Data Communication MCQs with Answers
Practice important Data Communication MCQs with answers and explanations.
Chapter: 169
Q2501:
What is the goal of the random delay in the ALOHA retransmission step?
A. Reduce congestion
B. Increase energy efficiency
C. Enhance synchronization
D. Speed up the process
Correct Answer:
A
Chapter: 169
Q2502:
What type of acknowledgment does ALOHA depend on?
A. Synchronous
B. Asynchronous
C. Explicit Implicit
Correct Answer:
C
Chapter: 169
Q2503:
Which of the following is NOT a step in the pure ALOHA procedure?
A. Send data
B. Wait for acknowledgment
C. Check if channel is idle
D. Resend if collision
Correct Answer:
C
Chapter: 169
Q2504:
Fill in the blank: The efficiency of pure ALOHA decreases when the _______ increases.
A. number of stations
B. number of channels
C. delay in acknowledgment
D. amount of memory used
Correct Answer:
A
Chapter: 170
Q2505:
What is the main purpose of dividing time into slots in Slotted ALOHA?
A. To avoid retransmissions
B. To eliminate data collisions
C. To increase efficiency over pure ALOHA
D. To reduce signal strength
Correct Answer:
C
Chapter: 170
Q2506:
In Slotted ALOHA, when is a station allowed to send data?
A. Anytime it has data to send
B. Only after receiving permission
C. At the beginning of a time slot
D. After detecting a collision
Correct Answer:
C
Chapter: 170
Q2507:
Fill in the blank: Slotted ALOHA was invented to improve the efficiency of _______.
A. CSMA
B. pure ALOHA
C. TDMA
D. FDMA
Correct Answer:
B
Chapter: 170
Q2508:
What happens if a station misses its designated time slot in Slotted ALOHA?
A. It sends immediately
B. It aborts transmission
C. It waits for the next available slot
D. It switches protocol
Correct Answer:
C
Chapter: 170
Q2509:
Fill in the blank: The vulnerable time in Slotted ALOHA is reduced to _______.
A. 2 x Tfr
B. 1 x Tfr
C. 0.5 x Tfr
D. 4 x Tfr
Correct Answer:
B
Chapter: 170
Q2510:
What does "Tfr" represent in Slotted ALOHA?
A. Time frame
B. Transmission frame
C. Transfer rate
D. Timeout frame
Correct Answer:
B
Chapter: 170
Q2511:
Which of the following best describes a key difference between Slotted and Pure ALOHA?
A. Time slot alignment
B. Random access delay
C. Carrier sensing
D. Time division multiplexing
Correct Answer:
A
Chapter: 170
Q2512:
Fill in the blank: In Slotted ALOHA, all stations are synchronized to start transmission _______.
A. at a random time
B. at different intervals
C. at the start of the slot
D. at the end of the slot
Correct Answer:
C
Chapter: 170
Q2513:
What is the benefit of reducing the vulnerable time to Tfr in Slotted ALOHA?
A. Lower bandwidth
B. Improved signal strength
C. Increased throughput
D. Lower energy consumption
Correct Answer:
C
Chapter: 170
Q2514:
In Slotted ALOHA, if two stations transmit in the same slot, what occurs?
A. One frame succeeds
B. Both frames are received
C. Frames collide and are lost
D. They merge into one frame
Correct Answer:
C
Chapter: 170
Q2515:
What is the maximum efficiency of Slotted ALOHA under ideal conditions?
A. 0.184
B. 0.368
C. 0.5
D. 1
Correct Answer:
B
Chapter: 170
Q2516:
Fill in the blank: Compared to Pure ALOHA, Slotted ALOHA _______ collision chances.
A. increases
B. reduces
C. eliminates
D. ignores
Correct Answer:
B
Chapter: 170
Q2517:
Which of the following is NOT a requirement of Slotted ALOHA?
A. Synchronized clocks
B. Time-slot allocation
C. Carrier sensing
D. Fixed transmission slots
Correct Answer:
C
Chapter: 170
Q2518:
What is a major limitation of Slotted ALOHA?
A. High synchronization overhead
B. Complex coding scheme
C. Fixed bandwidth
D. Multiple data channels
Correct Answer:
A
Chapter: 170
Q2519:
Fill in the blank: In Slotted ALOHA, collisions occur only when two stations transmit _______.
A. simultaneously
B. in consecutive slots
C. in idle time
D. after ACK
Correct Answer:
A
Chapter: 170
Q2520:
What feature allows Slotted ALOHA to outperform Pure ALOHA in terms of efficiency?
A. Carrier sensing
B. Time-slot alignment
C. Random backoff
D. Data encryption
Correct Answer:
B