Computer Networking comprehesive Exam Review
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Computer Networking – Comprehensive Exam Review (250 Questions)
Full Coverage Topics
• OSI & TCP/IP Models (Layers, encapsulation, PDUs)
• Physical Layer (signals, encoding, media, bandwidth)
• Data Link Layer (MAC, Ethernet, switches, VLANs, error detection)
• Network Layer (IP addressing, subnetting, routing, NAT, ICMP, IPv6)
• Transport Layer (TCP/UDP, ports, congestion control, flow control)
• Application Layer (HTTP/HTTPS, DNS, SMTP, FTP, DHCP, TLS)
• Network Security (firewalls, VPNs, IDS/IPS, attacks, mitigation)
• Wireless & Mobile (802.11, Bluetooth, cellular, 5G)
• Multimedia & QoS (VoIP, streaming, jitter, latency)
• Network Management (SNMP, NetFlow, SDN)
• Advanced Topics (BGP, MPLS, CDN, IoT networking)
Q1. Which layer of the OSI model is responsible for reliable data delivery and error recovery?
A) Network
B) Transport
C) Data Link
D) Session
Answer: B
Rationale: The Transport Layer (Layer 4) provides end-to-end reliability (TCP).
,Q2. What is the PDU at the Network Layer?
A) Frame
B) Packet
C) Segment
D) Bit
Answer: B
Rationale: Network layer PDU is a packet (IP datagram).
Q3. Which OSI layer is responsible for frame delimiting and MAC addressing?
A) Physical
B) Data Link
C) Network
D) Transport
Answer: B
Rationale: The Data Link Layer (Layer 2) handles framing, MAC addresses, and error detection.
Q4. The TCP/IP Application Layer maps to which OSI layers?
A) Application, Presentation, Session
B) Session only
C) Presentation only
D) Application only
Answer: A
Rationale: TCP/IP combines session, presentation, and application into one layer.
Q5. Which of the following is NOT a function of the Session Layer?
A) Session establishment and teardown
B) Checkpointing and recovery
C) Encryption
D) Dialog control (half-duplex/full-duplex)
Answer: C
Rationale: Encryption is typically a Presentation Layer function.
,Q6. What is the purpose of the Presentation Layer?
A) Data formatting, translation, compression, encryption
B) Routing
C) MAC addressing
D) Flow control
Answer: A
Rationale: Presentation layer handles syntax and semantics of data.
Q7. What is a protocol data unit (PDU) at the Physical Layer?
A) Bit
B) Frame
C) Packet
D) Segment
Answer: A
Rationale: Physical layer PDU is a bit (or symbol).
Q8. Which of the following is a connectionless protocol?
A) TCP
B) UDP
C) HTTP
D) FTP
Answer: B
Rationale: UDP provides no connection setup, reliability, or ordering.
Q9. What is the maximum throughput of a 100 Mbps Ethernet link in bytes per second?
A) 12.5 MB/s
B) 100 MB/s
C) 1 GB/s
D) 125 MB/s
Answer: A
Rationale: 100 Mbps ÷ 8 = 12.5 MB/s (theoretical; actual is less due to overhead).
, Q10. Which guided 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.
Q11. Which encoding scheme is used in 10Base-T Ethernet?
A) Manchester
B) NRZ
C) 4B/5B
D) 8B/10B
Answer: A
Rationale: Manchester encoding ensures clock recovery with a transition every bit period.
Q12. What is the maximum length of a 10Base-T segment?
A) 100 meters
B) 185 meters
C) 500 meters
D) 2 kilometers
Answer: A
Rationale: 10Base-T (twisted pair) maximum length is 100 meters.
Q13. What is CSMA/CD in Ethernet?
A) Listen before transmitting, detect collision, jam, and back off
B) Avoid collisions by using RTS/CTS
C) Token passing
D) Centralized polling
Answer: A
Rationale: CSMA/CD is used in half-duplex Ethernet (now largely obsolete due to switches).
2026|||questions and answers with
rationales/graded A+/2026 update/100% correct
/instant download
Computer Networking – Comprehensive Exam Review (250 Questions)
Full Coverage Topics
• OSI & TCP/IP Models (Layers, encapsulation, PDUs)
• Physical Layer (signals, encoding, media, bandwidth)
• Data Link Layer (MAC, Ethernet, switches, VLANs, error detection)
• Network Layer (IP addressing, subnetting, routing, NAT, ICMP, IPv6)
• Transport Layer (TCP/UDP, ports, congestion control, flow control)
• Application Layer (HTTP/HTTPS, DNS, SMTP, FTP, DHCP, TLS)
• Network Security (firewalls, VPNs, IDS/IPS, attacks, mitigation)
• Wireless & Mobile (802.11, Bluetooth, cellular, 5G)
• Multimedia & QoS (VoIP, streaming, jitter, latency)
• Network Management (SNMP, NetFlow, SDN)
• Advanced Topics (BGP, MPLS, CDN, IoT networking)
Q1. Which layer of the OSI model is responsible for reliable data delivery and error recovery?
A) Network
B) Transport
C) Data Link
D) Session
Answer: B
Rationale: The Transport Layer (Layer 4) provides end-to-end reliability (TCP).
,Q2. What is the PDU at the Network Layer?
A) Frame
B) Packet
C) Segment
D) Bit
Answer: B
Rationale: Network layer PDU is a packet (IP datagram).
Q3. Which OSI layer is responsible for frame delimiting and MAC addressing?
A) Physical
B) Data Link
C) Network
D) Transport
Answer: B
Rationale: The Data Link Layer (Layer 2) handles framing, MAC addresses, and error detection.
Q4. The TCP/IP Application Layer maps to which OSI layers?
A) Application, Presentation, Session
B) Session only
C) Presentation only
D) Application only
Answer: A
Rationale: TCP/IP combines session, presentation, and application into one layer.
Q5. Which of the following is NOT a function of the Session Layer?
A) Session establishment and teardown
B) Checkpointing and recovery
C) Encryption
D) Dialog control (half-duplex/full-duplex)
Answer: C
Rationale: Encryption is typically a Presentation Layer function.
,Q6. What is the purpose of the Presentation Layer?
A) Data formatting, translation, compression, encryption
B) Routing
C) MAC addressing
D) Flow control
Answer: A
Rationale: Presentation layer handles syntax and semantics of data.
Q7. What is a protocol data unit (PDU) at the Physical Layer?
A) Bit
B) Frame
C) Packet
D) Segment
Answer: A
Rationale: Physical layer PDU is a bit (or symbol).
Q8. Which of the following is a connectionless protocol?
A) TCP
B) UDP
C) HTTP
D) FTP
Answer: B
Rationale: UDP provides no connection setup, reliability, or ordering.
Q9. What is the maximum throughput of a 100 Mbps Ethernet link in bytes per second?
A) 12.5 MB/s
B) 100 MB/s
C) 1 GB/s
D) 125 MB/s
Answer: A
Rationale: 100 Mbps ÷ 8 = 12.5 MB/s (theoretical; actual is less due to overhead).
, Q10. Which guided 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.
Q11. Which encoding scheme is used in 10Base-T Ethernet?
A) Manchester
B) NRZ
C) 4B/5B
D) 8B/10B
Answer: A
Rationale: Manchester encoding ensures clock recovery with a transition every bit period.
Q12. What is the maximum length of a 10Base-T segment?
A) 100 meters
B) 185 meters
C) 500 meters
D) 2 kilometers
Answer: A
Rationale: 10Base-T (twisted pair) maximum length is 100 meters.
Q13. What is CSMA/CD in Ethernet?
A) Listen before transmitting, detect collision, jam, and back off
B) Avoid collisions by using RTS/CTS
C) Token passing
D) Centralized polling
Answer: A
Rationale: CSMA/CD is used in half-duplex Ethernet (now largely obsolete due to switches).
