Learning Objectives
1
The TCP/IP 4-Layer Model
Click a layer to explore:
SOFTWARE
Application Layer
This is where network applications like Web Browsers (Chrome) and Email (Outlook) operate.
Key Protocols
HTTP, HTTPS, FTP, SMTP, POP, IMAP
2
Benefits of Layers
Decomposition
It breaks a complex problem (networking) into smaller, manageable pieces. Each layer has a single job.
Interoperability
Devices from different manufacturers (e.g., Apple & Samsung) work together because they follow the same layer rules.
Self-Contained Updates
You can change one layer without breaking others. E.g., Upgrading to 5G changes the Link Layer, but your apps still work.
3
How Layers Work: Encapsulation
When data moves DOWN the layers, it is wrapped in an "envelope" of extra information. This is called Encapsulation.
App Layer
DATA (The photo/email)
Transport Layer
TCP Header
DATA
Internet Layer
IP Address
TCP
DATA
Think of it like a Russian Doll: The Application data is put inside a Transport packet, which is put inside an Internet packet. At the other end, the computer unwraps them one by one!
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