CS6250 COMPUTER NETWORKS – EXAM 1
COMPREHENSIVE PRACTICE EXAM (UPDATED
2026)
Section 1: Layered Architecture & The Internet Model (Q1-15)
Q1. What are the primary advantages of using a layered architecture in computer networks?
A. It eliminates all forms of network latency.
B. It allows for scalability, flexibility, and independent development of different layers.
C. It guarantees security for all network communications.
D. It simplifies hardware design by combining all protocols into a single module.
Answer: B
Rationale: Layering allows each layer to provide a specific service, making the system more scalable and
flexible. Changes to one layer do not affect others, promoting independent development and cost-
effective implementations .
Q2. What is the main difference between the 7-layer OSI model and the 5-layer Internet model?
A. The OSI model has a separate Network layer, while the Internet model does not.
B. The Internet model combines the Application, Presentation, and Session layers of the OSI model into
a single Application layer.
C. The OSI model does not have a Physical layer.
D. The Internet model has an additional "Internetwork" layer not present in OSI.
Answer: B
Rationale: The five-layer Internet model consolidates the top three layers of the OSI model (Application,
Presentation, Session) into one Application layer, simplifying the stack .
Q3. In the five-layer Internet model, which layer is responsible for moving frames from one node to
the next on the same network?
,A. Physical Layer
B. Network Layer
C. Transport Layer
D. Data Link Layer
Answer: D
Rationale: The Data Link layer handles the transfer of data frames across a single link (e.g., Ethernet, Wi-
Fi) from one node to the next .
Q4. Which of the following is a potential disadvantage of a strictly layered architecture?
A. Lack of scalability.
B. High cost of implementation due to complex hardware.
C. Overhead caused by abstraction barriers between layers.
D. Inability to support multiple protocols.
Answer: C
Rationale: The abstraction barriers between layers can add overhead in both computation and message
headers (e.g., headers added at each layer), which is a noted disadvantage of layered models .
Q5. Provide examples of protocols at the Application, Transport, and Network layers of the Internet
model.
Answer:
Application Layer: HTTP, DNS, SMTP, FTP .
Transport Layer: TCP, UDP .
Network Layer: IP (IPv4, IPv6), ARP, ICMP .
Q6. What is the primary function of the Presentation layer in the OSI model?
A. Managing different transport streams for a session (e.g., audio and video).
B. Formatting or translating data (e.g., encryption, compression).
C. Providing end-to-end communication and reliability.
D. Routing packets across multiple networks.
Answer: B
Rationale: The Presentation layer acts as a translator, handling data formatting, encryption, and
compression to present data properly to the Application layer .
Q7. What is encapsulation?
Answer: Encapsulation is the process where data is passed down the protocol stack, and each layer
adds its own header (and sometimes trailer) information. This header contains control information for
the corresponding layer on the receiving end .
, Q8. A network socket serves as:
A. The physical hardware that connects a computer to the network.
B. The software interface between the Application layer and the Transport layer.
C. The routing table used by the Network layer.
D. The protocol used for web browsing.
Answer: B
Rationale: A socket is the software endpoint for communication, providing the interface between an
application process and the transport layer protocols (TCP/UDP) .
Q9. True or False: Repeaters and Hubs operate at the Network Layer (Layer 3).
Answer: False
Rationale: Repeaters and hubs operate at the Physical Layer (Layer 1), simply regenerating and
broadcasting signals .
Q10. Which of the following devices operates at the Data Link Layer?
A. Router
B. Repeater
C. Bridge
D. Firewall (stateless)
Answer: C
Rationale: Bridges operate at the Data Link Layer (Layer 2), using MAC addresses to filter and forward
traffic between network segments .
Q11. True or False: The End-to-End (e2e) principle suggests that network core functions should be
complex and intelligent, while the end systems should be simple.
Answer: False
Rationale: The End-to-End principle states the opposite: the network core should be simple and
minimal, while intelligence and complex functions (like error recovery) should be implemented at the
end hosts .
Q12. Which of the following is cited as a violation of the End-to-End principle?
A. The use of HTTP for web browsing.
B. The use of TCP for reliable transmission.
C. The use of Network Address Translation (NAT) boxes.
D. The use of IP addresses for routing.
Answer: C
Rationale: NAT boxes violate the principle because they act as intermediate devices that modify packet
headers and maintain state, breaking the end-to-end transparency of the network .
COMPREHENSIVE PRACTICE EXAM (UPDATED
2026)
Section 1: Layered Architecture & The Internet Model (Q1-15)
Q1. What are the primary advantages of using a layered architecture in computer networks?
A. It eliminates all forms of network latency.
B. It allows for scalability, flexibility, and independent development of different layers.
C. It guarantees security for all network communications.
D. It simplifies hardware design by combining all protocols into a single module.
Answer: B
Rationale: Layering allows each layer to provide a specific service, making the system more scalable and
flexible. Changes to one layer do not affect others, promoting independent development and cost-
effective implementations .
Q2. What is the main difference between the 7-layer OSI model and the 5-layer Internet model?
A. The OSI model has a separate Network layer, while the Internet model does not.
B. The Internet model combines the Application, Presentation, and Session layers of the OSI model into
a single Application layer.
C. The OSI model does not have a Physical layer.
D. The Internet model has an additional "Internetwork" layer not present in OSI.
Answer: B
Rationale: The five-layer Internet model consolidates the top three layers of the OSI model (Application,
Presentation, Session) into one Application layer, simplifying the stack .
Q3. In the five-layer Internet model, which layer is responsible for moving frames from one node to
the next on the same network?
,A. Physical Layer
B. Network Layer
C. Transport Layer
D. Data Link Layer
Answer: D
Rationale: The Data Link layer handles the transfer of data frames across a single link (e.g., Ethernet, Wi-
Fi) from one node to the next .
Q4. Which of the following is a potential disadvantage of a strictly layered architecture?
A. Lack of scalability.
B. High cost of implementation due to complex hardware.
C. Overhead caused by abstraction barriers between layers.
D. Inability to support multiple protocols.
Answer: C
Rationale: The abstraction barriers between layers can add overhead in both computation and message
headers (e.g., headers added at each layer), which is a noted disadvantage of layered models .
Q5. Provide examples of protocols at the Application, Transport, and Network layers of the Internet
model.
Answer:
Application Layer: HTTP, DNS, SMTP, FTP .
Transport Layer: TCP, UDP .
Network Layer: IP (IPv4, IPv6), ARP, ICMP .
Q6. What is the primary function of the Presentation layer in the OSI model?
A. Managing different transport streams for a session (e.g., audio and video).
B. Formatting or translating data (e.g., encryption, compression).
C. Providing end-to-end communication and reliability.
D. Routing packets across multiple networks.
Answer: B
Rationale: The Presentation layer acts as a translator, handling data formatting, encryption, and
compression to present data properly to the Application layer .
Q7. What is encapsulation?
Answer: Encapsulation is the process where data is passed down the protocol stack, and each layer
adds its own header (and sometimes trailer) information. This header contains control information for
the corresponding layer on the receiving end .
, Q8. A network socket serves as:
A. The physical hardware that connects a computer to the network.
B. The software interface between the Application layer and the Transport layer.
C. The routing table used by the Network layer.
D. The protocol used for web browsing.
Answer: B
Rationale: A socket is the software endpoint for communication, providing the interface between an
application process and the transport layer protocols (TCP/UDP) .
Q9. True or False: Repeaters and Hubs operate at the Network Layer (Layer 3).
Answer: False
Rationale: Repeaters and hubs operate at the Physical Layer (Layer 1), simply regenerating and
broadcasting signals .
Q10. Which of the following devices operates at the Data Link Layer?
A. Router
B. Repeater
C. Bridge
D. Firewall (stateless)
Answer: C
Rationale: Bridges operate at the Data Link Layer (Layer 2), using MAC addresses to filter and forward
traffic between network segments .
Q11. True or False: The End-to-End (e2e) principle suggests that network core functions should be
complex and intelligent, while the end systems should be simple.
Answer: False
Rationale: The End-to-End principle states the opposite: the network core should be simple and
minimal, while intelligence and complex functions (like error recovery) should be implemented at the
end hosts .
Q12. Which of the following is cited as a violation of the End-to-End principle?
A. The use of HTTP for web browsing.
B. The use of TCP for reliable transmission.
C. The use of Network Address Translation (NAT) boxes.
D. The use of IP addresses for routing.
Answer: C
Rationale: NAT boxes violate the principle because they act as intermediate devices that modify packet
headers and maintain state, breaking the end-to-end transparency of the network .
