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MCQOPTIONS
This section includes 406 Mcqs, each offering curated multiple-choice questions to sharpen your Graduate Aptitude Test (GATE) knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
In what way does a firewall increase the securities of a VPN? |
| A. | Configured to allow certain ports to access the VPN |
| B. | Physically protects the network from catching fire |
| C. | Restricts the use of specific application software on the network |
| D. | Limits the speed in which transmission of data is carried out |
| Answer» D. Limits the speed in which transmission of data is carried out | |
| 52. |
A channel has a bit rate of 4 kbps and one-way propagation delay of 20 ms. The channel uses stop and wait protocol. The transmission time of the acknowledgement frame is negligible. To get a channel efficiency of at least 50%, the minimum frame size should be |
| A. | 80 bytes |
| B. | 80 bits |
| C. | 160 bytes |
| D. | 160 bits |
| Answer» E. | |
| 53. |
In an Ethernet local area network, which one of the following statements is TRUE ? |
| A. | A station stops to sense the channel once it starts transmitting a frame |
| B. | The purpose of the jamming signal is to pad the frames that are smaller than the minimum frame size |
| C. | A station continues to transmit the packet even after the collision is detected |
| D. | The exponential backoff mechanism reduces the probability of collision on retransmissions |
| Answer» E. | |
| 54. |
A and B are the only two stations on an Ethernet. Each has a steady queue of frames to send. Both A and B attempt to transmit a frame, collide, and A wins the first backoff race. At the end of this successful transmission by A, both A and B attempt to transmit and collide. The probability that A wins the second backoff race is: |
| A. | 0.5 |
| B. | 0.625 |
| C. | 0.75 |
| D. | 1.0 |
| Answer» C. 0.75 | |
| 55. |
Station A uses 32 byte packets to transmit messages to Station B using a sliding window protocol. The round trip delay between A and B is 80 milliseconds and the bottleneck bandwidth on the path between A and B is 128 kbps. What is the optimal window size that A should use? |
| A. | 20 |
| B. | 40 |
| C. | 160 |
| D. | 320 |
| Answer» C. 160 | |
| 56. |
How many 8-bit characters can be transmitted per second over a 9600 baud serial communication link using asynchronous mode of transmission with one start bit, eight data bits, two stop bits, and one parity bit ? |
| A. | 600 |
| B. | 800 |
| C. | 876 |
| D. | 1200 |
| Answer» C. 876 | |
| 57. |
Suppose that the stop-and-wait protocol is used on a link with a bit rate of 64 kilobits per second and 20 milliseconds propagation delay. Assume that the transmission time for the acknowledgment and the processing time at nodes are negligible. Then the minimum frame size in bytes to achieve a link utilization of at least 50% is _________. |
| A. | 160 |
| B. | 320 |
| C. | 640 |
| D. | 220 |
| Answer» C. 640 | |
| 58. |
In serial data transmission, every byte of data is padded with a ‘0’ in the beginning and one or two ‘I’ s at the end of byte because |
| A. | Receiver is to be synchronized for byte reception |
| B. | Receiver recovers lost ‘0’ and ‘1’s from these padded bits |
| C. | Padded bits are useful in parity computation |
| D. | None of these |
| Answer» B. Receiver recovers lost ‘0’ and ‘1’s from these padded bits | |
| 59. |
Consider a LAN with four nodes S1, S2, S3 and S4. Time is divided into fixed-size slots, and a node can begin its transmission only at the beginning of a slot. A collision is said to have occurred if more than one node transmit in the same slot. The probabilities of generation of a frame in a time slot by S1, S2, S3 and S4 are 0.1, 0.2, 0.3 and 0.4, respectively. The probability of sending a frame in the first slot without any collision by any of these four stations is _________. |
| A. | 0.462 |
| B. | 0.711 |
| C. | 0.5 |
| D. | 0.652 |
| Answer» B. 0.711 | |
| 60. |
A 1Mbps satellite link connects two ground stations. The altitude of the satellite is 36,504 km and speed of the signal is 3 × 10^8 m/s. What should be the packet size for a channel utilization of 25% for a satellite link using go-back-127 sliding window protocol? Assume that the acknowledgment packets are negligible in size and that there are no errors during communication. |
| A. | 120 bytes |
| B. | 60 bytes |
| C. | 240 bytes |
| D. | 90 bytes |
| Answer» B. 60 bytes | |
| 61. |
Host A is sending data to host B over a full duplex link. A and B are using the sliding window protocol for flow control. The send and receive window sizes are 5 packets each. Data packets (sent only from A to B) are all 1000 bytes long and the transmission time for such a packet is 50 µs. Acknowledgement packets (sent only from B to A) are very small and require negligible transmission time. The propagation delay over the link is 200 us. What is the maximum achievable throughput in this communication? |
| A. | 7.69 × 10^6 bytes per second |
| B. | 11.11 × 10^6 bytes per second |
| C. | 12.33 × 10^6 bytes per second |
| D. | 15.00 × 10^6 bytes per second |
| Answer» C. 12.33 × 10^6 bytes per second | |
| 62. |
The minimum frame size required for a CSMA/CD based computer network running at 1 Gbps on a 200m cable with a link speed of 2 × 10^8m/s is |
| A. | 125 bytes |
| B. | 250 bytes |
| C. | 500 bytes |
| D. | None of these |
| Answer» C. 500 bytes | |
| 63. |
Consider a source computer(S) transmitting a file of size 106 bits to a destination computer(D)over a network of two routers (R1 and R2) and three links(L1, L2, and L3). L1connects S to R1; L2 connects R1 to R2; and L3 connects R2 to D.Let each link be of length 100 km. Assume signals travel over each link at a speed of 108 meters per second.Assume that the link bandwidth on each link is 1Mbps. Let the file be broken down into 1000 packets each of size 1000 bits. Find the total sum of transmission and propagation delays in transmitting the file from S to D? |
| A. | 1005 ms |
| B. | 1010 ms |
| C. | 3000 ms |
| D. | 3003 ms |
| Answer» B. 1010 ms | |
| 64. |
Station A needs to send a message consisting of 9 packets to Station B using a sliding window (window size 3) and go-back-n error control strategy. All packets are ready and immediately available for transmission. If every 5th packet that A transmits gets lost (but no acks from B ever get lost), then what is the number of packets that A will transmit for sending the message to B? |
| A. | 12 |
| B. | 14 |
| C. | 16 |
| D. | 18 |
| Answer» D. 18 | |
| 65. |
Consider the following three statements about link state and distance vector routing protocols, for a large network with 500 network nodes and 4000 links.[S1] The computational overhead in link state protocols is higher than in distance vector protocols.[S2] A distance vector protocol (with split horizon) avoids persistent routing loops, but not a link state protocol.[S3] After a topology change, a link state protocol will converge faster than a distance vector protocol.Which one of the following is correct about S1, S2, and S3 ? |
| A. | S1, S2, and S3 are all true |
| B. | S1, S2, and S3 are all false |
| C. | S1 and S2 are true, but S3 is false |
| D. | S1 and S3 are true, but S2 is false |
| Answer» E. | |
| 66. |
Assume that "host1.mydomain.dom" has an IP address of 145.128.16.8. Which of the following options would be most appropriate as a subsequence of steps in performing the reverse lookup of 145.128.16.8? In the following options "NS" is an abbreviation of "nameserver". |
| A. | Query a NS for the root domain and then NS for the "dom" domains |
| B. | Directly query a NS for "dom" and then a NS for "mydomain.dom" domains |
| C. | Query a NS for in-addr.arpa and then a NS for 128.145.in-addr.arpa domains |
| D. | Directly query a NS for 145.in-addr.arpa and then a NS for 128.145.in-addr.arpa domains |
| Answer» D. Directly query a NS for 145.in-addr.arpa and then a NS for 128.145.in-addr.arpa domains | |
| 67. |
Count to infinity is a problem associated with |
| A. | link state routing protocol |
| B. | distance vector routing protocol |
| C. | DNS while resolving host name |
| D. | TCP for congestion control |
| Answer» C. DNS while resolving host name | |
| 68. |
Traceroute reports a possible route that is taken by packets moving from some host A to some other host B. Which of the following options represents the technique used by traceroute to identify these hosts |
| A. | By progressively querying routers about the next router on the path to B using ICMP packets, starting with the first router |
| B. | By requiring each router to append the address to the ICMP packet as it is forwarded to B. The list of all routers en-route to B is returned by B in an ICMP reply packet |
| C. | By ensuring that an ICMP reply packet is returned to A by each router en-route to B, in the ascending order of their hop distance from A |
| D. | By locally computing the shortest path from A to B |
| Answer» B. By requiring each router to append the address to the ICMP packet as it is forwarded to B. The list of all routers en-route to B is returned by B in an ICMP reply packet | |
| 69. |
Host A (on TCP/IP v4 network A) sends an IP datagram D to host B (also on TCP/IP v4 network B). Assume that no error occurred during the transmission of D. When D reaches B, which of the following IP header field(s) may be different from that of the original datagram D?(i) TTL (ii) Checksum (iii) Fragment Offset |
| A. | (i) only |
| B. | (i) and (ii) only |
| C. | (ii) and (iii) only |
| D. | (i), (ii) and (iii) |
| Answer» E. | |
| 70. |
In a packet switching network, packets are routed from source to destination along a single path having two intermediate nodes. If the message size is 24 bytes and each packet contains a header of 3 bytes, then the optimum packet size is: |
| A. | 4 |
| B. | 6 |
| C. | 7 |
| D. | 9 |
| Answer» E. | |
| 71. |
A company has a class C network address of 204.204.204.0. It wishes to have three subnets, one with 100 hosts and two with 50 hosts each. Which one of the following options represents a feasible set of subnet address/subnet mask pairs? |
| A. | 204.204.204.128/255.255.255.192 204.204.204.0/255.255.255.128 204.204.204.64/255.255.255.128 |
| B. | 204.204.204.0/255.255.255.192 204.204.204.192/255.255.255.128 204.204.204.64/255.255.255.128 |
| C. | 204.204.204.128/255.255.255.128 204.204.204.192/255.255.255.192 204.204.204.224/255.255.255.192 |
| D. | 204.204.204.128/255.255.255.128 204.204.204.64/255.255.255.192 204.204.204.0/255.255.255.192 |
| Answer» E. | |
| 72. |
Two popular routing algorithms are Distance Vector(DV) and Link State (LS) routing. Which of the following are true?(S1) Count to infinity is a problem only with DV and not LS routing(S2) In LS, the shortest path algorithm is run only at one node(S3) In DV, the shortest path algorithm is run only at one node(S4) DV requires lesser number of network messages than LS |
| A. | S1, S2 and S4 only |
| B. | S1, S3 and S4 only |
| C. | S2 and S3 only |
| D. | S1 and S4 only |
| Answer» E. | |
| 73. |
Suppose that the maximum transmit window size for a TCP connection is 12000 bytes. Each packet consists of 2000 bytes. At some point of time, the connection is in slow-start phase with a current transmit window of 4000 bytes. Subsequently, the transmitter receives two acknowledgements. Assume that no packets are lost and there are no time-outs. What is the maximum possible value of the current transmit window? |
| A. | 4000 bytes |
| B. | 8000 bytes |
| C. | 10000 bytes |
| D. | 12000 bytes |
| Answer» C. 10000 bytes | |
| 74. |
Consider a bandwidth of line 200mbps and sequence number field is 48-bits. Find out the wrap-around time of sequence numbers. |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» D. D | |
| 75. |
Let the value of the RTT(Round-Trip-Time)is to be measure (d). The value of the previous RTT be 350μs. Let the value of α be 90% the new RTT, hence the retransmission time is ______ .(Assume it takes a segment at this moment to be acknowledged in 90μs) |
| A. | 396, 796 |
| B. | 348, 696 |
| C. | 321, 644 |
| D. | 324, 648 |
| Answer» E. | |
| 76. |
Choose the false one. |
| A. | Diffie – Hellman protocol is a symmetric key protocol |
| B. | In RSA, both keys are private |
| C. | DES is a block clipher algorithm |
| D. | Vigenere clipher is poly-alphabetic in nature |
| Answer» C. DES is a block clipher algorithm | |
| 77. |
Which of the following assertions is FALSE about the Internet Protocol (IP) ? |
| A. | It is possible for a computer to have multiple IP addresses |
| B. | IP packets from the same source to the same destination can take different routes in the network |
| C. | IP ensures that a packet is discarded if it is unable to reach its destination within a given number of hops |
| D. | The packet source cannot set the route of an outgoing packets; the route is determined only by the routing tables in the routers on the way |
| Answer» E. | |
| 78. |
In TCP, a unique sequence number is assigned to each |
| A. | byte |
| B. | word |
| C. | segment |
| D. | message |
| Answer» B. word | |
| 79. |
Which of the following functionalities must be implemented by a transport protocol over and above the network protocol ? |
| A. | Recovery from packet losses |
| B. | Detection of duplicate packets |
| C. | Packet delivery in the correct order |
| D. | End to end connectivity |
| Answer» E. | |
| 80. |
Packets of the same session may be routed through different paths in |
| A. | TCP, but not UDP |
| B. | TCP and UDP |
| C. | UDP, but not TCP |
| D. | Neither TCP, nor UDP |
| Answer» C. UDP, but not TCP | |
| 81. |
In class C , if subnet mask is 255.255.255.224, then calculates number of subnet? |
| A. | 6 |
| B. | 8 |
| C. | 4 |
| D. | None of the Above |
| Answer» B. 8 | |
| 82. |
Which one of the following statements is FALSE ? |
| A. | Packet switching leads to better utilization of bandwidth resources than circuit switching |
| B. | Packet switching results in less variation in delay than circuit switching |
| C. | Packet switching requires more per packet processing than circuit switching |
| D. | Packet switching can lead to reordering unlike in circuit switching |
| Answer» C. Packet switching requires more per packet processing than circuit switching | |
| 83. |
A 2 km long broadcast LAN has 10^7 bps bandwidth and uses CSMA/CD. The signal travels along the wire at 2 × 108 m/s. What is the minimum packet size that can be used on this network? |
| A. | 50 bytes |
| B. | 100 bytes |
| C. | 200 bytes |
| D. | None of these |
| Answer» E. | |
| 84. |
An IP datagram of size 1000 bytes arrives at a router. The router has to forward this packet on a link whose MTU (maximum transmission unit) is 100 bytes. Assume that the size of the IP header is 20 bytes. The number of fragments that the IP datagram will be divided into for transmission is : |
| A. | 10 |
| B. | 50 |
| C. | 12 |
| D. | 13 |
| Answer» E. | |
| 85. |
A network with CSMA/CD protocol in the MAC layer is running at 1 Gbps over a 1 km cable with no repeaters. The signal speed in the cable is 2 x 108 m/sec. The minimum frame size for this network should be |
| A. | 10000 bits |
| B. | 10000 bytes |
| C. | 5000 bits |
| D. | 5000 bytes |
| Answer» B. 10000 bytes | |
| 86. |
The routing table of a router is shown below: Destination Sub net mask Interface 128.75.43.0 255.255.255.0 Eth0 128.75.43.0 255.255.255.128 Eth1 192.12.17.5 255.255.255.255 Eth3 default Eth2On which interfaces will the router forward packets addressed to destinations 128.75.43.16 and 192.12.17.10 respectively? |
| A. | Eth1 and Eth2 |
| B. | Eth0 and Eth2 |
| C. | Eth0 and Eth3 |
| D. | Eth1 and Eth3 |
| Answer» B. Eth0 and Eth2 | |
| 87. |
Which one is not a method of HTTP? |
| A. | PATCH |
| B. | OPTION |
| C. | UNLINK |
| D. | CUT |
| Answer» E. | |
| 88. |
Which of the following statements is FALSE regarding a bridge? |
| A. | Bridge is a layer 2 device |
| B. | Bridge reduces collision domain |
| C. | Bridge is used to connect two or more LAN segments |
| D. | Bridge reduces broadcast domain |
| Answer» E. | |
| 89. |
Which of the following is NOT true with respect to a transparent bridge and a router? |
| A. | Both bridge and router selectively forward data packets |
| B. | A bridge uses IP addresses while a router uses MAC addresses |
| C. | A bridge builds up its routing table by inspecting incoming packets |
| D. | A router can connect between a LAN and a WAN |
| Answer» C. A bridge builds up its routing table by inspecting incoming packets | |
| 90. |
Which of the following statements is TRUE about CSMA/CD ? |
| A. | IEEE 802.11 wireless LAN runs CSMA/CD protocol |
| B. | Ethernet is not based on CSMA/CD protocol |
| C. | CSMA/CD is not suitable for a high propagation delay network like satellite network |
| D. | There is no contention in a CSMA/CD network |
| Answer» D. There is no contention in a CSMA/CD network | |
| 91. |
Routers forward a packet using forwarding table entries. The network address of incoming packet may match multiple entries. How routers resolve this? |
| A. | Forward it the the router whose entry matches with the longest prefix of incoming packet |
| B. | Forward the packet to all routers whose network addresses match |
| C. | Discard the packet |
| D. | Forward it the the router whose entry matches with the longest suffix of incoming packet |
| Answer» B. Forward the packet to all routers whose network addresses match | |
| 92. |
Which protocol will be used to automate the IP configuration mechanism which includes IP address, subnet mask, default gateway, and DNS information? |
| A. | SMTP |
| B. | DHCP |
| C. | ARP |
| D. | TCP/IP |
| Answer» C. ARP | |
| 93. |
Consider a network connecting two systems located 8000 kilometers apart. The bandwidth of the network is 500 × 10^6 bits per second. The propagation speed of the media is 4 × 10^6 meters per second. It is needed to design a Go-Back-N sliding window protocol for this network. The average packet size is 10^7 bits. The network is to be used to its full capacity. Assume that processing delays at nodes are negligible. Then, the minimum size in bits of he sequence number field has to be ________. |
| A. | 2 |
| B. | 4 |
| C. | 8 |
| D. | 16 |
| Answer» D. 16 | |
| 94. |
Consider the following message M = 1010001101. The cyclic redundancy check (CRC) for this message using the divisor polynomial x^5 + x^4 + x^2 + 1 is : |
| A. | 01110 |
| B. | 01011 |
| C. | 10101 |
| D. | 10110 |
| Answer» B. 01011 | |
| 95. |
The address resolution protocol (ARP) is used for |
| A. | Finding the IP address from the DNS |
| B. | Finding the IP address of the default gateway |
| C. | Finding the IP address that corresponds to a MAC address |
| D. | Finding the MAC address that corresponds to an IP address |
| Answer» E. | |
| 96. |
Identify the correct order in which the following actions take place in an interaction between a web browser and a web server.1. The web browser requests a webpage using HTTP.2. The web browser establishes a TCP connection with the web server.3. The web server sends the requested webpage using HTTP.4. The web browser resolves the domain name using DNS. |
| A. | 4,2,1,3 |
| B. | 1,2,3,4 |
| C. | 4,1,2,3 |
| D. | 2,4,1,3 |
| Answer» B. 1,2,3,4 | |
| 97. |
Consider different activities related to email.m1: Send an email from a mail client to a mail serverm2: Download an email from mailbox server to a mail clientm3: Checking email in a web browserWhich is the application level protocol used in each activity? |
| A. | ml: HTTP m2: SMTP m3: POP |
| B. | ml: SMTP m2: FTP m3: HTTP |
| C. | ml: SMTP m2: POP m3: HTTP |
| D. | ml: POP m2: SMTP m3: IMAP |
| Answer» D. ml: POP m2: SMTP m3: IMAP | |
| 98. |
Consider a TCP connection in a state where there are no outstanding ACKs. The sender sends two segments back to back. The sequence numbers of the first and second segments are 230 and 290 respectively. The first segment was lost, but the second segment was received correctly by the receiver. Let X be the amount of data carried in the first segment (in bytes), and Y be the ACK number sent by the receiver. The values of X and Y (in that order) are |
| A. | 60 and 290 |
| B. | 230 and 291 |
| C. | 60 and 231 |
| D. | 60 and 230 |
| Answer» E. | |
| 99. |
On a TCP connection, current congestion window size is Congestion Window = 4 KB. The window size advertised by the receiver is Advertise Window = 6 KB. The last byte sent by the sender is LastByteSent = 10240 and the last byte acknowledged by the receiver is LastByteAcked = 8192. The current window size at the sender is |
| A. | 2048 bytes |
| B. | 4096 bytes |
| C. | 6144 bytes |
| D. | 8192 bytes |
| Answer» C. 6144 bytes | |
| 100. |
For a host machine that uses the token bucket algorithm for congestion control, the token bucket has a capacity of 1 megabyte and the maximum output rate is 20 megabytes per second. Tokens arrive at a rate to sustain output at a rate of 10 megabytes per second. The token bucket is currently full and the machine needs to send 12 megabytes of data. The minimum time required to transmit the data is _________________ seconds. |
| A. | 1.1 |
| B. | 0.1 |
| C. | 2.1 |
| D. | 2.0 |
| Answer» B. 0.1 | |