CS6250 – COMPUTER NETWORKS
EXAM 2
🔥 100 MCQs WITH EXPLANATIONS 2026/2027
🔹 TRANSPORT LAYER
1. Which protocol provides reliable, ordered data delivery?
A. UDP
B. IP
C. TCP
D. ARP
✅ Answer: C (TCP)
Explanation:
TCP ensures:
Data arrives in order
Lost packets are retransmitted
Uses acknowledgments (ACKs)
UDP does none of these—so TCP is used where reliability matters (e.g., file transfer).
2. Which feature is NOT part of TCP?
A. Flow control
B. Congestion control
C. Error detection
D. Broadcast delivery
✅ Answer: D
Explanation:
TCP is unicast, meaning one-to-one communication.
Broadcast is handled at lower layers (Data Link/Network), not TCP.
3. UDP is preferred over TCP when:
,A. Reliability is critical
B. Speed is more important than accuracy
C. Data must be ordered
D. Data must be acknowledged
✅ Answer: B
Explanation:
UDP skips:
Error recovery
Acknowledgments
So it's faster and lightweight, ideal for:
Streaming
Online gaming
4. What does the TCP 3-way handshake establish?
A. Encryption
B. Routing path
C. Connection reliability parameters
D. IP addressing
✅ Answer: C
Explanation:
The handshake synchronizes:
Sequence numbers
Acknowledgment numbers
This ensures both sides are ready for reliable communication.
5. What is the main purpose of flow control?
A. Increase bandwidth
B. Prevent sender from overwhelming receiver
C. Reduce latency
D. Encrypt data
✅ Answer: B
Explanation:
Flow control ensures:
Sender sends data at a rate the receiver can handle
, Uses sliding window mechanism
🔹 CONGESTION CONTROL
6. What does TCP Slow Start do?
A. Reduces bandwidth
B. Gradually increases transmission rate
C. Stops transmission
D. Encrypts packets
✅ Answer: B
Explanation:
TCP starts with a small window size and:
Doubles it each round
Avoids sudden congestion in the network
7. What triggers Fast Retransmit?
A. Timeout
B. Duplicate ACKs
C. Packet size increase
D. Routing failure
✅ Answer: B
Explanation:
When TCP receives 3 duplicate ACKs, it assumes:
A packet is lost
Retransmits immediately (without waiting for timeout)
8. AIMD stands for:
A. Additive Increase Multiplicative Decrease
B. Automatic Internet Message Delivery
C. Advanced IP Management Design
D. Adaptive Interface Model Design
✅ Answer: A
EXAM 2
🔥 100 MCQs WITH EXPLANATIONS 2026/2027
🔹 TRANSPORT LAYER
1. Which protocol provides reliable, ordered data delivery?
A. UDP
B. IP
C. TCP
D. ARP
✅ Answer: C (TCP)
Explanation:
TCP ensures:
Data arrives in order
Lost packets are retransmitted
Uses acknowledgments (ACKs)
UDP does none of these—so TCP is used where reliability matters (e.g., file transfer).
2. Which feature is NOT part of TCP?
A. Flow control
B. Congestion control
C. Error detection
D. Broadcast delivery
✅ Answer: D
Explanation:
TCP is unicast, meaning one-to-one communication.
Broadcast is handled at lower layers (Data Link/Network), not TCP.
3. UDP is preferred over TCP when:
,A. Reliability is critical
B. Speed is more important than accuracy
C. Data must be ordered
D. Data must be acknowledged
✅ Answer: B
Explanation:
UDP skips:
Error recovery
Acknowledgments
So it's faster and lightweight, ideal for:
Streaming
Online gaming
4. What does the TCP 3-way handshake establish?
A. Encryption
B. Routing path
C. Connection reliability parameters
D. IP addressing
✅ Answer: C
Explanation:
The handshake synchronizes:
Sequence numbers
Acknowledgment numbers
This ensures both sides are ready for reliable communication.
5. What is the main purpose of flow control?
A. Increase bandwidth
B. Prevent sender from overwhelming receiver
C. Reduce latency
D. Encrypt data
✅ Answer: B
Explanation:
Flow control ensures:
Sender sends data at a rate the receiver can handle
, Uses sliding window mechanism
🔹 CONGESTION CONTROL
6. What does TCP Slow Start do?
A. Reduces bandwidth
B. Gradually increases transmission rate
C. Stops transmission
D. Encrypts packets
✅ Answer: B
Explanation:
TCP starts with a small window size and:
Doubles it each round
Avoids sudden congestion in the network
7. What triggers Fast Retransmit?
A. Timeout
B. Duplicate ACKs
C. Packet size increase
D. Routing failure
✅ Answer: B
Explanation:
When TCP receives 3 duplicate ACKs, it assumes:
A packet is lost
Retransmits immediately (without waiting for timeout)
8. AIMD stands for:
A. Additive Increase Multiplicative Decrease
B. Automatic Internet Message Delivery
C. Advanced IP Management Design
D. Adaptive Interface Model Design
✅ Answer: A
