Computer Networking mid term Exam Review
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rationales/graded A+/2026 update/100% correct
/instant download
Computer Networking – Midterm Exam Review (200 Questions)
Topics Covered (Typical First Half)
• OSI & TCP/IP Models (Layers, encapsulation, PDUs)
• Physical Layer (signals, media, encoding, bandwidth)
• Data Link Layer (MAC, Ethernet, switches, ARP, error detection)
• Network Layer (IP addressing, subnetting, CIDR, NAT, ICMP, IPv6 basics)
• Transport Layer (TCP vs UDP, ports, TCP header, connection management
basics)
• Application Layer (DNS, HTTP, FTP, SMTP – introduction)
• Basic Network Security (firewalls, common attacks)
Q1. Which layer of the OSI model is responsible for transmitting raw bits over a
physical medium?
A) Data Link
B) Physical
C) Network
D) Transport
,Answer: B
Rationale: The Physical Layer (Layer 1) handles bits, signaling, cabling, and
connectors.
Q2. What is the PDU (Protocol Data Unit) at the Data Link Layer?
A) Bit
B) Frame
C) Packet
D) Segment
Answer: B
Rationale: Data Link layer PDU is a frame (includes header, payload, trailer).
Q3. Which OSI layer is responsible for logical addressing (IP addresses) and
routing?
A) Data Link
B) Physical
C) Network
D) Transport
Answer: C
Rationale: The Network Layer (Layer 3) handles logical addressing and packet
forwarding.
Q4. The TCP/IP model has how many layers?
A) 4 layers
B) 5 layers
C) 7 layers
D) 3 layers
,Answer: A
Rationale: TCP/IP model: Network Interface, Internet, Transport, Application (4
layers).
Q5. Which OSI layer provides end-to-end error recovery and flow control?
A) Network
B) Data Link
C) Session
D) Transport
Answer: D
Rationale: Transport Layer (Layer 4) provides reliability (TCP) or unreliable (UDP).
Q6. What is encapsulation in networking?
A) Adding headers (and trailers) as data moves down the protocol stack
B) Removing headers as data moves up
C) Encrypting data
D) Compressing data
Answer: A
Rationale: Each layer adds its own header (and sometimes trailer) to the data.
Q7. Which of the following is NOT a function of the Data Link Layer?
A) Framing
B) MAC addressing
C) Error detection (CRC)
D) Routing
Answer: D
Rationale: Routing is a Network Layer function; Data Link handles local delivery.
, Q8. What is the maximum theoretical throughput of a 1000 Mbps (1 Gbps)
Ethernet link in bytes per second?
A) 125 MB/s
B) 1000 MB/s
C) 1 GB/s
D) 125 MB/s (theoretical)
Answer: A
Rationale: 1 Gbps ÷ 8 = 125 MB/s (theoretical; actual is less due to overhead).
Q9. Which guided transmission medium is most resistant to electromagnetic
interference (EMI)?
A) Unshielded twisted pair (UTP)
B) Shielded twisted pair (STP)
C) Coaxial cable
D) Fiber optic
Answer: D
Rationale: Fiber optic uses light, not electricity, so it is immune to EMI.
Q10. Which encoding scheme uses voltage transitions to represent bits?
A) NRZ
B) Manchester encoding
C) AMI
D) 4B/5B
Answer: B
Rationale: Manchester encoding has a transition at every bit period, enabling
clock recovery.
Q11. What is the maximum length of a 10Base-T Ethernet segment?
A) 100 meters
2026|||questions and answers with
rationales/graded A+/2026 update/100% correct
/instant download
Computer Networking – Midterm Exam Review (200 Questions)
Topics Covered (Typical First Half)
• OSI & TCP/IP Models (Layers, encapsulation, PDUs)
• Physical Layer (signals, media, encoding, bandwidth)
• Data Link Layer (MAC, Ethernet, switches, ARP, error detection)
• Network Layer (IP addressing, subnetting, CIDR, NAT, ICMP, IPv6 basics)
• Transport Layer (TCP vs UDP, ports, TCP header, connection management
basics)
• Application Layer (DNS, HTTP, FTP, SMTP – introduction)
• Basic Network Security (firewalls, common attacks)
Q1. Which layer of the OSI model is responsible for transmitting raw bits over a
physical medium?
A) Data Link
B) Physical
C) Network
D) Transport
,Answer: B
Rationale: The Physical Layer (Layer 1) handles bits, signaling, cabling, and
connectors.
Q2. What is the PDU (Protocol Data Unit) at the Data Link Layer?
A) Bit
B) Frame
C) Packet
D) Segment
Answer: B
Rationale: Data Link layer PDU is a frame (includes header, payload, trailer).
Q3. Which OSI layer is responsible for logical addressing (IP addresses) and
routing?
A) Data Link
B) Physical
C) Network
D) Transport
Answer: C
Rationale: The Network Layer (Layer 3) handles logical addressing and packet
forwarding.
Q4. The TCP/IP model has how many layers?
A) 4 layers
B) 5 layers
C) 7 layers
D) 3 layers
,Answer: A
Rationale: TCP/IP model: Network Interface, Internet, Transport, Application (4
layers).
Q5. Which OSI layer provides end-to-end error recovery and flow control?
A) Network
B) Data Link
C) Session
D) Transport
Answer: D
Rationale: Transport Layer (Layer 4) provides reliability (TCP) or unreliable (UDP).
Q6. What is encapsulation in networking?
A) Adding headers (and trailers) as data moves down the protocol stack
B) Removing headers as data moves up
C) Encrypting data
D) Compressing data
Answer: A
Rationale: Each layer adds its own header (and sometimes trailer) to the data.
Q7. Which of the following is NOT a function of the Data Link Layer?
A) Framing
B) MAC addressing
C) Error detection (CRC)
D) Routing
Answer: D
Rationale: Routing is a Network Layer function; Data Link handles local delivery.
, Q8. What is the maximum theoretical throughput of a 1000 Mbps (1 Gbps)
Ethernet link in bytes per second?
A) 125 MB/s
B) 1000 MB/s
C) 1 GB/s
D) 125 MB/s (theoretical)
Answer: A
Rationale: 1 Gbps ÷ 8 = 125 MB/s (theoretical; actual is less due to overhead).
Q9. Which guided transmission medium is most resistant to electromagnetic
interference (EMI)?
A) Unshielded twisted pair (UTP)
B) Shielded twisted pair (STP)
C) Coaxial cable
D) Fiber optic
Answer: D
Rationale: Fiber optic uses light, not electricity, so it is immune to EMI.
Q10. Which encoding scheme uses voltage transitions to represent bits?
A) NRZ
B) Manchester encoding
C) AMI
D) 4B/5B
Answer: B
Rationale: Manchester encoding has a transition at every bit period, enabling
clock recovery.
Q11. What is the maximum length of a 10Base-T Ethernet segment?
A) 100 meters
