Q2➡| NET November 2021 Given below are two statements Statement I: Telnet, Ftp, Http are application layer protocol Statement II: The Iridium project was planned to launch 66 low orbit satellites. In light of the above statements, choose the correct answer from the options given below.
i ➥Both Statement I and Statement II are false
ii ➥ Both Statement I and Statement II are true
iii ➥Statement I is false but Statement II is true
Q5➡| NET November 2021 A message is encrypted using public key cryptography to send a message from sender to receiver. Which one of the following statements is True?
Q7➡| NET November 2021 Which of the following statements are true? A. X.25 is connection-oriented network B. X.25 doesn’t support switched virtual circuits. C. Frame relay service provides acknowledgements. D. Frame relay service provides detection of transmission errors. Choose the correct answer from the options given below:
Q8➡| NET November 2021 The address of class B host is to be split into subnets with 6-bit subnet number. What is the maximum number of subnets and the maximum number of hosts in each subnet?
i ➥62 subnets and 1022 hosts
ii ➥ 62 subnets and 262142 hosts
iii ➥64 subnets and 1024 hosts
iv ➥ 64 subnets and hosts 262142
Show Answer With Best Explanation
Answer: I Explanation: Class B : Out of 32 bits, Class B have Network id = 16 bits and Host id = 16 bits Calculation Given subnet bits = 6 bits Maximum number of the subnets = 26 – 2 = 62 Note that 2 is substracted because * all 0’s is used to represent Network and * all 1’s is used to represent Broadcast Address of Network. Maximum number of hosts in each subnet Host id bits = 32 – (Network id bit + subnet id bits) = 32 – (16+ 6) = 10 Maximum number of hosts in each subnet = 210– 2 = 1022 Note that 2 is substracted because * all 0’s is used to represent Subnet and * all 1’s is used to represent Broadcast Address of Subnet. So, Option(I) is correct.
Q9➡| NET November 2021 Which of the following statements are true? A.Frequency division multiplexing technique can be handled by digital circuits. B.Time division multiplexing technique can be handled by analog circuits C. Wavelength division multiplexing technique is used with optical fiber for combining two signals. D. Frequency division multiplexing technique can be applied when the bandwidth of a link is greater than the bandwidth of the signals to be transmitted. Choose the correct answer from the options given below:
Calculation, 1) Two prime numbers p =3 , q=11 2) Calculate n = p*q = 3*11 = 33 3) Calculate ϕ(n) = (p-1)*(q-1) = (3-1)*(11-1) = 2*10=20 4) Calculate d , =>e*d mod ϕ(n) ==1 =>e*7 mod 20 ==1 => 3*7 mod 20 ==1 {if we take value of e is 3 , then reminder will be 1} 5) public key (e) = 3
Now, Calculate Ciphertext using key : Ciphertext = (Plaintext)e mod n = 193 mod 33 =28
Q11➡ | NET November 2020 Given below are two statements: Statement I: In Caesar Cipher each letter of Plain text is replaced by another letter for encryption. Statement II: Diffie-Hellman algorithm is used for exchange of secret key.
In the light of the above statements, choose the correct answer from the options given below:
i ➥Both Statement I and Statement II are true
ii ➥ Both Statement I and Statement II are false
iii ➥ Statement I is correct but Statement II is false
iv ➥Statement I is incorrect but Statement II is true
Q12➡ | NET November 2020 Firewall is a device that filters access to the protected network from the outside network. Firewall can filter the packets on the basis of (A) Source IP address (B) Destination IP Address (C) TCP Source Port (D) UDP Source Port (E) TCP Destination Port
Choose the correct answer from the options given below:
Q14➡ | NET November 2020 Protocols in which the sender sends one frame and then waits for an acknowledgement before proceeding for the next frame are called as___.
Q15➡ | NET November 2020 Post office protocol (POP) is a message access protocol which is used to extract messages for clients. In this regard, which of the following are true? A) POP has two modes, Delete mode and keep B) In Delete mode, mail is deleted from mailbox after each retrieval C) In Delete mode, mail is deleted from the mailbox before each retrieval. D) In keep mode, mail is deleted before retrieval. E) In keep mode, mail remains in the mailbox after retrieval.
Choose the correct answer from the options given below:
i ➥(A) and (B) only
ii ➥ (A), (D) and (E) only
iii ➥(A), (B), (C) and (D) only
iv ➥(A), (B) and (E) only
Show Answer With Best Explanation
Answer: IV Explanation:
POP has two modes: i)Delete Mode – A mail is deleted from the mailbox on the mail server after successful retrieval. (Delete after reading) ii)Keep Mode – A mail remains in the mailbox on the mail server after successful retrieval. (Store even after reading)
Q17➡ | NET December 2019 Which of the following is not needed by an encryption algorithm used in Cryptography? A) KEY B) Message C) Ciphertext D) User details
i ➥ (C) only
ii ➥(D) only
iii ➥(B) , (C) and (D) only
iv ➥(C) and (D) only
Show Answer With Best Explanation
Answer: IV
Explanation: Concept: In cryptography, • To encrypt a message, we need an encryption algorithm & To decrypt a message, we need a decryption algorithm. • Encryption algorithm convert plaintext into ciphertext & Decryption algorithm convert ciphertext into plaintext. • For Encryption algorithm, we need an encryption key, and the plaintext. • For Decryption algorithm, we need a decryption key, and the ciphertext.
Ciphertext & user details are not needed by encryption algorithm.
Q18➡ | NET December 2019 A network with a bandwidth of 10 Mbps can pass only an average of 12,000 frames per minute with each frame carrying an average of 10,000 bits. What is the throughput of this network?
i ➥ 1,000,000 bps
ii ➥ 2,000,000 bps
iii ➥12,000,000 bps
iv ➥1,200,00,000 bps
Show Answer With Best Explanation
Answer: II Explanation: Given, Bandwidth = 10 Mbps = 10 x 106bps Frame per minutes = 12,000 Frame per min Frame size = 10,000 bits
Ask, Throughput = ?
Throughput:: In data Transmission, network throughput tells how much data was transferred from a source at any given time & typically measured in bps, as in Mbps or Gbps.
Caculation: Throughput = Frames per minute * each Frame size = 12,000 per minute* 10,000 bits = 12,000 * 10,000 bits per minute = (12,000 * 10,000 / 60) bits per second = 2,000,000 bps = 2 Mbps
Q19➡ | NET December 2019 Consider the following statements with respect to network security: (a) Message confidentiality means that the sender and the receiver expect privacy. (b) Message integrity means that the data must arrive at the receiver exactly as they were sent. (c) Message authentication means the receiver is ensured that the message is coming from the intended sender.
Which of the statements is (are) correct?
i ➥ Only (a) and (b)
ii ➥ Only (a) and (c)
iii ➥ Only (b) and (c)
iv ➥(a), (b) and (c)
Show Answer With Best Explanation
Answer: IV Explanation:
Confidentiality • Confidentiality means that only the authorized individuals/systems can view sensitive or classified information. • The data being sent over the network should not be accessed by unauthorized individuals. • Confidentiality means that the sender and the receiver expect privacy.
Integrity • Data integrity means maintaining and assuring the accuracy and completeness of data over its entire lifecycle. • Integrity means that the data must arrive at the receiver exactly as they were sent.
Authentication • Authentication is the process of determining whether someone is who it is declared to be. • Authentication means the receiver is ensured that the message is coming from the intended sender.
Q20➡ | NET December 2019 Piconet is a basic unit of a Bluetooth system consisting of _______ master node and up to ________ active salve nodes.
i ➥ one, five
ii ➥one, seven
iii ➥ two, eight
iv ➥one, eight
Show Answer With Best Explanation
Answer: II
Explanation: • A piconet is a wireless set of devices make of use Bluetooth technology protocols. • A piconet is connection of two or more devices occupying the same physical. • A piconet is a combination of one master device( any device whis share the resource) and seven active slave devices(devices connected to the master device like phone,printer,speaker,scanner,mic etc) which has maximum 255 further slave devices can be inactive.
Other topic related to Piconet is Scatternet.
Scatternet -> sactternet is combination of Piconet.
So the correct answer is Option(II). (One Master and Seven Slave Devices )
For more details about Piconet Please Visit the More Discussion
i ➥ Internet Corporation for Assigned Names and Numbers
ii ➥ Internet Corporation for Assigned Names and Names
iii ➥Institute of Corporation for Assigned Names and Numbers
iv ➥Internet connection for Assigned Names and Numbers
Show Answer With Best Explanation
Answer: I Explanation:
ICANN (Internet Corporation for Assigned Name and Numbers)is non-profit organization that was formed in 1998. ICANN maintains the central repository for IP Addresses & help coordinate the supply the IP Addresses. It also manages the domain name system & root servers.
Q22➡ | NET December 2019 Consider a subnet with 720 routers. If a three-level hierarchy is chosen, with eight clusters, each containing 9 regions of 10 routers, then the total number of entries in hierarchical table of each router is
i ➥ 25
ii ➥ 27
iii ➥ 53
iv ➥72
Show Answer With Best Explanation
Answer: I
Explanation: Let’s try to understand the basic, In distance vector & link state routing, router have routing table & router have to store information about other router. As networks grow in size, number of router increases in network. Due to this, router can’t handle network traffic efficiently. So, routing will have to done hierarchically.
In three level hierarchically routing, Group of routers are called region & Group of regions are called cluster.
Given: Number of cluster = 8 cluster Each cluster have 9 regions. Each region have 10 routers.
Total number of entries in hierarchically table of each router =10 entries for router + 8 entries for routing to other regions within own cluster + 7 entries for distant clusters =10 + 8 + 7 =25
or
Total number of entries in hierarchically table of each router = Total nmber of router in a region + (Number of regions – 1) +(Number of clusters -1) =10 + 8 + 7 =25
Q23➡ | NET December 2019 Consider the following statements : (a) Fiber optic cable is much lighter than copper cable. (b) Fiber optic cable is not affected by power surges or electromagnetic interference. (c) Optical transmission is inherently bidirectional. Which of the statements is (are) correct?
Q25➡ | NET June 2019 What percentage(%) of the IPv4, IP address space do all class C addresses consume?
i ➥ 12.5%
ii ➥ 25%
iii ➥ 37.5%
iv ➥ 50%
Show Answer With Best Explanation
Answer: I
Explanation: Classful IP addresses is divided into classes. The leading bits of classes are: Class A – 0 Class B – 10 Class C – 110 Class D – 1110 Class E – 1111
On the basis of percentage, address space consume by all classes are: Class A – 50% Class B – 25% Class C – 12.5% Class D – 6.25% Class E – 6.25%
Q27➡ | NET June 2019 What is the name of the protocol that allows a client to send a broadcast message with its MAC address and receive an IP address in reply?
i ➥ ARP
ii ➥ DNS
iii ➥ RARP
iv ➥ ICMP
Show Answer With Best Explanation
Answer: III
Explanation: ARP : • Address Resolution Protocol [ARP] is a network layer protocol that is used to convert IP address into MAC address. • ARP is protocol that allows a client to send a broadcast message with its IP address and receive an MAC address in reply.
DNS: • DNS stands for Domain Name System. • DNS is a service that translates the domain name into IP addresses. • For example, the domain name www.samagraCS.com has a IP address 162.0.215.21(Suppose) • Where, www is a particular host server. • The com part of the domain name reflects the purpose of the organization or entity (in this example, commercial) and is called the top-level domain name. • The samagraCS part of the domain name defines the organization and together with the top-level is called the second-level domain name.
RARP: • Reverse Address Resolution Protocol (RARP) is a network layer protocol used to convert an IP address from a given physical address. • RARP is the complement of ARP. • “RARP is a protocol that allows a client to send a broadcast message with its MAC address and receive an IP address in reply”.
ICMP: • The ICMP stands for Internet Control Message Protocol. • ICMP is a network level protocol. • ICMP (Internet Control Message Protocol) is an error-reporting protocol that network devices such as routers use to generate error messages to the source IP address when network problems prevent delivery of IP packets.
Q28➡ | NET June 2019 The RSA encryption algorithm also works in reverse, that is, you can encrypt a message with the private key and decrypt it using the public key. This property is used in
Q29➡ | NET June 2019 You are designed a link layer protocol for a link with bandwidth of 1 Gbps (109 bits/second) over a fiber link with length of 800 km. Assume the speed of light in this medium is 200000 km/second. What is the propagation delay in this link?
i ➥ 1 millisecond
ii ➥ 2 millisecond
iii ➥ 3 millisecond
iv ➥ 4 millisecond
Show Answer With Best Explanation
Answer: IV
Explanation: Given: Bandwidth (Bw) = 1Gbps = 109 bps Link Length or Distance (d) = 800 Km Speed or velocity (v) = 200,000 Km / Sec
Propogation Delay: It is a measure of the time required for asignal to propogate from one end of circuit to other end.
Q30➡ | NET June 2019 Consider the following two statements with respect to IPv4 in computer networking: P: The loopback(IP) address is a member of class B network Q: The loopback(IP) address is used to send a packet from host to itself What can you say about the statements P and Q?
i ➥ P-True; Q-False
ii ➥ P-False; Q-True
iii ➥ P-True; Q-True
iv ➥ P-False; Q-false
Show Answer With Best Explanation
Answer: II
Explanation: Loopback address • A loopback address is a special IP address, 127.0.0.1, reserved by InterNIC for use in testing network cards. • A loopback address works is that a data packet will get sent through a network and routed back to the same device where it originated. • In IPv4, 127.0.0.1 is the most commonly used loopback address, however, this can range be extended to 127.255.255.255. • The loopback (IP) address is used to send a packet from host to itself & check NIC working or not. • The loopback (IP) address is a member of class A network. (IP Address of Class A network range from 0.0.0.0 to 127.255.255.255)
Statement P: The loopback(IP) address is a member of class B network (False). Because, The loopback(IP) address is a member of class A network.
Statement Q: The loopback(IP) address is used to send a packet from host to itself (True)
Q32➡ | NET June 2019 You need 500 subnets, each with about 100 usable host addresses per subnet. What network mask will you assign using a class B network address?
i ➥ 255.255.255.252
ii ➥ 255.255.255.128
iii ➥ 255.255.255.0
iv ➥ 255.255.254.0
Show Answer With Best Explanation
Answer: II
Explanation: We know, In a Class B network, the first 16 bits are the network part of the address. & remaining 16 bits indicate the host within the network.
Subnet mask: A subnet mask always consists of a series of contiguous 1 bits followed by a series of contiguous 0 bits.Where, • 1’s represent Network ID & Subnet ID • 0’s represent Host ID
Given that, Number of Subnet = 500 subnet So, Number of bits required to represent subnet = ceil value of(500) = 9bits
Number of Host per subnet = 100 subnet So, Number of bits required to represent subnet = ceil value of(100) = 7 bits
Now, We borrow 9bits of Subnet ID bits from Host ID part(16 bits is HID part in class B) to represent 500 subnet. Network ID bits = 16 bits Subnet ID bits = 9 bits Host ID bits = 16-9 = 7bits
Now its obvious, Number of 1’s in subnet mask = Network ID bits + Subnet ID bits = 16 + 9 = 25 Number of 0’s in subnet mask = Host ID bits = 7
Hence, Subnet Mask is 1111 1111 . 1111 1111 . 1111 1111 . 1000 0000 In decimal form it is represented as: 255 : 255 : 255 : 128
Q35➡ | NET June 2019 A fully connected network topology is a topology in which there is a direct link between all pairs of nodes. Given a fully connected network with n nodes, the number of direct links as a function of n can be expressed as
Q36➡ | NET June 2019 Which of the following statements is/are true with regard to various layers in the Internet stack? P: At the link layer, a packet of transmitted information is called a frame Q: At the network layer, a packet of transmitted information is called a segment
Q37➡ | NET December 2018 Consider ISO-OSI network architecture reference model. Session layer of this model offer Dialog control, token management and __ as services.
Q38➡ | NET December 2018 An internet service provider (ISP) has following chunk of CIDR-based IP addresses available with it: 245.248.128.0/20 . The ISP want to give half of this chunk of addresses to organization A and a quarter to Organization B while retaining the remaining with itself. Which of the following is a valid allocation of addresses to A and B?
i ➥ 245.248.132.0/22 and 245.248.132.0/21
ii ➥ 245.248.136.0/21 and 245.248.128.0/22
iii ➥ 245.248.136.0/24 and 245.248.132.0/21
iv ➥ 245.248.128.0/21 and 245.248.128.0/22
Show Answer With Best Explanation
Answer: II
Explanation:
According to given Option, valid allocation of addresses to A = 245.248.136.0/21 and valid allocation of addresses to B = 245.248.128.0/22
Q39➡ | NET December 2018 Which of the following statement/s is/are true? (i) Firewall can screen traffic going into or out of an organization. (ii) Virtual private networks cam simulate an old leased network to provide certain desirable properties. Choose the correct answer from the code given below:
Q40➡ | NET December 2018 Identify the correct sequence in which the following packets are transmitted on the network by a host when a browser requests a web page from a remote server, assuming that the host has been restarted.
Q41➡ | NET December 2018 Consider the following two statements: S1: TCP handles both congestion and flow control S2: UDP handles congestion but not flow control Which of the following option is correct with respect to the above statements (S1) and (S2)?
i ➥ Both S1 and S2 are correct
ii ➥ Neither S1 nor S2 is correct
iii ➥ S1 is not correct but S2 is correct
iv ➥ S1 is correct but S2 is not correct
Show Answer With Best Explanation
Answer: IV
Explanation: UDP Operation: • Connectionless Services • Unreliable Services • No flow Control • No Error Control Except Checksum • No Congestion Control Protocol • No retransmission • UDP is a message-oriented protocol.
TCP Operation: • Connection Oriented Services • reliable Services • flow Control • Error Control • Congestion Control Protocol • Retransmission • TCP is a byte-oriented protocol.
Statements S1: TCP handles both congestion and flow control(True) Statements S2: UDP handles congestion but not flow control(False)
Q42➡| NET December 2018 Match the following secret key algorithm (List 1) with the corresponding key lengths (List 2) and choose the correct answer from the code given below:
Explanation: IP Address: An IP address is a 32-bit number. The 32 bits are divided into four octets. an IP address is divided into Two parts named network id and host id. The first part (Network id)of an IP address identifies the network on which the host resides, while the second part(Host id) identifies the particular host on the given network.
Q44➡| NET December 2018 Which of the following statement/s is/are true ? (i) windows XP supports both peer-peer and client-server networks. (ii) Windows XP implements Transport protocols as drivers that can be loaded and uploaded from the system dynamically.
Q45➡| NET December 2018 The host is connected to a department network which is a part of a university network. The university network, in turn, is part of the internet. The largest network, in which the Ethernet address of the host is unique, is
Q46➡| NET December 2018 Suppose that everyone in a group of N people wants to communicate secretly with (N-1) other people using symmetric key cryptographic system. The communication between any two persons should not be decodable by the others in the group. The number of keys required in the system as a whole to satisfy the confidentiality requirement is
Q47➡| NET June 2018 A slotted ALOHA network transmits 200-bit frames using a shared channel with a 200 Kbps bandwidth. Find the throughput of the system, if the system (all stations put together) produces 250 frames per second:
i ➥ 49
ii ➥ 368
iii ➥ 149
iv ➥ 151
Show Answer With Best Explanation
Answer: I
Explanation: Given, Frame size = 200 bits Channel Bandwidth= 200 Kbps System Produces = 250 frame per second
Ask, Throughput of the system = ?
Formula, The Throughput of slotted ALOHA is S = G * e-G The maximum Throughput Smax = 0.368 (or 36.8%) when G =1 Where, G is the average number of frames produced by the system during one frame transmission time. The Frame Transmission time =
Calculation, The Frame Transmission time = = 10-3 second = 1 millisecond System Produces = 250 frame per second = (250 * 103 / 103) frame per second = (1/4) frame per millisecond so, The Load (G) = 1/4 frame
S = G * e-G = (1/4) * e-(1/4) = 0.195 (or 19.5%) {where, e = 2.71}
Throughput = 250 * 0.195 = 49 Frames Only 49 out of 259 frames will survive.
Q49➡| NET June 2018 The dotted-decimal notation of the following IPV4 address in binary notation is . 10000001 00001011 00001011 11101111
i ➥ 111.56.45.239
ii ➥ 129.11.10.238
iii ➥ 129.11.11.239
iv ➥ 111.56.11.239
Show Answer With Best Explanation
Answer: III
Explanation: Dotted Decimal Representation: An IP address is a 32-bit number written in dotted decimal notation, four 8-bit fields (octets) converted from binary to decimal numbers, separated by dots.
10000001 00001011 00001011 11101111
convert 8-bit binary to decimal & seperate them by dots
Q50➡| NET June 2018 Which of the following statements are true ? (I) Advanced Mobile Phone System (AMPS) is a second generation cellular phone system. (II) IS – 95 is a second generation cellular phone system based on CDMA and DSSS. (III) The Third generation cellular phone system will provide universal personnel communication.
Q52➡| NET June 2018 Which of the following statements are true ? (a) Three broad categories of Networks are (i) Circuit Switched Networks (ii) Packet Switched Networks (iii) Message Switched Networks (b) Circuit Switched Network resources need not be reserved during the set up phase. (c) In packet switching there is no resource allocation for packets. Code:
i ➥ (a) and (b) only
ii ➥ (b) and (c) only
iii ➥ (a) and (c) only
iv ➥ (a), (b) and (C)
Show Answer With Best Explanation
Answer: III
Explanation: Switching: In large networks, there can be multiple paths from sender to receiver. The switching technique will decide the best route for data transmission. Three broad categories of Networks are (i) Circuit Switched Networks (ii) Packet Switched Networks (iii) Message Switched Networks
Circuit Switched Networks • A dedicated path is establish between sender and receiver. • Resources need to be reserved during the set up phase.
Packet Switched Networks • Itis a switching technique in which the message is sent in one go, but it is divided into smaller pieces, and they are sent individually. • There are two approaches to Packet Switching: 1) Datagram Packet switching: • Resourse is reserved • Connection oriented
2) Virtual Circuit Switching • no Resourse is reserved • Connectionless
Message Switching • It is a switching technique in which a message is transferred as a complete unit and routed through intermediate nodes at which it is stored and forwarded. • In Message Switching technique, there is no establishment of a dedicated path between the sender and receiver. • Resources need not reserved during the set up phase.
Q54➡| NET June 2018 Decrypt the message “WTAAD” using the Caesar Cipher with key=15.
i ➥ LIPPS
ii ➥ HELLO
iii ➥ OLLEH
iv ➥ DAATW
Show Answer With Best Explanation
Answer: II
Explanation: Basic Concept A substitution cipher replaces one symbol with another. Substitution ciphers can be categorized as • Mono alphabetic • Polyalphabetic ciphers
Shift Cipher • The simplest monoalphabetic cipher is probably the shift cipher. • The shift cipher is sometimes referred to as the Caesar cipher. • The encryption algorithm is “shift key characters down,” with key equal to some number. The decryption algorithm is “shift key characters up.”
Calculation W = 23 -15 = 8 (h) T = 20 -15 =5 (e) A = 1 – 15 = -14 + 26 = 12 (l) {when get negative number then add 26 to wrap arround} A = 1 – 15 = -14 + 26 = 12 (l) D = 4 – 15 = -11 + 26 = 15 (o)
Q56➡| NET June 2018 Encrypt the Message “HELLO MY DEARZ” using Transposition Cipher with
i ➥ HLLEO YM AEDRZ
ii ➥ EHOLL ZYM RAED
iii ➥ ELHL MDOY AZER
iv ➥ ELHL DOMY ZAER
Show Answer With Best Explanation
Answer: III
Explanation: Given, PainText = HELLO MY DEARZ In encryption, we move the character at position 2 to position 1, the character at Position 4 to position 2, and so on.
Q57➡| NET November 2017 Paper-2 Which of the following devices takes data sent from one network device and forwards it to the destination node based on MAC address ?
= 10-3 second = 1 millisecond
second
second
Hz
