Networking OSI Model Flashcards
What does OSI stand for?
Open Systems Interconnection
How many Layers in the OSI Model?
7 Layers
Layer 1 is called
Physical Layer
Layer 2 is called
Data Link Layer
Layer 3 is called
Network Layer
Layer 6 is called
Presentation Layer
Layer 4 is called
Transport Layer
Layer 5 is called
Session Layer
Layer 7 is called
Application Layer
- How many layers are known as Media Layers?
- What are they?
3 Layers
- Layer 1 - Physical
- Layer 2 - Data Link
- Layer 3 - Network
How many layers are known as Host Layers and what are they?
4 Layers
Layer 4 - Transport
Layer 5 - Session
Layer 6 - Presentation
Layer 7 - Application
Layer 1 is composed of…
Unintelligent Devices such as Network Cables, Wireless Signals (WiFi), Network Hubs, Converters, Modem
What is the purpose of Layer 2?
Device Examples
Allows devices to connect to Networks.
Networking Switch, NICs, Access Points
What is the purpose of Layer 3?
Logical Addressing. Ensuring that the data arrives to the correct place.
What is the purpose of Layer 4?
Ensures that ALL Data is sent. It doesn’t care WHERE, just that it all gets there and correctly.
What is the purpose of Layer 5?
Allows for Multiple Access to the same destination.
What is the purpose of Layer 6?
What are some features?
Helps with the look and feel of the data.
Compression, Encryption, Language presentation
What is the purpose of Layer 7?
Handles Application services. Mainly Protocols such as HTTPS, SMB, SMTP etc.
What are the 2 terms for how layers travel over the network?
Encapsulation / Decapsulation
How does Encapsulation work?
What Layer does Encapsulation begin at?
Layers get ADDED as the data is prepared and sent to other senders.
Layer 7
How does Decapsulation work?
What Layer does Decapsulation begin at?
Layers get REMOVED as the data is received and processed by receivers
Layer 1 (Physical Layer)
What is the DOD Model?
How many Layers?
Department of Defence Model
4 Layers
What are the Layers of the DOD Model?
Network Access Layer (AKA Process)
Internet Layer
Transport Layer (AKA Host-to-Host)
Application Layer
What OSI layers are combined in the DOD Model Network Access Layer?
Physical and Data Link Layers
