WGU D413 – Telecommunications & Wireless
Communications Objective Assessment OA V1 and V2
Questions and Answers 2026 Update 100% Correct.
WGU D413 – TELECOMMUNICATIONS & WIRELESS COMMUNICATIONS
Objective Assessment OA V1 & V2 200+ Practice Questions with Verified
Answers | 2026 Update
# PART 1: OSI MODEL & NETWORK PROTOCOLS
Q1. Which layer of the OSI model handles end-to-end flow control, error
detection, and reliable data delivery via retransmissions?
A) Network Layer
B) Data Link Layer
C) Transport Layer
D) Session Layer
Correct Answer: C – Transport Layer
Rationale: The Transport Layer (Layer 4) manages end-to-end communication
control, ensuring packets arrive error-free, in sequence, and without loss using
protocols like TCP .
1
,Q2. What is the primary operational data unit handled at the Data Link Layer
(Layer 2) of the OSI model?
A) Segment
B) Packet
C) Frame
D) Bit
Correct Answer: C – Frame
Rationale: Data at Layer 2 is packaged into frames containing physical MAC
addresses. Segments belong to Layer 4, packets to Layer 3, and bits to Layer 1 .
Q3. Which OSI layer is responsible for establishing, managing, coordinating, and
terminating conversations and dialogues between applications?
A) Application Layer
B) Presentation Layer
C) Session Layer
2
,D) Transport Layer
Correct Answer: C – Session Layer
Rationale: The Session Layer (Layer 5) opens, maintains, synchronizes, and closes
authentication and communication sessions between local and remote applications
.
Q4. Which protocol provides connectionless, unreliable transport without error
recovery or flow control for time-sensitive applications?
A) TCP
B) UDP
C) FTP
D) SSH
Correct Answer: B – UDP
Rationale: User Datagram Protocol (UDP) is connectionless and does not
guarantee delivery, error recovery, or flow control. It is used for time-sensitive
applications like VoIP and streaming where speed is prioritized over reliability .
3
, Q5. What is the purpose of a MAC address?
A) To identify a device on a network at the Network layer
B) To identify a device on a network at the Data Link layer
C) To identify a network application
D) To encrypt network traffic
Correct Answer: B – To identify a device on a network at the Data Link layer
Rationale: A MAC (Media Access Control) address is a 48-bit physical address
assigned to a network interface card (NIC) for identification at the Data Link layer
(Layer 2) within a local network .
Q6. What is the main job of the Address Resolution Protocol (ARP) on an Internet
Protocol version 4 network?
A) To resolve a domain name to an IP address
B) To resolve an IP address to a MAC address
C) To resolve a MAC address to an IP address
4
Communications Objective Assessment OA V1 and V2
Questions and Answers 2026 Update 100% Correct.
WGU D413 – TELECOMMUNICATIONS & WIRELESS COMMUNICATIONS
Objective Assessment OA V1 & V2 200+ Practice Questions with Verified
Answers | 2026 Update
# PART 1: OSI MODEL & NETWORK PROTOCOLS
Q1. Which layer of the OSI model handles end-to-end flow control, error
detection, and reliable data delivery via retransmissions?
A) Network Layer
B) Data Link Layer
C) Transport Layer
D) Session Layer
Correct Answer: C – Transport Layer
Rationale: The Transport Layer (Layer 4) manages end-to-end communication
control, ensuring packets arrive error-free, in sequence, and without loss using
protocols like TCP .
1
,Q2. What is the primary operational data unit handled at the Data Link Layer
(Layer 2) of the OSI model?
A) Segment
B) Packet
C) Frame
D) Bit
Correct Answer: C – Frame
Rationale: Data at Layer 2 is packaged into frames containing physical MAC
addresses. Segments belong to Layer 4, packets to Layer 3, and bits to Layer 1 .
Q3. Which OSI layer is responsible for establishing, managing, coordinating, and
terminating conversations and dialogues between applications?
A) Application Layer
B) Presentation Layer
C) Session Layer
2
,D) Transport Layer
Correct Answer: C – Session Layer
Rationale: The Session Layer (Layer 5) opens, maintains, synchronizes, and closes
authentication and communication sessions between local and remote applications
.
Q4. Which protocol provides connectionless, unreliable transport without error
recovery or flow control for time-sensitive applications?
A) TCP
B) UDP
C) FTP
D) SSH
Correct Answer: B – UDP
Rationale: User Datagram Protocol (UDP) is connectionless and does not
guarantee delivery, error recovery, or flow control. It is used for time-sensitive
applications like VoIP and streaming where speed is prioritized over reliability .
3
, Q5. What is the purpose of a MAC address?
A) To identify a device on a network at the Network layer
B) To identify a device on a network at the Data Link layer
C) To identify a network application
D) To encrypt network traffic
Correct Answer: B – To identify a device on a network at the Data Link layer
Rationale: A MAC (Media Access Control) address is a 48-bit physical address
assigned to a network interface card (NIC) for identification at the Data Link layer
(Layer 2) within a local network .
Q6. What is the main job of the Address Resolution Protocol (ARP) on an Internet
Protocol version 4 network?
A) To resolve a domain name to an IP address
B) To resolve an IP address to a MAC address
C) To resolve a MAC address to an IP address
4
