1
WGU D413 OBJECTIVE ASSESSMENT 2 LATEST
2026 ACTUAL EXAM TEST BANK| D413
TELECOMM AND WIRELESS
Section 1: OSI Model & Core Networking (Questions 1–25)
1. At which layer of the OSI model does a switch primarily operate when forwarding frames based on
MAC addresses?
A B C D
Physical Data Link Network Transport
Answer: B — Data Link. Switches make forwarding decisions based on MAC addresses, which reside at
Layer 2 (Data Link). Hubs operate at Layer 1, and routers operate at Layer 3.
2. Which layer of the OSI model is responsible for establishing, managing, and terminating sessions
between applications?
A B C D
Transport Session Presentation Application
Answer: B — Session. The Session layer (Layer 5) sets up, coordinates, and terminates conversations
between applications at each end.
3. Which device separates collision domains but not broadcast domains?
A B C D
Hub Repeater Switch Router
Answer: C — Switch. Switches create separate collision domains per port, but all ports on a switch
belong to the same broadcast domain unless VLANs are configured.
,2
4. Which protocol is used to resolve an IPv4 address to a MAC address?
A B C D
DNS DHCP ARP ICMP
Answer: C — ARP. Address Resolution Protocol maps a known IP address to its corresponding MAC
address on a local network.
5. What is the primary purpose of a subnet mask?
A B C D
To define which portion of an IP To assign MAC
To encrypt To monitor network
address is the network and addresses
data packets traffic for anomalies
which is the host dynamically
Answer: B — Subnet masks divide an IP address into network and host portions, allowing proper
routing and subnetting.
6. Which OSI layer is responsible for reliable data delivery, error detection, and retransmission?
A B C D
Network Layer Data Link Layer Transport Layer Physical Layer
Answer: C — Transport Layer. Layer 4 manages end-to-end communication, error recovery, flow
control, and segmentation. TCP operates at this layer.
7. Which component converts digital signals into analog signals for transmission over traditional phone
lines?
A B C D
Router Switch Modem Repeater
Answer: C — Modem. A modem (modulator-demodulator) converts digital data to analog for
transmission over analog lines (like POTS) and back again.
,3
8. What is the primary purpose of multiplexing?
A B C D
Error Combining multiple signals into one Increasing signal Encrypting
correction channel strength data
Answer: B — Multiplexing allows multiple data streams to share a single transmission medium,
improving efficiency. Common methods include TDM and FDM.
9. Which transmission medium provides the highest bandwidth and lowest signal loss?
A B C D
Coaxial cable Twisted pair Fiber-optic cable Microwave
Answer: C — Fiber-optic cable. Fiber transmits data as light pulses, offering extremely high bandwidth
and minimal interference.
10. What does latency measure?
A B C D
Error rate Bandwidth Delay in transmission Signal strength
Answer: C — Latency is the time delay between sending and receiving data.
11. Which layer of the OSI model is responsible for routing packets across different networks?
A B C D
Physical Data Link Network Transport
Answer: C — Network Layer. Routers operate at Layer 3 to determine optimal paths and forward
packets between different networks.
, 4
12. Which OSI layer defines the mechanical, electrical, and procedural characteristics to establish,
maintain, and deactivate physical links?
A B C D
Data Link Layer Physical Layer Network Layer Transport Layer
Answer: B — Physical Layer. Layer 1 deals with hardware transmission technologies such as cabling,
connectors, and signal specifications.
13. Which OSI layer is responsible for encryption, decryption, and data compression?
A B C D
Session Layer Presentation Layer Application Layer Transport Layer
Answer: B — Presentation Layer. Layer 6 translates data formats, encrypts/decrypts, and compresses
data for application layer use.
14. Which protocol operates at the Network layer and is responsible for logical addressing and routing?
A B C D
TCP UDP IP Ethernet
Answer: C — IP (Internet Protocol) operates at Layer 3 and handles logical addressing (IP addresses)
and packet routing.
15. Which of the following is a connection-oriented protocol that guarantees delivery?
A B C D
UDP IP TCP ICMP
Answer: C — TCP (Transmission Control Protocol) uses acknowledgments, sequencing, and flow
control to ensure reliable data delivery.
WGU D413 OBJECTIVE ASSESSMENT 2 LATEST
2026 ACTUAL EXAM TEST BANK| D413
TELECOMM AND WIRELESS
Section 1: OSI Model & Core Networking (Questions 1–25)
1. At which layer of the OSI model does a switch primarily operate when forwarding frames based on
MAC addresses?
A B C D
Physical Data Link Network Transport
Answer: B — Data Link. Switches make forwarding decisions based on MAC addresses, which reside at
Layer 2 (Data Link). Hubs operate at Layer 1, and routers operate at Layer 3.
2. Which layer of the OSI model is responsible for establishing, managing, and terminating sessions
between applications?
A B C D
Transport Session Presentation Application
Answer: B — Session. The Session layer (Layer 5) sets up, coordinates, and terminates conversations
between applications at each end.
3. Which device separates collision domains but not broadcast domains?
A B C D
Hub Repeater Switch Router
Answer: C — Switch. Switches create separate collision domains per port, but all ports on a switch
belong to the same broadcast domain unless VLANs are configured.
,2
4. Which protocol is used to resolve an IPv4 address to a MAC address?
A B C D
DNS DHCP ARP ICMP
Answer: C — ARP. Address Resolution Protocol maps a known IP address to its corresponding MAC
address on a local network.
5. What is the primary purpose of a subnet mask?
A B C D
To define which portion of an IP To assign MAC
To encrypt To monitor network
address is the network and addresses
data packets traffic for anomalies
which is the host dynamically
Answer: B — Subnet masks divide an IP address into network and host portions, allowing proper
routing and subnetting.
6. Which OSI layer is responsible for reliable data delivery, error detection, and retransmission?
A B C D
Network Layer Data Link Layer Transport Layer Physical Layer
Answer: C — Transport Layer. Layer 4 manages end-to-end communication, error recovery, flow
control, and segmentation. TCP operates at this layer.
7. Which component converts digital signals into analog signals for transmission over traditional phone
lines?
A B C D
Router Switch Modem Repeater
Answer: C — Modem. A modem (modulator-demodulator) converts digital data to analog for
transmission over analog lines (like POTS) and back again.
,3
8. What is the primary purpose of multiplexing?
A B C D
Error Combining multiple signals into one Increasing signal Encrypting
correction channel strength data
Answer: B — Multiplexing allows multiple data streams to share a single transmission medium,
improving efficiency. Common methods include TDM and FDM.
9. Which transmission medium provides the highest bandwidth and lowest signal loss?
A B C D
Coaxial cable Twisted pair Fiber-optic cable Microwave
Answer: C — Fiber-optic cable. Fiber transmits data as light pulses, offering extremely high bandwidth
and minimal interference.
10. What does latency measure?
A B C D
Error rate Bandwidth Delay in transmission Signal strength
Answer: C — Latency is the time delay between sending and receiving data.
11. Which layer of the OSI model is responsible for routing packets across different networks?
A B C D
Physical Data Link Network Transport
Answer: C — Network Layer. Routers operate at Layer 3 to determine optimal paths and forward
packets between different networks.
, 4
12. Which OSI layer defines the mechanical, electrical, and procedural characteristics to establish,
maintain, and deactivate physical links?
A B C D
Data Link Layer Physical Layer Network Layer Transport Layer
Answer: B — Physical Layer. Layer 1 deals with hardware transmission technologies such as cabling,
connectors, and signal specifications.
13. Which OSI layer is responsible for encryption, decryption, and data compression?
A B C D
Session Layer Presentation Layer Application Layer Transport Layer
Answer: B — Presentation Layer. Layer 6 translates data formats, encrypts/decrypts, and compresses
data for application layer use.
14. Which protocol operates at the Network layer and is responsible for logical addressing and routing?
A B C D
TCP UDP IP Ethernet
Answer: C — IP (Internet Protocol) operates at Layer 3 and handles logical addressing (IP addresses)
and packet routing.
15. Which of the following is a connection-oriented protocol that guarantees delivery?
A B C D
UDP IP TCP ICMP
Answer: C — TCP (Transmission Control Protocol) uses acknowledgments, sequencing, and flow
control to ensure reliable data delivery.
