OSI Model Flashcards
Learn the OSI model.
What does OSI stand for in OSI Model?
Open Systems Interconnection.
What does the OSI provide?
A standard for different computer systems to be able to communicate with each other.
What are the seven layers of the OSI?
- Application Layer.
- Presentation Layer.
- Session Layer.
- Transport Layer.
- Network Layer.
- Datalink Layer.
- Physical Layer.
What is the application layer (7) of OSI?
Human computer interaction layer, where applications can access network services.
What does the presentation layer (6) of OSI do?
Ensures that data is in a usable format and is where data encryption occurs.
What does the session layer (5) of OSI do?
Maintains connections and is responsible for controlling ports and sessions.
What does the transport layer (4) of OSI do?
Transmits data using transmission protocols including TCP and UDP.
What does the network layer (3) of OSI do?
Decides which physical path the data will take.
What doe the datalink layer (2) of OSI do?
Defines the format of data on the network.
What does the physical layer (1) of OSI do?
Transmits raw bit stream over the physical medium.
How is the OSI model useful?
Troubleshooting network problems.
What is the only layer that directly interacts with data form users in the OSI?
Application layer.
What is the application layer responsible for in the OSI?
Protocols and data manipulation that the application software relies on to present meaningful data to the user.
What are examples of application layer protocols?
HTTP, SMTP
What is the presentation layer responsible for in the OSI?
Translation, encryption, and compression of data.
What is the session layer responsible for in the OSI?
Opening and closing communication between two devices.
How can the session layer help with synchronization of data transfer between devices?
Using checkpoints so in case of disconnect or crash, transfer can resume at checkpoint.
What is the transport layer responsible for in the OSI?
End-to-end communication between two devices as well as flow control and error control.
What does the transport layer do to the data before moving it from the session layer to the network layer?
Breaks it up into chunks called sessions.
What is the transport layer on the receiving device responsible for?
Reassembling the segments into data the session layer can consume.
What does flow control determine in the transport layer?
Optimal speed of transmission to ensure that a sender with a fast connection doesn’t overwhelm a receiver with a slow connection.
What does error control do in the transport layer?
Ensures that the data received is complete, and requests a retransmission if it isn’t.
What is the network layer responsible for in the OSI?
Facilitating data transfer between two different networks. Finding the best physical path for the data to reach its destination (routing).
When is the networking layer unnecessary?
When the two communicating devices are on the same network.
What does the network layer do on the senders device/
Breaks up segments from the transport layer into packets.
What does the network layer do on the receivers device?
Reassembles packets.
What is the datalink layer responsible for in the OSI?
Facilitating data transfer between two devices on the SAME network. Also, responsible for flow control and error control in intra-network communication.
What does the datalink layer do with packets from the network layer?
Brakes them into smaller pieces called frames.
What is the physical layer responsible for in OSI?
Converting data into bit streams (0s and 1s).
What is the physical equipment involved in the physical layer?
Switches and cables.
In the physical layer, what must both devices agree upon so that the 1s can be distinguished from the 0s on both devices?
The signal convention.
