Digital Communications Multiple Choice Questions on “Multiple access techniques for LAN and access algorithms”.
1. A local area network can be used to interconnect
A. Computers
B. Terminals
C. Printers
D. All of the mentioned
Answer: D
Clarification: A local area network can be used to interconnect computers, terminals, printers and so on located within a building or a small set of buildings.
2. LAN uses _________ cables.
A. Low bandwidth
B. High bandwidth
C. Low & High bandwidth
D. None of the mentioned
Answer: B
Clarification: Local area network uses high bandwidth cables for designing.
3. The maximum packet size of Ethernet is
A. 1426 bytes
B. 1526 bytes
C. 1256 bytes
D. 1626 bytes
Answer: B
Clarification: The maximum packet size of Ethernet is 1526 bytes where a byte is 8 bits.
4. The minimum packet size of Ethernet is
A. 81 bytes
B. 75 bytes
C. 72 bytes
D. 64 bytes
Answer: C
Clarification: The minimum packet size is 72 bytes, consisting of 8 byte preamble, 14 byte header, 46 byte data, 4 byte parity.
5. The interface between the ring and the stations are passive.
A. True
B. False
Answer: B
Clarification: The interface between the rings and the stations are active rather than passive.
6. Bit stuffing is done by inserting _____, after ____ consecutive ones.
A. Zero, seven
B. Zero, five
C. One, seven
D. One, five
Answer: A
Clarification: Bit stuffing is done by inserting a zero in the data stream after seven consecutive ones.
7. As channel capacity increases, channel throughput
A. Increases
B. Decreases
C. Remains the same
D. None of the mentioned
Answer: A
Clarification: As channel capacity R increases, the channel throughput should also increase.
8. In Aloha technique, the re-transmission takes place immediately.
A. True
B. False
Answer: B
Clarification: In Aloha technique if the negative acknowledgment is received, the re-transmission is done after a random delay so that it doesn’t collide again.
9. In which technique, packet size are constant?
A. Pure Aloha
B. Slotted Aloha
C. Pure & Slotted Aloha
D. None of the mentioned
Answer: A
Clarification: The Pure Aloha technique has constant packet lengths.
10. For a throughput of value less than 0.20, which has less average delay?
A. S-ALOHA
B. Pure ALOHA
C. R-ALOHA
D. None of the mentioned
Answer: A
Clarification: For a throughput value of less than 0.20, S-ALOHA has less average delay than R-ALOHA.
11. For a throughput value of 0.20 to 0.67, which has less average delay?
A. S-ALOHA
B. Pure ALOHA
C. R-ALOHA
D. None of the mentioned
Answer: C
Clarification: For throughput value of 0.20 to 0.67, it is clear that R-ALOHA is superior and has less average delay than S-ALOHA.
12. Binary tree search is used for
A. Multiple users
B. Single users
C. Single & Multiple users
D. None of the mentioned
Answer: A
Clarification: Binary tree search is used for rapid polling of user population and it is used for multiple users.
13. Which method is better suited for large population?
A. Straight polling
B. Binary tree search
C. Straight polling & Binary tree search
D. None of the mentioned
Answer: B
Clarification: Binary tree search is more efficient method than straight polling in case of a large population.
14. For a higher throughput value which method works efficiently?
A. S-ALOHA
B. Pure ALOHA
C. R-ALOHA
D. None of the mentioned
Answer: C
Clarification: At lower throughput values, S-ALOHA works better and for higher throughput values R-ALOHA works better.