MCQOPTIONS
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MCQOPTIONS
This section includes 20 Mcqs, each offering curated multiple-choice questions to sharpen your Computer Networks knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Network Interface Card (NIC) has a unique six-byte permanent address as |
| A. | IP address |
| B. | MAC address |
| C. | DNS address |
| D. | Local address |
| Answer» C. DNS address | |
| 2. |
Protocols in which the sender sends one frame and then waits for an acknowledgement before proceeding for next frame are called as ________. |
| A. | Simplex protocols |
| B. | Unrestricted simplex protocols |
| C. | Simplex stop and wait protocols |
| D. | Restricted simplex protocols |
| Answer» D. Restricted simplex protocols | |
| 3. |
Consider the following statements regarding the slow start phase of the TCP congestioncontrol algorithm. Note that cwnd stands for the TCP congestion window and MSS denotesthe Maximum Segment Size.(i) The cwnd increases by 2 MSS on every successful acknowledgment.(ii) The cwnd approximately doubles on every successful acknowledgement.(iii) The cwnd increases by 1 MSS every round trip time.(iv) The cwnd approximately doubles every round trip time.Which one of the following is correct? |
| A. | Only (ii) and (iii) are true |
| B. | Only (i) and (iii) are true |
| C. | Only (iv) is true |
| D. | Only (i) and (iv) are true |
| Answer» D. Only (i) and (iv) are true | |
| 4. |
Given below are two statements:Statement I: The laws of nature put two fundamental limits on data rate of a channel. The H.Nyquist limit restricts the number of independent samples per second to twice the band-width in a Noiseless channel.Statement II: Shannon's major result about noised channel is that maximum data rate of a channel whose band width is H Hz, and whose signal-to-noise ratio is S/N is given by:Maximum number of bits/sec \(= H \;log_2 \left(1+\frac{S}{N}\right)\) is given by:In the light of the above statements. choose the correct answer from the options given below |
| A. | Both Statement I and Statement II are true |
| B. | Both Statement I and Statement II are false |
| C. | Statement I is correct but Statement II is false |
| D. | Statement I is incorrect but Statement II is true |
| Answer» B. Both Statement I and Statement II are false | |
| 5. |
A supernet has a first address of 205.16.32.0 and a supernet mask of 255.255.248.0. A router receives four packets with the following destination addresses. Which packet belongs to this supernet? |
| A. | 205.16.42.56 |
| B. | 205.17.32.76 |
| C. | 205.16.31.10 |
| D. | 205.16.39.44 |
| Answer» E. | |
| 6. |
Assume that source S and destination D are connected through two intermediate routers labeled R. Determine how many times each packet has to visit the network layer and the data link layer during a transmission from S to D. |
| A. | Network layer – 4 times and Data link layer – 4 times |
| B. | Network layer – 4 times and Data link layer – 3 times |
| C. | Network layer – 4 times and Data link layer – 6 times |
| D. | Network layer – 2 times and Data link layer – 6 times |
| Answer» D. Network layer – 2 times and Data link layer – 6 times | |
| 7. |
Firewall is a device that filters access to the protected network from the outside network. Firewalls 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 PortChoose the correct answer from the options given below: |
| A. | (A), (B) and (C) only |
| B. | (B) and (E) only |
| C. | (C) and (D) only |
| D. | (A), (B), (C), (D) and (E) only |
| Answer» E. | |
| 8. |
If a file consisting of 50,000 characters takes 40 seconds to send, then the data rate is ______ |
| A. | 1 kbps |
| B. | 1.25 kbps |
| C. | 2 kbps |
| D. | 10 kbps |
| Answer» E. | |
| 9. |
Assuming that for a given network layer implementation, connection establishment overhead is 100 bytes and disconnection overhead is 28 bytes. What would be the minimum size of the packet the transport layer neds to keep up, if wishes to implement a datagram service above the network layer and needs to keep overhead to a minimum of 12.5%. (Ignore transport layer overhead) |
| A. | 512 bytes |
| B. | 768 bytes |
| C. | 1152 bytes |
| D. | 1024 bytes |
| Answer» E. | |
| 10. |
Consider the following two statements.S1 : Destination MAC address of an ARP reply is a broadcast address.S2 : Destination MAC address of an ARP request is a broadcast address.Which one of the following choices is correct? |
| A. | S1 is tue and S2 is false. |
| B. | Both S1 and S2 are false. |
| C. | S1 is false and S2 is true. |
| D. | Both S1 and S2 are true. |
| Answer» D. Both S1 and S2 are true. | |
| 11. |
Post office protocol (POP) is a message access protocol which is used to extract message for client. 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 mail box after each retrival(C) In Delete mode, mail is deleted from mail box before each retrieval(D) In keep mode, mail is deleted before retrival(E) In keep mode, mail remains in mail box after retrivalChoose the correct answer from the options given below: |
| A. | (A) and (B) only |
| B. | (A), (D) and (E) only |
| C. | (A), (B), (C) and (D) only |
| D. | (A), (B) and (E) only |
| Answer» E. | |
| 12. |
An organization is granted the block 130.34.12.64 / 26. It needs to have four subnets. Which of the following is not an address of this organization? |
| A. | 130.34.12.124 |
| B. | 130.34.12.89 |
| C. | 130.34.12.70 |
| D. | 130.34.12.132 |
| Answer» E. | |
| 13. |
Assume that Source S and Destination D are connected through an intermediate router R. How many times a packet has to visit the network layer and data link layer during a transmission from S to D? |
| A. | Network layer – 4 times, Data link layer – 4 times |
| B. | Network layer – 4 times, Data link layer – 6 times |
| C. | Network layer – 2 times, Data link layer – 4 times |
| D. | Network layer – 3 times, Data link layer – 4 times |
| Answer» E. | |
| 14. |
Assume that the bandwidth for a TCP connection is 1048560 bits /sec. Let α be the value of RTT in milliseconds (rounded off to the nearest integer) after which the TCP window scale option is needed. Let β be the maximum possible window size with window scale option. Then the values of α and β are |
| A. | 63 milliseconds, 65535 x 214 |
| B. | 63 milliseconds, 65535 x 216 |
| C. | 500 milliseconds, 65535 x 214 |
| D. | 500 milliseconds, 65535 x 216 |
| Answer» D. 500 milliseconds, 65535 x 216 | |
| 15. |
Consider the following routing table at an IP router:Network No.Net MaskNext Hop128.96.170.0255.255.254.0Interface 0128.96.168.0255.255.254.0Interface 1128.96.166.0255.255.254.0R2128.96.164.0255.255.252.0R30.0.0.0DefaultR4For each IP address in Group I identify the correct choice of the next hop from Group II using the entries from the routing table above.Group I Group IIi) 128.96.171.92 a) Interface 0ii) 128.96.167.151 b) Interface 1iii) 128.96.163.151 c) R2iv) 128.96.165.121 d) R3 e) R4 |
| A. | i – a, ii – c, iii – e, iv – d |
| B. | i – a, ii – d, iii – b, iv – e |
| C. | i – b, ii – c, iii – d, iv – e |
| D. | i – b, ii – c, iii – e, iv – d |
| Answer» B. i – a, ii – d, iii – b, iv – e | |
| 16. |
A message consisting of 2400 bits is to be passed over the Internet. The message is passed to the transport layer which appends a 150-bit header, followed by the network layer which uses a 120-bit header. Network layer packets are transmitted via two networks, each of which uses a 26-bit header. The destination network only accepts up to 900 bits long. The number of bits, including headers delivered to the destination network, is |
| A. | 2706 bits |
| B. | 2634 bits |
| C. | 2554 bits |
| D. | 2476 bits |
| Answer» B. 2634 bits | |
| 17. |
An analog signal carries 4 bits in each signal unit. If 1000 signal units are sent per second, then baud rate and bit rate of the signal are ________ and __________. |
| A. | 1000 bauds / sec, 500 bps |
| B. | 2000 bauds / sec, 1000 bps |
| C. | 4000 bauds / sec, 1000 bps |
| D. | 1000 bauds / sec, 4000 bps |
| Answer» E. | |
| 18. |
In a communication network. 4 T1 streams are multiplexed to form 1 T2 stream and 7 T1 streams are multiplexed to form 1 T3 stream. Further 6 T3 streams are multiplexed to form 1 T4 stream. If each T1 stream is of 1.544 Mbps, the data rate of 1 T4 stream should be |
| A. | 211.8 Mbps |
| B. | 232.6 Mbps |
| C. | 243.4 Mbps |
| D. | 274.2 Mbps |
| Answer» E. | |
| 19. |
On a TCP connection, current congestion window size is Congestion Window = 4 KB. The window size advertised by the received is Advertise Window = 6 KB. The last byte sent by the sender is Last Byte Sent = 10240 and the last byte acknowledged by the receiver is Last Byte Acked = 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 | |
| 20. |
Generally, TCP is reliable and UDP is not reliable. DNS which has to be reliable uses UDP because |
| A. | UDP is slower |
| B. | DNS servers has to keep connections |
| C. | DNS requests are generally very small and fit well within UDP segments |
| D. | None of these |
| Answer» D. None of these | |