,WGU D315 Pre-Assessment | Network and Security Foundations
(2026/2027) Practice Q&A | WGU
1. Which layer of the OSI model is responsible for translating data between the application
layer and the network format?
A) Application
B) Presentation
C) Session
D) Transport
Correct Answer: Presentation
Rationale: The Presentation layer, Layer 6, handles data translation, encryption, and
compression between the application and network formats. The Application layer provides
network services to users, the Session layer manages connections, and the Transport layer
handles end-to-end delivery.
2. What is the primary function of the Session layer in the OSI model?
A) Logical addressing
B) Data formatting
C) Establishing, managing, and terminating connections
D) Physical transmission
Correct Answer: Establishing, managing, and terminating connections
Rationale: The Session layer, Layer 5, establishes, manages, and terminates
communication sessions between applications. Logical addressing is handled by the
,Network layer, data formatting by the Presentation layer, and physical transmission by the
Physical layer.
3. Which OSI layer is responsible for organizing how bits are passed over the physical
medium within a collision domain?
A) Physical
B) Data Link
C) Network
D) Transport
Correct Answer: Data Link
Rationale: The Data Link layer, Layer 2, organizes how bits are passed over the physical
layer between devices within the same collision domain, handling framing and MAC
addressing. The Physical layer transmits raw bits, the Network layer handles routing, and
the Transport layer manages end-to-end delivery.
4. In the TCP/IP model, which layer corresponds to the OSI Data Link and Physical layers
combined?
A) Application
B) Transport
C) Internet
D) Network Access
Correct Answer: Network Access
Rationale: The TCP/IP Network Access layer encompasses the functions of the OSI Data
Link and Physical layers, handling physical transmission and local frame delivery. The
, Application layer maps to OSI layers 5–7, the Transport layer to Layer 4, and the Internet
layer to Layer 3.
5. Which protocol operates at the Transport layer and provides connectionless, unreliable
delivery?
A) TCP
B) UDP
C) IP
D) ICMP
Correct Answer: UDP
Rationale: UDP operates at the Transport layer and provides connectionless, unreliable
delivery without acknowledgments or retransmission. TCP provides reliable, connection-
oriented delivery, IP operates at the Network layer, and ICMP supports diagnostic
messaging.
6. What is the primary purpose of the Internet Control Message Protocol?
A) To assign IP addresses dynamically
B) To resolve domain names to IP addresses
C) To provide diagnostic and control messaging
D) To encrypt network traffic
Correct Answer: To provide diagnostic and control messaging
Rationale: ICMP provides diagnostic and control messaging, such as echo requests used
by the ping utility to test connectivity. DHCP assigns IP addresses, DNS resolves names, and
encryption protocols protect traffic.
(2026/2027) Practice Q&A | WGU
1. Which layer of the OSI model is responsible for translating data between the application
layer and the network format?
A) Application
B) Presentation
C) Session
D) Transport
Correct Answer: Presentation
Rationale: The Presentation layer, Layer 6, handles data translation, encryption, and
compression between the application and network formats. The Application layer provides
network services to users, the Session layer manages connections, and the Transport layer
handles end-to-end delivery.
2. What is the primary function of the Session layer in the OSI model?
A) Logical addressing
B) Data formatting
C) Establishing, managing, and terminating connections
D) Physical transmission
Correct Answer: Establishing, managing, and terminating connections
Rationale: The Session layer, Layer 5, establishes, manages, and terminates
communication sessions between applications. Logical addressing is handled by the
,Network layer, data formatting by the Presentation layer, and physical transmission by the
Physical layer.
3. Which OSI layer is responsible for organizing how bits are passed over the physical
medium within a collision domain?
A) Physical
B) Data Link
C) Network
D) Transport
Correct Answer: Data Link
Rationale: The Data Link layer, Layer 2, organizes how bits are passed over the physical
layer between devices within the same collision domain, handling framing and MAC
addressing. The Physical layer transmits raw bits, the Network layer handles routing, and
the Transport layer manages end-to-end delivery.
4. In the TCP/IP model, which layer corresponds to the OSI Data Link and Physical layers
combined?
A) Application
B) Transport
C) Internet
D) Network Access
Correct Answer: Network Access
Rationale: The TCP/IP Network Access layer encompasses the functions of the OSI Data
Link and Physical layers, handling physical transmission and local frame delivery. The
, Application layer maps to OSI layers 5–7, the Transport layer to Layer 4, and the Internet
layer to Layer 3.
5. Which protocol operates at the Transport layer and provides connectionless, unreliable
delivery?
A) TCP
B) UDP
C) IP
D) ICMP
Correct Answer: UDP
Rationale: UDP operates at the Transport layer and provides connectionless, unreliable
delivery without acknowledgments or retransmission. TCP provides reliable, connection-
oriented delivery, IP operates at the Network layer, and ICMP supports diagnostic
messaging.
6. What is the primary purpose of the Internet Control Message Protocol?
A) To assign IP addresses dynamically
B) To resolve domain names to IP addresses
C) To provide diagnostic and control messaging
D) To encrypt network traffic
Correct Answer: To provide diagnostic and control messaging
Rationale: ICMP provides diagnostic and control messaging, such as echo requests used
by the ping utility to test connectivity. DHCP assigns IP addresses, DNS resolves names, and
encryption protocols protect traffic.
