CompTIA Network+ Certification (N10-003) Part 8

1. Which layer of the OSI reference model is responsible for session creation?

Transport

Session

Presentation

Application

The Session Layer of the OSI model is responsible for establishing, maintaining and breaking sessions.

Explanation

The Session Layer of the OSI model is responsible for establishing, maintaining and breaking sessions.

2. You are a working as a technician and your boss asks you to clarify the difference between routers and switches. You tell him that switches work at the Data Link Layer of the OSI model while routers work at the _____.

Physical layer

Data Link layer

Network layer

Application layer

The Network Layer of the OSI model is responsible for end-to-end delivery of data packets. This includes routing and can include packet filtering.

Explanation

The Network Layer of the OSI model is responsible for end-to-end delivery of data packets. This includes routing and can include packet filtering.

3. At which layer of the OSI reference model does a router operate?

Physical

Data Link

Network

Transport

The Network Layer of the OSI ensures that the data arrives at the correct destination. As such, it concerned with network addressing and routing. A router is responsible for routing and functions at the Network Layer.

Explanation

The Network Layer of the OSI ensures that the data arrives at the correct destination. As such, it concerned with network addressing and routing. A router is responsible for routing and functions at the Network Layer.

4. The MAC address f2:a1:23:bc:d3:41 consists of a manufacturer ID and a station ID. Which three bytes represents the manufacturer identifier, also known as the Organizationally Unique Identifer (OUI)?

F2:a1:23

A1:23:bc

23:bc:d3

Bc:d3:41

A MAC address consists of two parts: an Organizationally Unique Identifier (OUI) which is administered by the IEEE and uniquely identifies the manufacturer of the interface; and a device ID which identifies the interface. The first three sets of digits represents the OUI while the last three digits represents the device ID.

Explanation

A MAC address consists of two parts: an Organizationally Unique Identifier (OUI) which is administered by the IEEE and uniquely identifies the manufacturer of the interface; and a device ID which identifies the interface. The first three sets of digits represents the OUI while the last three digits represents the device ID.

5. Which of the following operate at the Network Layer?

Hubs

Routers

Switches

Wireless Access Points

Routers are responsible for the efficient routing of network traffic in an internetwork. As routing occurs at the Network Layer (Layer 3), routers are Layer 3 devices.

Explanation

Routers are responsible for the efficient routing of network traffic in an internetwork. As routing occurs at the Network Layer (Layer 3), routers are Layer 3 devices.

6. Which of the following operate at the Data Link Layer of the OSI?

Bridges, switches and wireless access points

Wireless access points and routers

Bridges, switches and routers

Network interface cards

Bridges, switches and wireless access points all operate at the Data Link Layer of the OSI which is Layer 2.

Explanation

Bridges, switches and wireless access points all operate at the Data Link Layer of the OSI which is Layer 2.

7. At which layer of the OSI reference model does routing occur?

Physical

Data Link

Network

Transport

The Network Layer of the OSI ensures that the data arrives at the correct destination. As such, it is concerned with network addressing and routing

Explanation

The Network Layer of the OSI ensures that the data arrives at the correct destination. As such, it is concerned with network addressing and routing

8. At which layer of the OSI reference model does a hub operate?

Physical

Data Link

Network

Transport

The Physical Layer of the OSI is concerned with the physical elements of the network. This includes the transmission medium, the physical topology, the voltage, signal direction and signal strength. Hubs merely retransmit data and thus operate at the Physical Layer (Layer 1) of the OSI reference model.

Explanation

The Physical Layer of the OSI is concerned with the physical elements of the network. This includes the transmission medium, the physical topology, the voltage, signal direction and signal strength. Hubs merely retransmit data and thus operate at the Physical Layer (Layer 1) of the OSI reference model.

9. Which of the following is responsible for resolving an IP address to a MAC address?

ARP

DNS

DHCP

WINS

The Address Resolution Protocol (ARP) resolves an IP address to the MAC address. The MAC address is a Data Link Layer address that is embedded in a ROM on the network device and is hard-coded to each network interface.

Explanation

The Address Resolution Protocol (ARP) resolves an IP address to the MAC address. The MAC address is a Data Link Layer address that is embedded in a ROM on the network device and is hard-coded to each network interface.

10. Which of the following operate at the Physical Layer?

Hubs

Routers

Switches

Wireless Access Points

Hubs merely retransmit data and thus operate at the Physical Layer (Layer 1) of the OSI reference model.

Explanation

Hubs merely retransmit data and thus operate at the Physical Layer (Layer 1) of the OSI reference model.

11. A trainee asks you what the OSI layer where digital data is converted into electronic signals to be put on a wire is called. How do you answer?

The Physical Layer

The Transport Layer

The Data Link Layer

The Presentation Layer

The Physical Layer of the OSI is concerned with the physical elements of the network. This includes the transmission medium and physical topology. One of the functions of the Physical layer is signal encoding, which is the translation of data into electronic signals that can be transmitted on a transmission medium.

Explanation

The Physical Layer of the OSI is concerned with the physical elements of the network. This includes the transmission medium and physical topology. One of the functions of the Physical layer is signal encoding, which is the translation of data into electronic signals that can be transmitted on a transmission medium.

12. Which of the following operate at the upper three layers of the OSI model?

Routers

Switches

Gateways

Wireless Access Points

A gateway is used to connect two dissimilar networks. It operates at all the layers of the OSI.

Explanation

A gateway is used to connect two dissimilar networks. It operates at all the layers of the OSI.

13. Which layer of the OSI reference model is concerned with network addressing?

Physical

Data Link

Network

Transport

The Network Layer of the OSI ensures that the data arrives at the correct destination. As such, it is concerned with network addressing and routing.

Explanation

The Network Layer of the OSI ensures that the data arrives at the correct destination. As such, it is concerned with network addressing and routing.

14. Which of the following statements regarding the OSI reference model is false?

The Network Layer of the OSI is responsible for the establishment, maintenance and breaking of sessions

The Transport Layer of the OSI is concerned about the structure of messages and the validity of transmissions

The Network Layer of the OSI ensures that the data arrives at the correct destination. As such, it is concerned with network addressing and routing, not session management. The Session Layer is concerned with the establishment, maintenance and breaking of sessions.

Explanation

The Network Layer of the OSI ensures that the data arrives at the correct destination. As such, it is concerned with network addressing and routing, not session management. The Session Layer is concerned with the establishment, maintenance and breaking of sessions.

15. The MAC address f2:a1:23:bc:d3:41 consists of a manufacturer ID and a station ID. Which three bytes represents the station identifier?

F2:a1:23

A1:23:bc

23:bc:d3

Bc:d3:41

A MAC address consists of two parts: an Organizationally Unique Identifier (OUI) which is administered by the IEEE and uniquely identifies the manufacturer of the interface; and a device ID which identifies the interface. The first three sets of digits represents the OUI while the last three digits represents the device ID.

Explanation

A MAC address consists of two parts: an Organizationally Unique Identifier (OUI) which is administered by the IEEE and uniquely identifies the manufacturer of the interface; and a device ID which identifies the interface. The first three sets of digits represents the OUI while the last three digits represents the device ID.

16. Which of the following statements regarding the OSI reference model is true?

The Session Layer of the OSI model is responsible for establishing, maintaining and breaking sessions

The Presentation Layer of the OSI model defines the choice of protocols, provides error recovery and flow control

The Session Layer of the OSI model is responsible for establishing, maintaining and breaking sessions.

Explanation

The Session Layer of the OSI model is responsible for establishing, maintaining and breaking sessions.

17. At which layer of the OSI reference model does data encryption occur?

Transport

Session

Presentation

Application

The Presentation Layer of the OSI model converts the data from the lower layers into a format that the upper-layer processes require. In addition, the Presentation Layer also provides encryption, data compression and character-set translation which is also called code conversion.

Explanation

The Presentation Layer of the OSI model converts the data from the lower layers into a format that the upper-layer processes require. In addition, the Presentation Layer also provides encryption, data compression and character-set translation which is also called code conversion.

18. At which layer of the OSI reference model does character-set translation occur?

Transport

Session

Presentation

Application

The Presentation Layer of the OSI model converts the data from the lower layers into a format that the upper-layer processes require. In addition, the Presentation Layer also provides encryption, data compression and character-set translation which is also called code conversion.

Explanation

The Presentation Layer of the OSI model converts the data from the lower layers into a format that the upper-layer processes require. In addition, the Presentation Layer also provides encryption, data compression and character-set translation which is also called code conversion.

19. You need a networking device that operates at the three uppermost layers of the OSI model and that can connect networks with different architectures. Which of the following would accomplish this?

Router

Firewall

Modem

Gateway

A gateway is used to connect two dissimilar networks. It operates at all the layers of the OSI.

Explanation

A gateway is used to connect two dissimilar networks. It operates at all the layers of the OSI.

20. A developer asks you which of the OSI layers that is responsible for translating from application to network, formatting and code conversations. How would you answer?

The Transport Layer

The Data Link Layer

The Application Layer

The Presentation Layer

The Presentation Layer of the OSI model converts the data from the lower layers into a format that the upper-layer processes require. In addition, the Presentation Layer also provides encryption, data compression and character-set translation which is also called code conversion.

Explanation

The Presentation Layer of the OSI model converts the data from the lower layers into a format that the upper-layer processes require. In addition, the Presentation Layer also provides encryption, data compression and character-set translation which is also called code conversion.

21. You are asked to identify two devices classified as Layer 2. Which would you select?

Switches and routers

Switches and bridges

Switches and NICs

Hubs and switches

Switches and bridges operate at the Data Link Layer of the OSI and are thus Layer 2 devices.

Explanation

Switches and bridges operate at the Data Link Layer of the OSI and are thus Layer 2 devices.

22. At which layer of the OSI reference model does data compression occur?

Transport

Session

Presentation

Application

The Presentation Layer of the OSI model converts the data from the lower layers into a format that the upper-layer processes require. In addition, the Presentation Layer also provides encryption, data compression and character-set translation which is also called code conversion.

Explanation

The Presentation Layer of the OSI model converts the data from the lower layers into a format that the upper-layer processes require. In addition, the Presentation Layer also provides encryption, data compression and character-set translation which is also called code conversion.

23. At which layers of the OSI reference model does packet filtering occur?

Physical and Data Link

Data Link and Network

Data Link and Transport

Network and Transport

The Network Layer of the OSI model is responsible for end-to-end delivery of data packets. This includes routing and can include packet filtering. The Transport Layer of the OSI model is responsible for several functions, including the choice of protocols, error recovery and flow control and reordering of the incoming data stream. Through flow control, packet filtering can be implemented

Explanation

The Network Layer of the OSI model is responsible for end-to-end delivery of data packets. This includes routing and can include packet filtering. The Transport Layer of the OSI model is responsible for several functions, including the choice of protocols, error recovery and flow control and reordering of the incoming data stream. Through flow control, packet filtering can be implemented

24. At which layer of the OSI reference model does error recovery and flow control occur?

Transport

Session

Presentation

Application

The Transport Layer of the OSI model defines several functions, including the choice of protocols, error recovery and flow control

Explanation

The Transport Layer of the OSI model defines several functions, including the choice of protocols, error recovery and flow control

25. You are working as a senior network technician. One of your trainees asks you to clarify at which Open Systems Interconnect (OSI) layers a packet filtering firewall operates. How do you answer?

Network and Data Link

Network and Transport

Transport and Session

Physical and Data Link

The Network Layer of the OSI model is responsible for end-to-end delivery of data packets. This includes routing and can include packet filtering. The Transport Layer of the OSI model is responsible for several functions including the choice of protocols, error recovery and flow control and the reordering of the incoming data stream. Through flow control, packet filtering can be implemented.

Explanation

The Network Layer of the OSI model is responsible for end-to-end delivery of data packets. This includes routing and can include packet filtering. The Transport Layer of the OSI model is responsible for several functions including the choice of protocols, error recovery and flow control and the reordering of the incoming data stream. Through flow control, packet filtering can be implemented.

26. Which layer of the OSI reference model is responsible for signal encoding?

Physical

Data Link

Network

Transport

The Physical Layer of the OSI is concerned with the physical elements of the network. This includes the transmission medium and physical topology. One of the functions of the Physical Layer is signal encoding, which is the translation of data into electronic signals that can be transmitted on a transmission medium.

Explanation

The Physical Layer of the OSI is concerned with the physical elements of the network. This includes the transmission medium and physical topology. One of the functions of the Physical Layer is signal encoding, which is the translation of data into electronic signals that can be transmitted on a transmission medium.

27. Which layer of the OSI reference model defines data delivery across an individual link?

Physical

Data Link

Network

Transport

The Data Link Layer of the OSI is concerned with getting data across a particular link or medium and defines delivery across an individual link

Explanation

The Data Link Layer of the OSI is concerned with getting data across a particular link or medium and defines delivery across an individual link

28. Which of the following operate at the Data Link Layer? (choose all that apply)

Hubs

Routers

Switches

Wireless Access Points

Both switches and Wireless Access Points (WAPs) use MAC addresses to filter traffic. As MAC addressing is performed at the Data Link layer (Layer 2), both switches and WAPs are Layer 2 devices.

Explanation

Both switches and Wireless Access Points (WAPs) use MAC addresses to filter traffic. As MAC addressing is performed at the Data Link layer (Layer 2), both switches and WAPs are Layer 2 devices.

Submit

29. Which of the following do not operate at Layer 2 of the OSI? (choose all that apply)

Bridges

Routers

Switches

Wireless Access Points

Network Interface Cards

Routers operate at Layer 3 while Network Interface Cards operate at Layer 1.

Explanation

Routers operate at Layer 3 while Network Interface Cards operate at Layer 1.

Submit

30. Which of the following is responsible for resolving MAC address to an IP address

ARP

DNS

RARP

WINS

Reverse ARP resolves a MAC address to an IP address. The MAC address is a Data Link Layer address that is embedded in a ROM on the network device and is hard-coded to each network interface.

Explanation

Reverse ARP resolves a MAC address to an IP address. The MAC address is a Data Link Layer address that is embedded in a ROM on the network device and is hard-coded to each network interface.