CCNA Exercise Lab 1

Lab 1.1: OSI Questions

Answer the following questions about the OSI model:

1. Which layer chooses and determines the availability of communicating partners, along with the resources necessary to make the connection; coordinates partnering applications; and forms a consensus on procedures for controlling data integrity and error recovery?

Ans – Session Layer

2. Which layer is responsible for converting data packets from the Data Link layer into electrical signals?

Ans – Physical Layer

3. At which layer is routing implemented, enabling connections and path selection between two end systems?

Ans – Network Layer

4. Which layer defines how data is formatted, presented, encoded, and converted for use on the network?

Ans – Transport Layer

5. Which layer is responsible for creating, managing, and terminating sessions between applications?

Ans – Session Layer

6. Which layer ensures the trustworthy transmission of data across a physical link and is primarily concerned with physical addressing, line discipline, network topology, error notification, ordered delivery of frames, and flow control?

Ans – Transport Layer

7. Which layer is used for reliable communication between end nodes over the network and provides mechanisms for establishing, maintaining, and terminating virtual circuits; transport-fault detection and recovery; and controlling the flow of information?

Ans – Transport Layer

8. Which layer provides logical addressing that routers will use for path determination?

Ans – Data Link layer

9. Which layer specifies voltage, wire speed, and pin-out cables and moves bits between devices?

Ans – Physical Layer

10. Which layer combines bits into bytes and bytes into frames, uses MAC addressing, and provides error detection?

Ans – Data-Link Layer

11. Which layer is responsible for keeping different applications’ data separate on the network?

Ans – Presentation Layer

12. Which layer is represented by frames?

Ans – Data Link Layer

13. Which layer is represented by segments?

Ans – Transport Layer

14. Which layer is represented by packets?

Ans – Network layer

15. Which layer is represented by bits?

Ans – Physical Layer

16. Put the following in order of encapsulation:

Packets
Frames
Bits
Segments

Answer:

Segments
Packets
Frames
Bits

17. Put the following in order of de-encapsulation:

Packets
Frames
Bits
Segments

Answer:

Bits
Frames
Packets
Segments

Lab 1.2: Defining the OSI Layers and Devices

Fill in the blanks with the appropriate layer of the OSI or hub, switch, or router device.

Description	Device or OSI Layer
Logical port numbers are used at this layer.	Ans- Application Layer
This device sends and receives information about the Network layer.	Ans- Router
This layer creates a virtual circuit before transmitting between two end stations.	Ans- Session layer
This layer uses service access points.	Ans- Physical Layer
This device uses hardware addresses to filter a network.	Ans- Switch or Bridge
Ethernet is defined at these layers.	Ans- Data Link Layer
This layer supports flow control and sequencing.	Ans- Transport Layer
This device can measure the distance to a remote network.	Ans- Router
Logical addressing is used at this layer.	Ans- Network Layer
Hardware addresses are defined at this layer.	Ans- Data Link Layer
This device creates one big collision domain and one large broadcast domain.	Ans- Hub
This device creates many smaller collision domains, but the network is still one large broadcast domain.	Ans- Switch
This device breaks up collision domains and broadcast domains.	Ans- Router

Lab 1.3: Identifying Collision and Broadcast Domains

In Figure, identify the amount of collision domains and broadcast domains in each network.

Identifying the amount of collision and broadcast domains

Collision domains: Broadcast domains:

A - 0, 0
B - 2, 1
C - 4, 1
D - 2, 4

Review Questions

Which Cisco layer is responsible for breaking up collision domains?
- Physical
- Access
- Core
- Network
- Distribution
- Data Link
- Ans- A

PDUs at the Network layer of the OSI are called what?

Core
Frames
Packets
Segments
Access
Distribution
Transport
Ans- C

At which Cisco layer would broadcast domains be defined?

Core
Network
Physical
Distribution
Access
Transport
Ans- B

PDUs at the Data Link layer is named what?

Frames
Packets
Datagrams
Transports
Segments
Bits
Ans- A

Segmentation of a data stream happens at which layer of the OSI model?

Physical
Data Link
Network
Transport
Distribution
Access
Ans- D

For which of the following would you not need to provide a crossover cable?

Connecting uplinks between switches
Connecting routers to switches
Connecting hub to hub
Connecting hubs to switches
Ans- Hub to Hub

What does the Data Link layer use to find hosts on a local network?

Logical network addresses
Port numbers
Hardware addresses
Default gateways
Ans- C

How is a crossover cabled?

The pins 1–8 are completely opposite on the other
It has the pins 1–8 cabled the same on the other
Pin 1 on one side connects to pin 3 on the other side and pin 2 connects to pin 6 on the other
Pin 2 on one side connects to pin 3 on the other side, and pin 1 connects to pin 6 on the other
Ans- C

Where are routers defined in the OSI model?

Physical
Transport
Data Link
Network
Ans- D

At which layer of the OSI are 1s and 0s converted to a digital signal?

Physical
Transport
Data Link
Network
Ans- A

Bridges are defined at what layer of the OSI model?

Physical
Transport
Data Link
Network
Ans- C

What Cisco layer provides segmentation of contention networks?

Access
Physical
Network
Distribution
Core
Transport
Data Link
Ans- F

What is used at the Transport layer to stop a receiving host’s buffer from overflowing?

Segmentation
Packets
Acknowledgments
Flow control
PDUs
Ans- A

Which layer of the OSI provides a translation of data?

Application
Presentation
Session
Transport
Data Link
Ans- A

Routers can provide which of the following functions? (Choose all that )

The breakup of collision domains
The breakup of broadcast domains
Logical network addressing
Physical address filtering of the local network
Ans- B,C,D

Routers are typically used at which layer of the Cisco three-layer model?

Access
Core
Network
Data Link
Distribution
Ans- C

How many bits define a hardware address?

6 bits
16 bits
46 bits
48 bits
Ans- D

Which of the following is not an advantage of a layer model?

Dividing the complex network operation into a more manageable layer approach
Allowing changes to occur in one layer without having to change all layers
Allowing changes to occur in all layers without having to change one layer
Defining a standard interface for the “plug-and-play” multivendor integration
Ans- A

Which three options use twisted-pair copper wiring?

100BaseFX
100BaseTX
100VG-AnyLAN
10BaseT
100BaseSX
Ans- B,D,E

What does the “Base” indicate in 10BaseT?

Backbone wiring that uses many digital signals at the same time in one
Baseband wiring that uses many digital signals at the same time in one
Backbone wiring that uses only one digital signal at a time in the
Baseband wiring that uses only one digital signal at a time in the
Ans- D