|
In this section, you’ll complete the following labs to make sure you understand the information and concepts contained within them:
Lab 1.1: The OSI Reference Model
Lab 1.2: Defining the OSI Layers and Devices
Lab 1.3: Identifying Collision and Broadcast Domains
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? |
|
2. | Which layer is responsible for converting data packets from the Data Link layer into electrical signals? |
|
3. | At which layer is routing implemented, enabling connections and path selection between two end systems? |
|
4. | Which layer defines how data is formatted, presented, encoded, and converted for use on the network? |
|
5. | Which layer is responsible for creating, managing, and terminating sessions between applications? |
|
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? |
|
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? |
|
8. | Which layer provides logical addressing that routers use for path determination? |
|
9. | Which layer specifies voltage, wire speed, and pinout cables and moves bits between devices? |
|
10. | Which layer combines bits into bytes and bytes into frames, uses MAC addressing, and provides error detection? |
|
11. | Which layer is responsible for keeping the data from different applications separate on the network? |
|
12. | Which layer is represented by frames? |
|
13. | Which layer is represented by segments? |
|
14. | Which layer is represented by packets? |
|
15. | Which layer is represented by bits? |
|
16. | Put the following in order of encapsulation:
|
|
17. | Which layer segments and reassembles data into a data stream? |
|
18. | Which layer provides the physical transmission of the data and handles error notification, network topology, and flow control? |
|
19. | Which layer manages device addressing, tracks the location of devices on the network, and determines the best way to move data? |
|
20. | What is the bit length and expression form of a MAC address? |
|
Answers
1. | The Application layer is responsible for finding the network resources broadcast from a server and adding flow control and error control (if the application developer chooses). |
2. | The Physical layer takes frames from the Data Link layer and encodes the 1s and 0s into a digital signal from transmission on the network medium. |
3. | The Network layer provides routing through an internetwork and through logical addressing. |
4. | The Presentation layer makes sure that data is in a readable format for the Application layer. |
5. | The Session layer sets up, maintains, and terminates sessions between applications. |
6. | PDUs at the Data Link layer are called frames. As soon as you see “frame” in a question, you know the answer. |
7. | The Transport layer uses virtual circuits to create a reliable connection between two hosts. |
8. | The Network layer provides logical addressing, typically IP addressing and routing. |
9. | The Physical layer is responsible for the electrical and mechanical connections between devices. |
10. | The Data Link layer is responsible for framing data packets. |
11. | The Session layer creates sessions between different hosts’ applications. |
12. | The Data Link layer frames packets received from the Network layer. |
13. | The Transport layer segments user data. |
14. | The Network layer creates packets out of segments handed down from the Transport layer. |
15. | The Physical layer is responsible for transporting 1s and 0s in a digital signal. |
16. | Segments, packets, frames, bits. |
17. | The Transport layer segments and reassembles data into a data stream. |
18. | The Data Link layer provides the physical transmission of the data and handles error notification, network topology, and flow control. |
19. | The Network layer manages device addressing, tracks the location of devices on the network, and determines the best way to move the data. |
20. | 48 bits (6 bytes) expressed as a hexadecimal number is the bit length and expression form of a MAC address. |
Fill in the blanks with the appropriate layer of the OSI reference model or hub, switch, or router device.
Description | Device or OSI Layer |
---|---|
This device sends and receives information about theNetwork layer. | |
This layer creates a virtual circuit for transmitting between two end stations. | |
This layer uses service access points. | |
This device uses hardware addresses to filter a network. | |
Ethernet is defined at these layers. | |
This layer supports flow control and sequencing. | |
This device can measure the distance to a remote network. | |
Logical addressing is used at this layer. | |
Hardware addresses are defined at this layer. | |
This device creates one big collision domain andonelarge broadcast domain. | |
This device creates many smaller collision domains, but the network is still one large broadcast domain. | |
This device breaks up collision domains and broadcast domains. |
Answers to Lab 1.2
Description | Device or OSI Layer |
---|---|
This device sends and receives information about the Network layer. | router |
This layer can create a virtual circuit for transmitting between two end stations. | Transport layer |
This layer uses service access points. | Data Link layer (LLC sublayer) |
This device uses hardware addresses to filter a network. | bridge or switch |
Ethernet is defined at these layers. | Data Link and Physical layers |
This layer supports flow control and sequencing. | Transport layer |
This device can measure the distance to a remote network. | router |
Logical addressing is used at this layer. | Network layer |
Hardware addresses are defined at this layer. | Data Link layer (MAC sublayer) |
This device creates one big collision domain and one large broadcast domain. | hub |
This device creates many smaller collision domains but the network is still one large broadcast domain. | switch or bridge |
This device breaks up collision domains and broadcast domains. | router |
1. | In Figure 1.24, identify the number of collision domains and broadcast domains in each specified device. Each device is represented by a letter.
|
|
Answers
1. | Hub: One collision domain, one broadcast domain Bridge: Two collision domains, one broadcast domain Switch: Four collision domains, one broadcast domain Router: Three collision domains, three broadcast domains |
|