, it makes possible for the congested node to track the source of the congestion and then inform that node to reduce the flow to remove congestion.

49. The packet sent by a node to the source to inform it of congestion is called _______
a) Explicit
b) Discard
c) Choke
d) Backpressure
Answer: c
Explanation: Choke packet is sent by a node to the source to inform it of congestion. Two choke packet techniques can be used for the operation called hop-by-hop choke packet and source choke packet.

50. In the slow-start algorithm, the size of the congestion window increases __________ until it reaches a threshold.
a) exponentially
b) additively
c) multiplicatively
d) suddenly
Answer: a
Explanation: In slow-start algorithm, the size of the congestion window increases exponentially until it reaches a threshold. When it reaches the threshold, it stops increasing and continues sending packets through the threshold window thus preventing congestion.

51. An RPC (remote procedure call) is initiated by the _________
a) server
b) client
c) client after the sever
d) a third party
Answer: b
Explanation: Remote Procedure Call is a method used for constructing distributed, client-server applications based on extending the conventional local procedure calling where the client initiates an RPC to start a connection process.

52. In RPC, while a server is processing the call, the client is blocked ________
a) unless the client sends an asynchronous request to the server
b) unless the call processing is complete
c) for the complete duration of the connection
d) unless the server is disconnected
Answer: a
Explanation: While the server is processing the call i.e. looking through the specifications, the client is blocked, unless the client sends an asynchronous request to the server for another operation.

53. A remote procedure call is _______
a) inter-process communication
b) a single process
c) a single thread
d) a single stream
Answer: a
Explanation: Remote procedure calls is a form of inter-process communication where the client initiates an RPC to start a connection process. It is used to construct distributed, client-server applications.

54. RPC allows a computer program to cause a subroutine to execute in _________
a) its own address space
b) another address space
c) both its own address space and another address space
d) applications address space
Answer: b
Explanation: RPC allows a computer program to cause a subroutine to execute in another address space which is usually the servers address space in a conventional client-server network.

55. RPC works between two processes. These processes must be ____________
a) on the same computer
b) on different computers connected with a network
c) on the same computer and also on different computers connected with a network
d) on none of the computers
Answer: c
Explanation: For the operation of RPC between two processes, it is mandatory that the processes are present on the same computer and also on different computers connected with its network.

56. A remote procedure is uniquely identified by _________
a) program number
b) version number
c) procedure number
d) all of the mentioned
Answer: d
Explanation: Each remote procedure can be uniquely identified by the program number, version number and the procedure number in the networks scope. The identifiers can be used to control the remote procedure by parties involved in the process.

57. An RPC application requires _________
a) specific protocol for client server communication
b) a client program
c) a server program
d) all of the mentioned
Answer: d
Explanation: The RPC technique for constructing distributed, client-server applications based on extending the conventional local procedure calling. It requires a client program, a server program and specific protocol for client server communication to build the system.

58. RPC is used to _________
a) establish a server on remote machine that can respond to queries
b) retrieve information by calling a query
c) establish a server on remote machine that can respond to queries and retrieve information by calling a query
d) to secure the client
Answer: c
Explanation: RPC or Remote Procedure Call is used to establish a server on remote machine that can respond to queries and to retrieve information by calling a query by other computers.

59. RPC is a _________
a) synchronous operation
b) asynchronous operation
c) time independent operation
d) channel specific operation
Answer: a
Explanation: RPC is a synchronous operation where the remote machine works in sync with the other machines to act as a server that can respond to queries called by the other machines.

60. The local operating system on the server machine passes the incoming packets to the ___________
a) server stub
b) client stub
c) client operating system
d) client process
Answer: a
Explanation: The local operating system on the server machine passes the incoming packets to the server stub which then processes the packets which contain the queries from the client machines for retrieving information.

1. Which is not a application layer protocol?
a) HTTP
b) SMTP
c) FTP
d) TCP
Answer: d
Explanation: TCP is transport layer protocol.

2. The packet of information at the application layer is called __________
a) Packet
b) Message
c) Segment
d) Frame
Answer: b
Explanation: For Application, Presentation and Session layers there is no data format for message. Message is message as such in these three layers. But when it comes to Transport, Network, Data and Physical layer they have data in format of segments, packets, frames and bits respectively.

3. Which one of the following is an architecture paradigms?
a) Peer to peer
b) Client-server
c) HTTP
d) Both Peer-to-Peer & Client-Server
Answer: d
Explanation: HTTP is a protocol.

4. Application developer has permission to decide the following on transport layer side
a) Transport layer protocol
b) Maximum buffer size
c) Both Transport layer protocol and Maximum buffer size
d) None of the mentioned
Answer: c
Explanation: Application layer provides the interface between applications and the network. So application developer can decide what transport layer to use and what should be its maximum buffer size.

5. Application layer offers _______ service.
a) End to end
b) Process to process
c) Both End to end and Process to process
d) None of the mentioned
Answer: a
Explanation: End to End service is provided in the application layer. Whereas process to process service is provided at the transport layer.

6. E-mail is _________
a) Loss-tolerant application
b) Bandwidth-sensitive application
c) Elastic application
d) None of the mentioned
Answer: c
Explanation: Because it can work with available throughput.

7. Pick the odd one out.
a) File transfer
b) File download
c) E-mail
d) Interactive games
Answer: d
Explanation: File transfer, File download and Email are services provided by the application layer and there are message and data oriented.

8. Which of the following is an application layer service?
a) Network virtual terminal
b) File transfer, access, and management
c) Mail service
d) All of the mentioned
Answer: d
Explanation: The services provided by the application layer are network virtual terminal, file transfer, access and management, mail services, directory services, various file and data operations.

9. To deliver a message to the correct application program running on a host, the _______ address must be consulted.
a) IP
b) MAC
c) Port
d) None of the mentioned
Answer: c
Explanation: IP address lets you know where the network is located. Whereas MAC address is a unique address for every device. Port address identifies a process or service you want to carry on.

10. Which is a time-sensitive service?
a) File transfer
b) File download
c) E-mail
d) Internet telephony
Answer: d
Explanation: Internet telephony is Loss-tolerant other applications are not.

11. The ____________ translates internet domain and host names to IP address.
a) domain name system
b) routing information protocol
c) network time protocol
d) internet relay chat
Answer: a
Explanation: Domain name system is the way the internet domain names are stored and translated to IP addresses. The domain names systems matches the name of website to ip addresses of the website.

12. Which one of the following allows a user at one site to establish a connection to another site and then pass keystrokes from local host to remote host?
a) HTTP
b) FTP
c) Telnet
d) TCP
Answer: c
Explanation: Telnet is used for accessing remote computers. Using telnet a user can access computer remotely. With Telnet, you can log on as a regular user with whatever privileges you may have been granted to the specific application and data on the computer.

13. Application layer protocol defines ____________
a) types of messages exchanged
b) message format, syntax and semantics
c) rules for when and how processes send and respond to messages
d) all of the mentioned
Answer: d
Explanation: Application layer deals with the user interface, what message is to be sent or the message format, syntax and semantics. A user has access to application layer for sending and receiving messages.

14. Which one of the following protocol delivers/stores mail to reciever server?
a) simple mail transfer protocol
b) post office protocol
c) internet mail access protocol
d) hypertext transfer protocol
Answer: a
Explanation: SMTP, abbreviation for Simple Mail Transfer Protocol is an application layer protocol. A client who wishes to send a mail creates a TCP connection to the SMTP server and then sends the mail across the connection.

15. The ASCII encoding of binary data is called
a) base 64 encoding
b) base 32 encoding
c) base 16 encoding
d) base 8 encoding
Answer: a
Explanation: Base64 is used commonly in a number of applications including email via MIME, and storing complex data in XML. Problem with sending normal binary data to a network is that bits can be misinterpreted by underlying protocols, produce incorrect data at receiving node and that is why we use this code.

16. Which one of the following is an internet standard protocol for managing devices on IP network?
a) dynamic host configuration protocol
b) simple network management protocol
c) internet message access protocol
d) media gateway protocol
Answer: b
Explanation: SNMP is a set of protocols for network management and monitoring. This protocol is included in the application layer. SNMP uses 7 protocol data units.

17. Which one of the following is not an application layer protocol?
a) media gateway protocol
b) dynamic host configuration protocol
c) resource reservation protocol
d) session initiation protocol
Answer: c
Explanation: Resource reservation protocol is used in transport layer. It is designed to reserve resources across a network for quality of service using the integrated services model.

18. Which protocol is a signaling communication protocol used for controlling multimedia communication sessions?
a) session initiation protocol
b) session modelling protocol
c) session maintenance protocol
d) resource reservation protocol
Answer: a
Explanation: SIP is a signaling protocol in which its function includes initiating, maintaining and terminating real time sessions. SIP is used for signaling and controlling multimedia sessions.

19. Which one of the following is not correct?
a) Application layer protocols are used by both source and destination devices during a communication session
b) HTTP is a session layer protocol
c) TCP is an application layer protocol
d) All of the mentioned
Answer: d
Explanation: HTTP is an application layer protocol. Whereas TCP is a transport layer protocol.

20. When displaying a web page, the application layer uses the _____________
a) HTTP protocol
b) FTP protocol
c) SMTP protocol
d) TCP protocol
Answer: a
Explanation: HTTP is abbreviation for hypertext transfer protocol. It is the foundation of data communication for world wide web. This protocol decides how the message is formatted and transmitted etc.

21. The number of objects in a Web page which consists of 4 jpeg images and HTML text is ________
a) 4
b) 1
c) 5
d) 7
Answer: c
Explanation: 4 jpeg images + 1 base HTML file.

22. The default connection type used by HTTP is _________
a) Persistent
b) Non-persistent
c) Can be either persistent or non-persistent depending on connection request
d) None of the mentioned
Answer: a
Explanation: By default the http connection is issued with persistent connection. In persistent connection server leaves connection open after sending response. As little as one RTT (Time for a small packet to travel from client to server and back) is required for all referenced objects.

23. The time taken by a packet to travel from client to server and then back to the client is called __________
a) STT
b) RTT
c) PTT
d) JTT
Answer: b
Explanation: RTT stands for round-trip time.

24. The HTTP request message is sent in _________ part of three-way handshake.
a) First
b) Second
c) Third
d) Fourth
Answer: c
Explanation: In first step client sends a segment to establish a connection with the server. In the second the step the client waits for the acknowledgement to be received from the server. After receiving the acknowledgement, the client sends actual data in the third step.

25. In the process of fetching a web page from a server the HTTP request/response takes __________ RTTs.
a) 2
b) 1
c) 4
d) 3
Answer: b
Explanation: By default the http connection will be persistent connection. Hence it will take only 1 RTT to fetch a webpage from a server.

26. The first line of HTTP request message is called _____________
a) Request line
b) Header line
c) Status line
d) Entity line
Answer: a
Explanation: The line followed by request line are called header lines and status line is the initial part of response message.

27. The values GET, POST, HEAD etc are specified in ____________ of HTTP message
a) Request line
b) Header line
c) Status line
d) Entity body
Answer: a
Explanation: It is specified in the method field of request line in the HTTP request message.

28. The __________ method when used in the method field, leaves entity body empty.
a) POST
b) SEND
c) GET
d) PUT
Answer: c
Explanation: There are two methods which help to request a response from a server. Those are GET and POST. In GET method, the client requests data from server. In POST method the client submits data to be processed to the server.

29. The HTTP response message leaves out the requested object when ____________ method is used
a) GET
b) POST
c) HEAD
d) PUT
Answer: c
Explanation: HEAD method is much faster than GET method. In HEAD method much smaller amount of data is transferred. The HEAD method asks only for information about a document and not for the document itself.

30. Find the oddly matched HTTP status codes
a) 200 OK
b) 400 Bad Request
c) 301 Moved permanently
d) 304 Not Found
Answer: d
Explanation: 404 Not Found.

31. Multiple objects can be sent over a TCP connection between client and server in a persistent HTTP connection.
a) True
b) False
Answer: a
Explanation: Persistent connections are kept active after completing transaction so that multiple objects can be sent over the same TCP connection.

32. HTTP is ________ protocol.
a) application layer
b) transport layer
c) network layer
d) data link layer
Answer: a
Explanation: HTTP is an Application layer protocol used to define how messages are formatted and transmitted through the World Wide Web.

33. In the network HTTP resources are located by
a) uniform resource identifier
b) unique resource locator
c) unique resource identifier
d) union resource locator
Answer: a
Explanation: The Uniform Resource Identifier is a name and locator for the resource to be located by the HTTP. The URLs and URNs are derived through the identifier.

34. HTTP client requests by establishing a __________ connection to a particular port on the server.
a) user datagram protocol
b) transmission control protocol
c) border gateway protocol
d) domain host control protocol
Answer: b
Explanation: HTTP clients perform requests using a TCP connection, because the TCP connection provides a more reliable service. UDP is not a reliable protocol, border gateway protocol is used on top of TCP, while domain host control protocol is a network layer protocol.

35. In HTTP pipelining ________________
a) multiple HTTP requests are sent on a single TCP connection without waiting for the corresponding responses
b) multiple HTTP requests can not be sent on a single TCP connection
c) multiple HTTP requests are sent in a queue on a single TCP connection
d) multiple HTTP requests are sent at random on a single TCP connection
Answer: a
Explanation: HTTP pipelining helps the client make multiple requests without having to waiting for each response, thus saving a lot of time and bandwidth for the client.

36. FTP server listens for connection on port number ____________
a) 20
b) 21
c) 22
d) 23
Answer: b
Explanation: Port 20 is used for FTP data. Port 22 is used for SSH remote login. Port 23 is used for TELNET.

37. In FTP protocol, client contacts server using ____ as the transport protocol.
a) transmission control protocol
b) user datagram protocol
c) datagram congestion control protocol
d) stream control transmission protocol
Answer: a
Explanation: The clients use the Transmission Control Protocol for FTP as it’s more reliable than UDP, DCCP, and SCTP, and reliability of file transfer is required to be as high as possible for FTP.

38. In Active mode FTP, the client initiates both the control and data connections.
a) True
b) False
Answer: b
Explanation: In Passive mode of FTP, the client initiates both data and control connections, while in Active mode, the client initiates the control connection and then the server initiates the data connection.

39. The File Transfer Protocol is built on ______________
a) data centric architecture
b) service oriented architecture
c) client server architecture
d) connection oriented architecture
Answer: c
Explanation: The FTP connection includes a Server and a Client which wish to share files. The server can have multiple clients at the same time while the client communicates with only one server at a time.

40. In File Transfer Protocol, data transfer cannot be done in ___________
a) stream mode
b) block mode
c) compressed mode
d) message mode
Answer: d
Explanation: In Stream mode, the data is transferred in a continuous stream. In Block mode, data is transferred after being divided into smaller blocks. In Compressed mode, data is transferred after being compressed using some compression algorithm.

41. When the mail server sends mail to other mail servers it becomes ____________
a) SMTP server
b) SMTP client
c) Peer
d) Master
Answer: b
Explanation: SMTP clients are the entities that send mails to other mail servers. The SMTP servers cannot send independent mails to other SMTP servers as an SMTP server. There are no masters or peers in SMTP as it is based on the client-server architecture.

42. If you have to send multimedia data over SMTP it has to be encoded into _______
a) Binary
b) Signal
c) ASCII
d) Hash
Answer: c
Explanation: Since only 7-bit ASCII codes are transmitted through SMTP, it is mandatory to convert binary multimedia data to 7-bit ASCII before it is sent using SMTP.

43. Expansion of SMTP is ________
b) Simple Message Transfer Protocol
c) Simple Mail Transmission Protocol
d) Simple Message Transmission Protocol
Answer: a
Explanation: SMTP or Simple Mail Transfer Protocol is an application layer protocol used to transport e-mails over the Internet. Only 7-bit ASCII codes can be sent using SMTP.

44. In SMTP, the command to write receiver’s mail address is written with the command _______
a) SEND TO
b) RCPT TO
c) MAIL TO
d) RCVR TO
Answer: b
Explanation: RCPT TO command is followed by the recipient’s mail address to specify where or to whom the mail is going to through the internet. If there is more than one receiver, the command is repeated for each address continually.

45. The underlying Transport layer protocol used by SMTP is ________
a) TCP
b) UDP
c) Either TCP or UDP
d) IMAP
Answer: a
Explanation: TCP is a reliable protocol, and Reliability is a mandatory requirement in e-mail transmission using SMTP.

46. Choose the statement which is wrong incase of SMTP?
a) It requires message to be in 7bit ASCII format
b) It is a pull protocol
c) It transfers files from one mail server to another mail server
d) SMTP is responsible for the transmission of the mail through the internet
Answer: b
Explanation: In SMTP, the sending mail server pushes the mail to receiving mail server hence it is push protocol. In a pull protocol such as HTTP, the receiver pulls the resource from the sending server.

47. Internet mail places each object in _________
a) Separate messages for each object
b) One message
c) Varies with number of objects
d) Multiple messages for each object
Answer: b
Explanation: It places all objects into one message as it wouldn’t be efficient enough if there are different messages for each object. The objects include the text and all the multimedia to be sent.

48. Typically the TCP port used by SMTP is _________
a) 25
b) 35
c) 50
d) 15
Answer: a
Explanation: The ports 15, 35 and 50 are all UDP ports and SMTP only uses TCP port 25 for reliability.

49. A session may include ________
a) Zero or more SMTP transactions
b) Exactly one SMTP transactions
c) Always more than one SMTP transactions
d) Number of SMTP transactions cant be determined
Answer: a
Explanation: An SMTP session consists of SMTP transactions only even if no transactions have been performed. But no transactions in the session might mean that the session is inactive or is just initiated.

50. Which of the following is an example of user agents for e-mail?
a) Microsoft Outlook
b) Facebook
c) Google
d) Tumblr
Answer: a
Explanation: Among the options, only Microsoft Outlook is an e-mail agent. Google is a search engine and Facebook, and Tumblr are social networking platforms. Gmail and Alpine are some other examples of e-mail agent.

51. The entire hostname has a maximum of ___________
a) 255 characters
b) 127 characters
c) 63 characters
d) 31 characters
Answer: a
Explanation: An entire hostname can have a maximum of 255 characters. Although each label must be from 1 to 63 characters long. Host name is actually a label that is given to a device in a network.

52. A DNS client is called _________
a) DNS updater
b) DNS resolver
c) DNS handler
d) none of the mentioned
Answer: b
Explanation: DNS client also known as DNS resolver also known as DNS lookup helps to resolve DNS requests using an external DNS server.

53. Servers handle requests for other domains _______
a) directly
b) by contacting remote DNS server
c) it is not possible
d) none of the mentioned
Answer: b
Explanation: Whenever a request is received at server from other domains, it handles this situation by contacting remote DNS server.

54. DNS database contains _______
a) name server records
b) hostname-to-address records
c) hostname aliases
d) all of the mentioned
Answer: d
Explanation: Domain Name system not only deals with mapping IP addresses with the hostname but also deals with exchange of information in the server.

55. If a server has no clue about where to find the address for a hostname then _______
a) server asks to the root server
b) server asks to its adjcent server
c) request is not processed
d) none of the mentioned
Answer: a
Explanation: Root name servers are actually very important and critical as they are the first step in translating human readable hostnames into IP addresses for carrying out communication.

56. Which one of the following allows client to update their DNS entry as their IP address change?
a) dynamic DNS
b) mail transfer agent
c) authoritative name server
d) none of the mentioned
Answer: a
Explanation: Dynamic DNS or in short DDNS or DynDNS helps in automatically updating a name server in the DNS. This does not require manual editing.

57. Wildcard domain names start with label _______
a) @
b) *
c) &
d) #
Answer: b
Explanation: A wildcard DNS record matches requests to a non existent domain name. This wildcard DNS record is specified by using asterisk “*” as the starting of a domain name.

58. The right to use a domain name is delegated by domain name registers which are accredited by _______
a) internet architecture board
b) internet society
c) internet research task force
d) internet corporation for assigned names and numbers
Answer: d
Explanation: The ICANN (Internet Corporation for Assigned Names and Numbers) deals with IP address space allocation, protocol identifier assignment, generic and country code Top Level domain name system management (gTLD and ccTLD).

59. The domain name system is maintained by _______
a) distributed database system
b) a single server
c) a single computer
d) none of the mentioned
Answer: a
Explanation: A domain name system is maintained by a distributed database system. It is a collection of multiple, logically interrelated databases distributed over a computer network.

60. Which one of the following is not true?
a) multiple hostnames may correspond to a single IP address
b) a single hostname may correspond to many IP addresses
c) a single hostname may correspond to a single IP address
d) none of the mentioned
Answer: c
Explanation: It need not be that a single hostname will correspond to a ip address. For example facebook.com and fb.com both correspond to same ip address. So there can be multiple hostnames for a single ip address

61. DHCP (dynamic host configuration protocol) provides __________ to the client.
a) IP address
b) MAC address
c) Url
d) None of the mentioned
Answer: a
Explanation: We use DHCP to allow the hosts to acquire their ip addresses dynamically which is better than visiting each and every host on the network and configure all of this information manually.

62. DHCP is used for ________
a) IPv6
b) IPv4
c) Both IPv6 and IPv4
d) None of the mentioned
Answer: c
Explanation: DHCP is used for both IPv4 and IPv6 addressing. With DHCP you get to let the hosts know about the change dynamically, and hosts update their info themselves.

63. The DHCP server _________
a) maintains a database of available IP addresses
b) maintains the information about client configuration parameters
c) grants a IP address when receives a request from a client
d) all of the mentioned
Answer: d
Explanation: Whenever a DHCP server gets a request from a client it responds with a DHCP offer containing IP address being offered, network mask offered, the amount of time that the client can use and keep it, the ip address of the DHCP server making this offer.

64. IP assigned for a client by DHCP server is
a) for a limited period
b) for an unlimited period
c) not time dependent
d) none of the mentioned
Answer: a
Explanation: The IP address offered to a client is only for a limited period of time. There is actually a certain amount of time that the client can use and keep this IP address.

65. DHCP uses UDP port _________ for sending data to the server.
a) 66
b) 67
c) 68
d) 69
Answer: b
Explanation: 67 is the UDP port number that is used as the destination port of a server. Whereas UDP port number 68 is used by the client.

66. The DHCP server can provide the _______ of the IP addresses.
a) dynamic allocation
b) automatic allocation
c) static allocation
d) all of the mentioned
Answer: d
Explanation: When a host acquires multiple offers of IP addresses from different DHCP servers, the host will broadcast a dhcp request identifying the server whose offer has been accepted.

67. DHCP client and servers on the same subnet communicate via _________
a) UDP broadcast
b) UDP unicast
c) TCP broadcast
d) TCP unicast
Answer: a
Explanation: DHCP actually employs a connectionless service, which is provided by UDP, since TCP is connection oriented. It is implemented with two UDP port numbers 67 and 68 for its operations.

68. After obtaining the IP address, to prevent the IP conflict the client may use _________
a) internet relay chat
b) broader gateway protocol
c) address resolution protocol
d) none of the mentioned
Answer: c
Explanation: ARP abbreviation for address resolution protocol is used for mapping IP addresses to MAC addresses that are present in the local network.

69. What is DHCP snooping?
a) techniques applied to ensure the security of an existing DHCP infrastructure
b) encryption of the DHCP server requests
c) algorithm for DHCP
d) none of the mentioned
Answer: a
Explanation: DHCP snooping is a security feature that is used in OS of a network in the layer 2. This technology prevents unauthorized DHCP servers offering IP addresses to DHCP clients.

70. If DHCP snooping is configured on a LAN switch, then clients having specific ______ can access the network.
a) MAC address
b) IP address
c) Both MAC address and IP address
d) None of the mentioned
Answer: c
Explanation: The DHCP snooping is done to prevent unauthorized IP addresses being offered by unauthorized servers. This features allows only specific mac addresses and IP addresses to access the network.

71. The application-level protocol in which a few manager stations control a set of agents is called ______
a) HTML
b) TCP
c) SNMP
d) SNMP/IP
Answer: c
Explanation: SNMP stands for Simple Network Management Protocol. It is an application-level protocol in which a few manager stations control a set of agents. It is used under the TCP/IP protocol suite and is used for managing devices on the internet.

72. Full duplex mode increases the capacity of each domain by ________
a) 10 to 20 mbps
b) 20 to 30 mbps
c) 30 to 40 mbps
d) 40 to 50 mbps
Answer: a
Explanation: In full duplex mode, both endpoints share a single channel bandwidth to achieve two-way transmission. This results in complete utilization of the band capacity increasing the capacity by 10 to 20 mbps than half-duplex mode.

73. Configuration management can be divided into which two subsystems?
a) Reconfiguration and documentation
b) Management and configuration
c) Documentation and dialing up
d) Configuration and dialing up
Answer: a
Explanation: The best current practices report is created by a management group to ensure the most effective configuration management. The group also makes a MIB (Management Information Base) module to help with the configuration management.

74. To use a Simple Network Management System, we need _______
a) Servers
b) IP
c) Protocols
d) Rules
Answer: d
Explanation: Rules are a collection of expression containing parameters to observe the attributes of the user’s device, and then execute some actions. It specifies the parameters for the managed objects inside the application and performs operations that would support the expression. The input of a rule may be many expressions or even a single expression that end in an output of single object invoking some action.

75. The main difference between SNMPv3 and SNMPv2 is _______
a) Management
b) Integration
c) Classification
d) Enhanced security
Answer: d
Explanation: SNMPv3 has introduced new cryptographic security, through which confidentiality is provided by encrypting packets and blocking intruders. It also ensures that the message is coming from a reliable source.

76. In Network Management System, the division that is responsible for controlling access to network based on a predefined policy is called _________
a) Fault Management
b) Secured Management
c) Active Management
d) Security Management
Answer: d
Explanation: Security management is also responsible to provide confidentiality, authentication and encryption in addition to controlling access to network. Without security management, the network and its traffic would be vulnerable to be exploited by attackers.

77. BER stands for ________
a) Basic Encoding Rules
b) Basic Encoding Resolver
c) Basic Encoding Rotator
d) Basic Encoding Router
Answer: a
Explanation: The Basic Encoding Rules are a set of rules that specify the guidelines to encode the SNMP messages in binary form. Each SNMP message is encoded into 3 parts namely data, length and type of message.

78. Control of the users’ access to network resources through charges is the main responsibility of ________
a) Reactive Fault Management
b) Reconfigured Fault Management
c) Accounting Management
d) Security Management
Answer: c
Explanation: The accounting management keeps track of the users and their access rights to the network and controls the user’s access by communicating with the security management. The accounting management takes support of the Management Information Block to perform its operations.

79. SNMP is the framework for managing devices in an internet using the ______
a) TCP/IP protocol
b) UDP
c) SMTP
d) None
Answer: a
Explanation: SNMP is a management protocol in which a few manager stations control a set of agents using the TCP/IP protocol suite. SNMP stands for Simple Network Management Protocol.

80. Structure of Management Information (SMI), is the guideline of ________
a) HTTP
b) SNMP
c) URL
d) MIB
Answer: b
Explanation: SMI was developed by the Storage Networking Industry Association (SNIA) and it defines a standard that can be manipulated by SNMP. Basically, it defines the standard format and hierarchy of management data which is used by the SNMP. It does not describe how the objects are to be managed.

81. The application layer protocol used by a Telnet application is ________
a) Telnet
b) FTP
c) HTTP
d) SMTP
Answer: a
Explanation: Telnet is an application layer protocol that provides access to the command-line interface on a remote host. Telnet stands for teletype network.

82. Which amongst the following statements is correct for “character at a time” mode?
a) Character processing is done on the local system under the control of the remote system
b) Most text typed is immediately sent to the remote host for processing
c) All text is echoed locally, only completed lines are sent to the remote host
d) All text is processed locally, and only confirmed lines are sent to the remote host
Answer: b
Explanation: In character at a time mode, the typed text is sent immediately to the remote host while the user is typing. Another mode used in Telnet is “Old line by line” mode in which only completed lines are sent to the remote host.

83. _______ allows you to connect and login to a remote computer
a) Telnet
b) FTP
c) HTTP
d) SMTP
Answer: a
Explanation: Telnet provides access to the command-line interface on a remote computer. One can login to the computer from the command-line interface.

84. Telnet is used for _______
a) Television on net
b) Network of Telephones
c) Remote Login
d) Teleshopping site
Answer: c
Explanation: Telnet is an application layer protocol that provides access to the command line interface of a remote computer that can be used to perform remote login.

85. Which one of the following is not correct?
a) telnet is a general purpose client-server program
b) telnet lets user access an application on a remote computer
c) telnet can also be used for file transfer
d) telnet can be used for remote login
Answer: c
Explanation: File Transfer Protocol is used for file transfer. Telnet provides access to the command-line interface on a remote host.

86. Which operating mode of telnet is full duplex?
a) default mode
b) server mode
c) line mode
d) character mode
Answer: c
Explanation: In line mode, terminal character processing is done on the client side but editing is enabled on the server side. Line mode reduces the number of packets and is useful for long delay networks.

87. If we want that a character be interpreted by the client instead of server _________
a) interpret as command (IAC) escape character has to be used
b) control functions has to be disabled
c) it is not possible
d) cli character has to be used
Answer: a
Explanation: The client must look at each byte that arrives and look for IAC escape character. If IAC is found, the client moves on to look for any other code or IAC. If the next byte is IAC – a single byte is presented by the client to the terminal. If IAC is followed by any other code than IAC, the client interprets this as a command.

1. VPN is abbreviated as __________
a) Visual Private Network
b) Virtual Protocol Network
c) Virtual Private Network
d) Virtual Protocol Networking
Answer: c
Explanation: A Virtual Private Network i.e. VPN is a technique used in networking or other intermediate networks for connecting computers and making them isolated remote computer networks, maintaining a tunnel of security and privacy.

2. __________ provides an isolated tunnel across a public network for sending and receiving data privately as if the computing devices were directly connected to the private network.
a) Visual Private Network
b) Virtual Protocol Network
c) Virtual Protocol Networking
d) Virtual Private Network
Answer: d
Explanation: A Virtual Private Network i.e. VPN is a technique used in networking or other intermediate networks for connecting computers and making them isolated remote computer networks, maintaining a tunnel of security and privacy.

3. Which of the statements are not true to classify VPN systems?
a) Protocols used for tunnelling the traffic
b) Whether VPNs are providing site-to-site or remote access connection
c) Securing the network from bots and malwares
d) Levels of security provided for sending and receiving data privately
Answer: c
Explanation: VPN systems have specific protocols for tunnelling the traffic, secure remote access connectivity as well as make sure how many levels of security it is providing for private data communication.

4. What types of protocols are used in VPNs?
a) Application level protocols
b) Tunnelling protocols
c) Network protocols
d) Mailing protocols
Answer: a
Explanation: All VPNs are formed with a combination of tunnelling protocols as well as encryption techniques for maintaining privacy and security.

5. VPNs uses encryption techniques to maintain security and privacy which communicating remotely via public network.
a) True
b) False
Answer: a
Explanation: All VPNs are formed with a combination of tunnelling protocols as well as encryption techniques for maintaining privacy and security.

6. There are _________ types of VPNs.
a) 3
b) 2
c) 5
d) 4
Answer: b
Explanation: VPNs are of two types. These are remote access VPNs & Site-to-site VPNs. Remote Access VPNs are used for business & home users. Site-to-site VPNs are mainly used in companies and firms with different geographical locations.

7. Site-to-site VPNs are also known as ________
a) Switch-to-switch VPNs
b) Peer-to-Peer VPNs
c) Point-to-point VPNs
d) Router-to-router VPNs
Answer: d
Explanation: Site-to-site VPNs are also known as Router-to-router VPNs. They are mainly used in companies and firms with different geographical locations.

8. _________ type of VPNs are used for home private and secure connectivity.
a) Remote access VPNs
b) Site-to-site VPNs
c) Peer-to-Peer VPNs
d) Router-to-router VPNs
Answer: a
Explanation: Remote access VPN allows individual users to connect to private networks at home and access resources remotely.

9. Which types of VPNs are used for corporate connectivity across companies residing in different geographical location?
a) Remote access VPNs
b) Site-to-site VPNs
c) Peer-to-Peer VPNs
d) Country-to-country VPNs
Answer: b
Explanation: Site-to-site VPNs are also known as Router-to-router VPNs which are typically used in companies and firms for connecting remotely different branches with different geographical locations.

10. Site-to-Site VPN architecture is also known as _________
a) Remote connection based VPNs
b) Peer-to-Peer VPNs
c) Extranet based VPN
d) Country-to-country VPNs
Answer: c
Explanation: Site-to-site VPN architecture is also known as extranet based VPNs because these type of VPNs are typically used to connect firms externally between different branches of the same company.

11. There are ________ types of VPN protocols.
a) 3
b) 4
c) 5
d) 6
Answer: d
Explanation: There are six types of protocols used in VPN. These are Internet Protocol Security or IPSec, Layer 2 Tunnelling Protocol (L2TP), Point – to – Point Tunnelling Protocol (PPTP), Secure Sockets Layer (SSL), OpenVPN and Secure Shell (SSH).

12. For secure connection, Remote access VPNs rely on ___________ and ____________
a) IPSec, SSL
b) L2TP, SSL
c) IPSec, SSH
d) SSH, SSL
Answer: a
Explanation: A remote-access VPN typically depends on either Secure Sockets Layer (SSL) or IP Security (IPsec) for a secure connection over public network.

13. A ______ can hide a user’s browsing activity.
a) Firewall
b) Antivirus
c) Incognito mode
d) VPN
Answer: d
Explanation: VPNs are used for hiding user’s browsing activities and maintain anonymity. This also helps in preventing user’s personal browsing data leakage and protects the leakage of browsing habits.

14. __________ masks your IP address.
a) Firewall
b) Antivirus
c) VPN
d) Incognito mode
Answer: c
Explanation: VPNs are used for masking user’s IP address and maintain anonymity. This protects leakage of IP address that almost every website grabs when a user opens a website.

15. _________ are also used for hides user’s physical location.
a) Firewall
b) Antivirus
c) Incognito mode
d) VPN
Answer: d
Explanation: VPNs are used for hiding your physical location which helps in maintaining anonymity. Using IP address and browsing habits, link search, your physical location can be traced.

16. Using VPN, we can access _______________
a) Access sites that are blocked geographically
b) Compromise other’s system remotely
c) Hide our personal data in the cloud
d) Encrypts our local drive files while transferring
Answer: a
Explanation: With the help of VPN, users can access and connect to sites that are kept blocked by the ISPs based on a specific geographic location.

17. Your router has the following IP address on Ethernet0: 172.16.2.1/23. Which of the following can be valid host IDs on the LAN interface attached to the router?
i. 172.16.1.100
ii. 172.16.1.198
iii. 172.16.2.255
iv. 172.16.3.0
a) i only
b) ii and iii only
c) iii and iv only
d) ii only
Answer: c
Explanation: The router’s IP address on the E0 interface is 172.16.2.1/23, which is 255.255.254.0. This makes the third octet a block size of 2. The router’s interface is in the 172.16.2.0 subnet, and the broadcast address is 172.16.3.255 because the next subnet is 172.16.4.0. The valid host range is 172.16.2.1 to 172.16.3.254. The router is using the first valid host address in the range.

18. Which two statements describe the IP address 10.16.3.65/23?
i. The subnet address is 10.16.3.0 255.255.254.0.
ii. The lowest host address in the subnet is 10.16.2.1 255.255.254.0.
iii. The last valid host address in the subnet is 10.16.2.254 255.255.254.0.
iv. The broadcast address of the subnet is 10.16.3.255 255.255.254.0.
a) i and iii
b) ii and iv
c) i, ii and iv
d) ii, iii and iv
Answer: b
Explanation: The mask 255.255.254.0 (/23) used with a Class A address means that there are 15 subnet bits and 9 host bits. The block size in the third octet is 2 (256 – 254). So this makes the subnets in the interesting octet 0, 2, 4, 6, etc., all the way to 254. The host 10.16.3.65 is in the 10.16.2.0 subnet. The next subnet is 10.16.4.0, so the broadcast address for the 10.16.2.0 subnet is 10.16.3.255. The valid host addresses are 10.16.2.1 to 10.16.3.254.

19. What is the maximum number of IP addresses that can be assigned to hosts on a local subnet that uses the 255.255.255.224 subnet mask?
a) 14
b) 15
c) 16
d) 30
Answer: d
Explanation: A /27 (255.255.255.224) is 3 bits on and 5 bits off. This provides 8 subnets, each with 30 hosts. Does it matter if this mask is used with a Class A, B, or C network address? Not at all. The number of host bits would never change.

20. You need to subnet a network into 5 subnets, each with at least 16 hosts. Which classful subnet mask would you use?
a) 255.255.255.192
b) 255.255.255.224
c) 255.255.255.240
d) 255.255.255.248
Answer: b
Explanation: You need 5 subnets, each with at least 16 hosts. The mask 255.255.255.240 provides 16 subnets with 14 hosts which is less than 15, so this will not work. The mask 255.255.255.224 provides 8 subnets, each with 30 hosts so this may work. The mask 255.255.255.192 provides 4 subnets, each with 60 hosts so this may work. Comparing both the possible masks, 255.255.255.224 provides the best answer.

21. If an Ethernet port on a router were assigned an IP address of 172.16.112.1/25, what would be the valid subnet address of this host?
a) 172.16.112.0
b) 172.16.0.0
c) 172.16.96.0
d) 172.16.255.0
Answer: a
Explanation: A /25 mask is 255.255.255.128. Used with a Class B network, the third and fourth octets are used for subnetting with a total of 9 subnet bits, 8 bits in the third octet and 1 bit in the fourth octet. Since there is only 1 bit in the fourth octet, the bit is either off or on-which is a value of 0 or 128. The host in the question is in the 0 subnet, which has a broadcast address of 127 since 128 is the next subnet

22. You have an interface on a router with the IP address of 192.168.192.10/29. Including the router interface, how many hosts can have IP addresses on the LAN attached to the router interface?
a) 6
b) 8
c) 30
d) 32
Answer: a
Explanation: A /29 (255.255.255.248), regardless of the class of address, has only 3 host bits. Six hosts are the maximum number of hosts on this LAN, including the router interface. Out of the 8 addresses possible with the host bits, the first and the last address are for the subnet id and broadcast address respectively.

23. What is the subnet id of a host with an IP address 172.16.66.0/21?
a) 172.16.36.0
b) 172.16.48.0
c) 172.16.64.0
d) 172.16.0.0
Answer: c
Explanation: A /21 is 255.255.248.0, which means we have a block size of 8 in the third octet, so we just count by 8 until we reach 66. The subnet in this question is 64.0. The next subnet is 72.0, so the broadcast address of the 64 subnet is 71.255.

24. The network address of 172.16.0.0/19 provides how many subnets and hosts?
a) 7 subnets, 30 hosts each
b) 8 subnets, 8,190 hosts each
c) 8 subnets, 2,046 hosts each
d) 7 subnets, 2,046 hosts each
Answer: b
Explanation: A CIDR address of /19 is 255.255.224.0. This is a Class B address, so that is only 3 subnet bits, but it provides 13 host bits, or 8 subnets, each with 8,190 hosts.

25. Which of the following is the broadcast address for a Class B network ID using the default subnetmask?
a) 172.16.10.255
b) 255.255.255.255
c) 172.16.255.255
d) 172.255.255.255
Answer: c
Explanation: In this case, the class B network ID is 172.16.0.0. We know that the default mask of a class B network is 255.255.0.0. If we OR any address in a network with the complement of the default mask (0.0.255.255), we get the broadcast address of the network. In this case, the result of OR would be 172.16.255.255.

26. You have an IP address of 172.16.13.5 with a 255.255.255.128 subnet mask. What is your class of address, subnet address, and broadcast address?
a) Class A, Subnet 172.16.13.0, Broadcast address 172.16.13.127
b) Class B, Subnet 172.16.13.0, Broadcast address 172.16.13.127
c) Class B, Subnet 172.16.13.0, Broadcast address 172.16.13.255
d) Class B, Subnet 172.16.0.0, Broadcast address 172.16.255.255
Answer: b
Explanation: We know that the prefix 172 lies in class B (128 to 191) of IPv4 addresses. From the subnet mask, we get that the class is divided into 2 subnets: 172.16.13.0 to 172.16.13.127 and 172.16.13.128 to 172.16.13.255. The IP 172.16.13.5 lies in the first subnet. So the starting address 172.16.13.0 is the subnet address and last address 172.16.13.127 is the broadcast address.

27. If you wanted to have 12 subnets with a Class C network ID, which subnet mask would you use?
a) 255.255.255.252
b) 255.255.255.255
c) 255.255.255.240
d) 255.255.255.248
Answer: c
Explanation: If you have eight networks and each requires 10 hosts, you would use the Class C mask of 255.255.255.240. Why? Because 240 in binary is 11110000, which means you have four subnet bits and four host bits. Using our math, we’d get the following:
24-2=14 subnets
24-2=14 hosts.

28. The combination of _________ and __________ is often termed the local address of the local portion of the IP address.
a) Network number and host number
b) Network number and subnet number
c) Subnet number and host number
d) Host number
Answer: c
Explanation: It is termed as the local address because the address won’t be applicable outside the subnet. Sub networking is implemented for remote sensing in transparent way from that host which is contained in the sub network which called a local operation.

29. _________ implies that all subnets obtained from the same subnet mask.
a) Static subnetting
b) Dynamic subnetting
c) Variable length subnetting
d) Dynamic length subnetting
Answer: a
Explanation: Static subnetting is used when the requirement is of same number of hosts in each subnet for the institution. The same subnet mask can be used to find the subnet id of each subnet. It is usually used to divide large networks into smaller parts.

30. State whether true or false.
i) A connection oriented protocol can only use unicast addresses.
ii) The any cast service is included in IPV6.
a) True, True
b) True, False
c) False, True
d) False, False
Answer: a
Explanation: In a connection oriented protocol, the host can only establish connection with another host on one unique channel, that’s why it can only use unicast addresses. In IPv6, there is an anycast address in IPv6 which allows sending messages to a group of devices but not all devices in a network.

31. __________ is a high performance fiber optic token ring LAN running at 100 Mbps over distances upto 1000 stations connected.
a) FDDI
b) FDDT
c) FDDR
d) FOTR
Answer: a
Explanation: FDDI stands for Fiber Distributed Data Interface. It is a set of standards for fiber optic token ring LANs running at 100 Mbps over distances up to 200 km in diameter and 1000 stations connected.

32. Which of the following are Gigabit Ethernets?
a) 1000 BASE-SX
b) 1000 BASE-LX
c) 1000 BASE-CX
d) All of the mentioned
Answer: d
Explanation: In computer networking, Gigabit Ethernet (GbE or 1 GigE) is a term describing various technologies for transmitting Ethernet frames at a rate of a gigabit per second (1,000,000,000 bits per second), as defined by the IEEE 802.3-2008 standard. It came into use beginning in 1999, gradually supplanting Fast Ethernet in wired local networks, as a result of being considerably faster.

33. _________ is a collective term for a number of Ethernet Standards that carry traffic at the nominal rate of 1000 Mbit/s against the original Ethernet speed of 10 Mbit/s.
a) Ethernet
b) Fast Ethernet
c) Gigabit Ethernet
d) Gigabyte Ethernet
Answer: b
Explanation: Fast Ethernet is a set of Ethernet Standards which were introduced in 1995, that carry traffic at the nominal rate of 1000 Mbit/s. 100BASE-TX is the most commonly used Fast Ethernet standard.

34. _________ is another kind of fibre optic network with an active star for switching.
a) S/NET
b) SW/NET
c) NET/SW
d) FS/NET
Answer: a
Explanation: A 50-MBd active star fiber optical Local area network (LAN) and its optical combiner and mixing rod splitter are presented. The limited power budget and relatively large tapping losses of light wave technology, which limit the use of fiber optics in tapped bus LAN topologies, are examined and proven tolerable in optical star topologies.