WGU C480
WGU C480 Network+ N10-009 Ultimate Exam Cram: 200
Expert-Designed Questions & Rationales on OSI Model,
TCP/IP, IPv4/IPv6 Subnetting, Modern SDN, SASE, Zero-
Trust, and Network Troubleshooting (2026 Edition)
Domain 1: OSI & TCP/IP Models (Questions 1–15)
1. A network administrator is troubleshooting a slow network and notices excessive collisions. At
which OSI layer would collisions be detected?
• A) Network
• B) Transport
• C) Data Link
• D) Physical
Answer: C – Collisions occur at Layer 2 (Data Link) because this layer controls access to the
physical medium via MAC addresses and CSMA/CD. However, note that collisions are
physically detected at Layer 1, but the logic for handling them resides at Layer 2.
2. Which layer of the OSI model is responsible for data encryption and compression?
• A) Session
• B) Transport
• C) Presentation
• D) Application
Answer: C – The Presentation layer (Layer 6) handles formatting, encryption, and
compression so that the Application layer receives data in a readable format.
3. A router receives a packet and needs to forward it to a destination on a different network.
Which address does the router primarily use to make this decision?
• A) MAC address
• B) IP address
• C) Port number
• D) Frame header
Answer: B – Routers operate at Layer 3 (Network) and use logical IP addresses to determine
the best path for forwarding packets.
4. In the TCP/IP model, which layer is responsible for logical addressing and routing?
• A) Application
• B) Transport
• C) Internet
, WGU C480
• D) Network Access
Answer: C – In the 4-layer TCP/IP model, the Internet layer equates to the OSI Network layer
and handles logical addressing (IP) and routing.
5. Which OSI layer ensures that a data stream is error-free, sequenced, and reliably delivered?
• A) Network
• B) Data Link
• C) Transport
• D) Physical
Answer: C – The Transport layer (Layer 4) provides end-to-end communication. TCP handles
segmentation, sequencing, and error recovery to ensure reliable delivery.
6. A switch learns which MAC address is associated with a specific port. At which OSI layer does
this switch operate?
• A) Physical
• B) Data Link
• C) Network
• D) Session
Answer: B – Switches are Layer 2 devices. They build a MAC address table to make
forwarding decisions based on the destination MAC address found in the frame header.
7. Which protocol is mapped to the Network Access layer of the TCP/IP model?
• A) TCP
• B) IP
• C) Ethernet
• D) HTTP
Answer: C – The Network Access layer (sometimes called Link/Physical) includes protocols
like Ethernet, Wi-Fi, and PPP that operate on the physical medium.
8. A web browser sends a request to a server. At which OSI layer does the HTTP protocol operate?
• A) Presentation
• B) Session
• C) Application
• D) Transport
Answer: C – HTTP is a user-facing protocol that provides network services to applications; it
resides at the Application layer (Layer 7).
9. Which of the following is a function of the Session layer?
• A) Routing
• B) Error correction
, WGU C480
• C) Dialog control (establishing/terminating sessions)
• D) Bit synchronization
Answer: C – The Session layer (Layer 5) establishes, manages, and terminates sessions
(dialogues) between two communicating hosts.
10. How many layers are in the modern TCP/IP model used by CompTIA Network+ N10-009?
• A) 4
• B) 5
• C) 7
• D) 3
Answer: B – The updated N10-009 exam emphasizes a 5-layer TCP/IP model (Application,
Transport, Internet, Data Link, Physical) to better align with modern networking concepts.
11. A network technician is troubleshooting a faulty network interface card (NIC). Which OSI layer
is physically failing?
• A) Data Link
• B) Physical
• C) Network
• D) Transport
Answer: B – The Physical layer (Layer 1) defines the hardware specifications, including
cables, connectors, and NICs, and transmits the raw bitstream.
12. Which OSI layer adds a trailer for error checking using a Frame Check Sequence (FCS)?
• A) Network
• B) Transport
• C) Data Link
• D) Physical
Answer: C – The Data Link layer (Layer 2) encapsulates the packet into a frame and adds a
trailer containing the FCS (like CRC) for error detection.
13. In the OSI model, which layer is responsible for determining if enough network resources are
available for a communication session?
• A) Application
• B) Session
• C) Transport
• D) Network
Answer: B – The Session layer (Layer 5) establishes and maintains communication channels.
Part of this setup involves checking availability, though actual resource allocation might
involve upper layers.
, WGU C480
14. Which statement is true regarding the OSI and TCP/IP models?
• A) The OSI model is older and less flexible than TCP/IP
• B) The TCP/IP model combines the OSI Presentation and Session layers into the Application
layer
• C) The OSI model has 5 layers
• D) TCP/IP is a theoretical model while OSI is the practical standard
Answer: B – In the 5-layer TCP/IP model, the Application layer encompasses the functions of
OSI Layers 5, 6, and 7.
15. A proxy server operates at which OSI layer?
• A) Network
• B) Transport
• C) Application
• D) Presentation
Answer: C – A proxy server acts as an intermediary for requests from clients seeking
resources. It operates at the Application layer because it interprets the application-specific
data (like HTTP headers).
Domain 2: IP Addressing & Binary Conversion (Questions 16–30)
16. What is the decimal equivalent of the binary number 11001010?
• A) 200
• B) 202
• C) 210
• D) 250
Answer: B – 128 + 64 + 0 + 0 + 8 + 0 + 2 + 0 = 202.
17. Convert the decimal number 192 into binary.
• A) 11000000
• B) 11100000
• C) 10101000
• D) 10000001
Answer: A – 128 + 64 = 192, so the bits for 128 and 64 are 1, and the rest are 0: 11000000.
18. Which class of IP address uses the first octet range of 192–223?
• A) Class A
• B) Class B
• C) Class C
WGU C480 Network+ N10-009 Ultimate Exam Cram: 200
Expert-Designed Questions & Rationales on OSI Model,
TCP/IP, IPv4/IPv6 Subnetting, Modern SDN, SASE, Zero-
Trust, and Network Troubleshooting (2026 Edition)
Domain 1: OSI & TCP/IP Models (Questions 1–15)
1. A network administrator is troubleshooting a slow network and notices excessive collisions. At
which OSI layer would collisions be detected?
• A) Network
• B) Transport
• C) Data Link
• D) Physical
Answer: C – Collisions occur at Layer 2 (Data Link) because this layer controls access to the
physical medium via MAC addresses and CSMA/CD. However, note that collisions are
physically detected at Layer 1, but the logic for handling them resides at Layer 2.
2. Which layer of the OSI model is responsible for data encryption and compression?
• A) Session
• B) Transport
• C) Presentation
• D) Application
Answer: C – The Presentation layer (Layer 6) handles formatting, encryption, and
compression so that the Application layer receives data in a readable format.
3. A router receives a packet and needs to forward it to a destination on a different network.
Which address does the router primarily use to make this decision?
• A) MAC address
• B) IP address
• C) Port number
• D) Frame header
Answer: B – Routers operate at Layer 3 (Network) and use logical IP addresses to determine
the best path for forwarding packets.
4. In the TCP/IP model, which layer is responsible for logical addressing and routing?
• A) Application
• B) Transport
• C) Internet
, WGU C480
• D) Network Access
Answer: C – In the 4-layer TCP/IP model, the Internet layer equates to the OSI Network layer
and handles logical addressing (IP) and routing.
5. Which OSI layer ensures that a data stream is error-free, sequenced, and reliably delivered?
• A) Network
• B) Data Link
• C) Transport
• D) Physical
Answer: C – The Transport layer (Layer 4) provides end-to-end communication. TCP handles
segmentation, sequencing, and error recovery to ensure reliable delivery.
6. A switch learns which MAC address is associated with a specific port. At which OSI layer does
this switch operate?
• A) Physical
• B) Data Link
• C) Network
• D) Session
Answer: B – Switches are Layer 2 devices. They build a MAC address table to make
forwarding decisions based on the destination MAC address found in the frame header.
7. Which protocol is mapped to the Network Access layer of the TCP/IP model?
• A) TCP
• B) IP
• C) Ethernet
• D) HTTP
Answer: C – The Network Access layer (sometimes called Link/Physical) includes protocols
like Ethernet, Wi-Fi, and PPP that operate on the physical medium.
8. A web browser sends a request to a server. At which OSI layer does the HTTP protocol operate?
• A) Presentation
• B) Session
• C) Application
• D) Transport
Answer: C – HTTP is a user-facing protocol that provides network services to applications; it
resides at the Application layer (Layer 7).
9. Which of the following is a function of the Session layer?
• A) Routing
• B) Error correction
, WGU C480
• C) Dialog control (establishing/terminating sessions)
• D) Bit synchronization
Answer: C – The Session layer (Layer 5) establishes, manages, and terminates sessions
(dialogues) between two communicating hosts.
10. How many layers are in the modern TCP/IP model used by CompTIA Network+ N10-009?
• A) 4
• B) 5
• C) 7
• D) 3
Answer: B – The updated N10-009 exam emphasizes a 5-layer TCP/IP model (Application,
Transport, Internet, Data Link, Physical) to better align with modern networking concepts.
11. A network technician is troubleshooting a faulty network interface card (NIC). Which OSI layer
is physically failing?
• A) Data Link
• B) Physical
• C) Network
• D) Transport
Answer: B – The Physical layer (Layer 1) defines the hardware specifications, including
cables, connectors, and NICs, and transmits the raw bitstream.
12. Which OSI layer adds a trailer for error checking using a Frame Check Sequence (FCS)?
• A) Network
• B) Transport
• C) Data Link
• D) Physical
Answer: C – The Data Link layer (Layer 2) encapsulates the packet into a frame and adds a
trailer containing the FCS (like CRC) for error detection.
13. In the OSI model, which layer is responsible for determining if enough network resources are
available for a communication session?
• A) Application
• B) Session
• C) Transport
• D) Network
Answer: B – The Session layer (Layer 5) establishes and maintains communication channels.
Part of this setup involves checking availability, though actual resource allocation might
involve upper layers.
, WGU C480
14. Which statement is true regarding the OSI and TCP/IP models?
• A) The OSI model is older and less flexible than TCP/IP
• B) The TCP/IP model combines the OSI Presentation and Session layers into the Application
layer
• C) The OSI model has 5 layers
• D) TCP/IP is a theoretical model while OSI is the practical standard
Answer: B – In the 5-layer TCP/IP model, the Application layer encompasses the functions of
OSI Layers 5, 6, and 7.
15. A proxy server operates at which OSI layer?
• A) Network
• B) Transport
• C) Application
• D) Presentation
Answer: C – A proxy server acts as an intermediary for requests from clients seeking
resources. It operates at the Application layer because it interprets the application-specific
data (like HTTP headers).
Domain 2: IP Addressing & Binary Conversion (Questions 16–30)
16. What is the decimal equivalent of the binary number 11001010?
• A) 200
• B) 202
• C) 210
• D) 250
Answer: B – 128 + 64 + 0 + 0 + 8 + 0 + 2 + 0 = 202.
17. Convert the decimal number 192 into binary.
• A) 11000000
• B) 11100000
• C) 10101000
• D) 10000001
Answer: A – 128 + 64 = 192, so the bits for 128 and 64 are 1, and the rest are 0: 11000000.
18. Which class of IP address uses the first octet range of 192–223?
• A) Class A
• B) Class B
• C) Class C
