CS6250 – COMPUTER NETWORKS EXAM 1 100
QUESTIONS AND ANSWERS WITH ELABORATE
EXPLANATIONS 2026/2027
.
Section A: Networking Basics & Models (Q1–20)
Q1: Which layer of the OSI model is responsible for establishing, managing, and terminating
sessions between applications?
A) Transport
B) Session ✅
C) Presentation
D) Application
Answer: B) Session
Explanation: The Session layer (Layer 5) manages sessions between applications, including
setup, coordination, and termination of communication. Transport (Layer 4) handles end-to-end
delivery but not session management.
Q2: The TCP/IP model's equivalent of the OSI model’s Transport layer is:
A) Network Access
B) Internet
C) Transport ✅
D) Application
Answer: C) Transport
Explanation: TCP/IP has four layers: Application, Transport, Internet, and Network Access.
The Transport layer handles end-to-end delivery, flow control, and reliability, corresponding to
OSI Layer 4.
Q3: Which of the following is a connectionless protocol?
A) TCP
B) UDP ✅
C) FTP
D) HTTP
,Answer: B) UDP
Explanation: UDP is connectionless and does not guarantee delivery, ordering, or error
correction. TCP is connection-oriented, providing reliable communication.
Q4: The main function of the data link layer is:
A) Routing packets
B) Ensuring reliable end-to-end delivery
C) Framing and error detection ✅
D) Encrypting data
Answer: C) Framing and error detection
Explanation: The Data Link layer handles framing, MAC addressing, and error detection (e.g.,
CRC), ensuring correct delivery between adjacent nodes.
Q5: In the OSI model, which layer translates data between network format and application
format?
A) Session
B) Presentation ✅
C) Transport
D) Application
Answer: B) Presentation
Explanation: The Presentation layer (Layer 6) is responsible for data translation,
encryption/decryption, and compression to ensure interoperability between systems.
Q6: Which of the following is NOT a function of the Transport layer?
A) Flow control
B) Error detection and correction
C) Logical addressing ✅
D) Segmentation
Answer: C) Logical addressing
Explanation: Logical addressing (IP addresses) is handled by the Network layer (Layer 3), not
the Transport layer, which manages segmentation, flow control, and reliability.
Q7: Which of the following is an example of a network topology that connects all nodes to a
central hub?
A) Mesh
, B) Star ✅
C) Ring
D) Bus
Answer: B) Star
Explanation: In a Star topology, all nodes are connected to a central hub or switch, simplifying
management and fault isolation.
Q8: Which protocol is responsible for resolving IP addresses into MAC addresses?
A) DNS
B) ARP ✅
C) ICMP
D) RARP
Answer: B) ARP
Explanation: Address Resolution Protocol (ARP) maps a known IP address to its
corresponding MAC address on a local network.
Q9: What is the main advantage of using UDP over TCP?
A) Reliable delivery
B) Faster transmission ✅
C) Congestion control
D) Ordered data delivery
Answer: B) Faster transmission
Explanation: UDP has minimal overhead since it does not implement reliability, sequencing, or
congestion control, making it faster for applications like video streaming or gaming.
Q10: Which type of network device operates primarily at the Data Link layer?
A) Router
B) Switch ✅
C) Hub
D) Firewall
Answer: B) Switch
Explanation: Switches forward frames based on MAC addresses (Data Link layer), while
routers operate at Layer 3 (Network).
QUESTIONS AND ANSWERS WITH ELABORATE
EXPLANATIONS 2026/2027
.
Section A: Networking Basics & Models (Q1–20)
Q1: Which layer of the OSI model is responsible for establishing, managing, and terminating
sessions between applications?
A) Transport
B) Session ✅
C) Presentation
D) Application
Answer: B) Session
Explanation: The Session layer (Layer 5) manages sessions between applications, including
setup, coordination, and termination of communication. Transport (Layer 4) handles end-to-end
delivery but not session management.
Q2: The TCP/IP model's equivalent of the OSI model’s Transport layer is:
A) Network Access
B) Internet
C) Transport ✅
D) Application
Answer: C) Transport
Explanation: TCP/IP has four layers: Application, Transport, Internet, and Network Access.
The Transport layer handles end-to-end delivery, flow control, and reliability, corresponding to
OSI Layer 4.
Q3: Which of the following is a connectionless protocol?
A) TCP
B) UDP ✅
C) FTP
D) HTTP
,Answer: B) UDP
Explanation: UDP is connectionless and does not guarantee delivery, ordering, or error
correction. TCP is connection-oriented, providing reliable communication.
Q4: The main function of the data link layer is:
A) Routing packets
B) Ensuring reliable end-to-end delivery
C) Framing and error detection ✅
D) Encrypting data
Answer: C) Framing and error detection
Explanation: The Data Link layer handles framing, MAC addressing, and error detection (e.g.,
CRC), ensuring correct delivery between adjacent nodes.
Q5: In the OSI model, which layer translates data between network format and application
format?
A) Session
B) Presentation ✅
C) Transport
D) Application
Answer: B) Presentation
Explanation: The Presentation layer (Layer 6) is responsible for data translation,
encryption/decryption, and compression to ensure interoperability between systems.
Q6: Which of the following is NOT a function of the Transport layer?
A) Flow control
B) Error detection and correction
C) Logical addressing ✅
D) Segmentation
Answer: C) Logical addressing
Explanation: Logical addressing (IP addresses) is handled by the Network layer (Layer 3), not
the Transport layer, which manages segmentation, flow control, and reliability.
Q7: Which of the following is an example of a network topology that connects all nodes to a
central hub?
A) Mesh
, B) Star ✅
C) Ring
D) Bus
Answer: B) Star
Explanation: In a Star topology, all nodes are connected to a central hub or switch, simplifying
management and fault isolation.
Q8: Which protocol is responsible for resolving IP addresses into MAC addresses?
A) DNS
B) ARP ✅
C) ICMP
D) RARP
Answer: B) ARP
Explanation: Address Resolution Protocol (ARP) maps a known IP address to its
corresponding MAC address on a local network.
Q9: What is the main advantage of using UDP over TCP?
A) Reliable delivery
B) Faster transmission ✅
C) Congestion control
D) Ordered data delivery
Answer: B) Faster transmission
Explanation: UDP has minimal overhead since it does not implement reliability, sequencing, or
congestion control, making it faster for applications like video streaming or gaming.
Q10: Which type of network device operates primarily at the Data Link layer?
A) Router
B) Switch ✅
C) Hub
D) Firewall
Answer: B) Switch
Explanation: Switches forward frames based on MAC addresses (Data Link layer), while
routers operate at Layer 3 (Network).
