WGU D413 TELECOMMUNICATIONS
NEWLY UPDATED COLLECTION OF EXAM
QUESTIONS AND VERIFIED ANSWERS
DESIGNED TO GUARANTEE YOUR
SUCCESS ON THE LATEST TEST VERSION
Question 1
Which layer of the OSI model is responsible for end-to-end error
recovery and flow control?
A) Physical layer
B) Data link layer
C) Transport layer
D) Application layer
Correct Answer: C) Transport layer
Rationale: The Transport layer (Layer 4) provides reliable data transfer,
error recovery, flow control, and segmentation. Protocols like TCP
operate at this layer to ensure end-to-end communication reliability. The
Physical layer handles raw bit transmission, the Data link layer manages
node-to-node delivery, and the Application layer provides user services.
,Question 2
The TCP/IP model combines which OSI layers into a single "Application
layer"?
A) Session, Presentation, Application
B) Physical, Data Link, Network
C) Network, Transport, Session
D) Data Link, Physical, Application
Correct Answer: A) Session, Presentation, Application
Rationale: The TCP/IP Application layer corresponds to OSI Layers 5, 6,
and 7 (Session, Presentation, and Application). The TCP/IP model
condenses the seven-layer OSI model into four layers: Application,
Transport, Internet, and Network Access.
Question 3
Which protocol operates at the transport layer of the TCP/IP model and
provides unreliable, connectionless communication?
A) TCP
B) UDP
C) IP
D) HTTP
Correct Answer: B) UDP
Rationale: UDP (User Datagram Protocol) is connectionless and does
not guarantee delivery, ordering, or error checking beyond basic
,checksums. In contrast, TCP provides reliable, connection-oriented
communication with error recovery and flow control.
Question 4
The Internet Protocol (IP) operates at which OSI layer?
A) Physical
B) Data Link
C) Network
D) Transport
Correct Answer: C) Network
Rationale: IP is a network layer (Layer 3) protocol responsible for logical
addressing and routing packets across networks. The Network layer
handles packet forwarding, addressing, and routing.
Question 5
Ethernet operates at which two OSI layers?
A) Physical and Data Link
B) Network and Transport
C) Session and Presentation
D) Application and Physical
Correct Answer: A) Physical and Data Link
, Rationale: Ethernet covers the Physical layer (signaling, bits) and Data
Link layer (MAC addressing, framing). The Data Link layer is further
divided into LLC and MAC sublayers.
Question 6
Which OSI layer is responsible for logical addressing and routing?
A) Physical
B) Data Link
C) Network
D) Transport
Correct Answer: C) Network
Rationale: The Network layer (Layer 3) handles logical addressing (e.g.,
IP addresses) and determines the best path for data transmission
through routing.
Question 7
At which OSI layer does a switch primarily operate?
A) Physical Layer
B) Data Link Layer
C) Network Layer
D) Transport Layer
Correct Answer: B) Data Link Layer
NEWLY UPDATED COLLECTION OF EXAM
QUESTIONS AND VERIFIED ANSWERS
DESIGNED TO GUARANTEE YOUR
SUCCESS ON THE LATEST TEST VERSION
Question 1
Which layer of the OSI model is responsible for end-to-end error
recovery and flow control?
A) Physical layer
B) Data link layer
C) Transport layer
D) Application layer
Correct Answer: C) Transport layer
Rationale: The Transport layer (Layer 4) provides reliable data transfer,
error recovery, flow control, and segmentation. Protocols like TCP
operate at this layer to ensure end-to-end communication reliability. The
Physical layer handles raw bit transmission, the Data link layer manages
node-to-node delivery, and the Application layer provides user services.
,Question 2
The TCP/IP model combines which OSI layers into a single "Application
layer"?
A) Session, Presentation, Application
B) Physical, Data Link, Network
C) Network, Transport, Session
D) Data Link, Physical, Application
Correct Answer: A) Session, Presentation, Application
Rationale: The TCP/IP Application layer corresponds to OSI Layers 5, 6,
and 7 (Session, Presentation, and Application). The TCP/IP model
condenses the seven-layer OSI model into four layers: Application,
Transport, Internet, and Network Access.
Question 3
Which protocol operates at the transport layer of the TCP/IP model and
provides unreliable, connectionless communication?
A) TCP
B) UDP
C) IP
D) HTTP
Correct Answer: B) UDP
Rationale: UDP (User Datagram Protocol) is connectionless and does
not guarantee delivery, ordering, or error checking beyond basic
,checksums. In contrast, TCP provides reliable, connection-oriented
communication with error recovery and flow control.
Question 4
The Internet Protocol (IP) operates at which OSI layer?
A) Physical
B) Data Link
C) Network
D) Transport
Correct Answer: C) Network
Rationale: IP is a network layer (Layer 3) protocol responsible for logical
addressing and routing packets across networks. The Network layer
handles packet forwarding, addressing, and routing.
Question 5
Ethernet operates at which two OSI layers?
A) Physical and Data Link
B) Network and Transport
C) Session and Presentation
D) Application and Physical
Correct Answer: A) Physical and Data Link
, Rationale: Ethernet covers the Physical layer (signaling, bits) and Data
Link layer (MAC addressing, framing). The Data Link layer is further
divided into LLC and MAC sublayers.
Question 6
Which OSI layer is responsible for logical addressing and routing?
A) Physical
B) Data Link
C) Network
D) Transport
Correct Answer: C) Network
Rationale: The Network layer (Layer 3) handles logical addressing (e.g.,
IP addresses) and determines the best path for data transmission
through routing.
Question 7
At which OSI layer does a switch primarily operate?
A) Physical Layer
B) Data Link Layer
C) Network Layer
D) Transport Layer
Correct Answer: B) Data Link Layer
