Networking - TCP/IP Model

What is the TCP/IP Model?

The TCP/IP model (Transmission Control Protocol/Internet Protocol) is a set of rules that allow computers to communicate over the internet.

Think of it like a postal system for the internet – it breaks down data into small packets, sends them across networks, and reassembles them at the destination.

TCP/IP Model Has 4 Layers (from bottom to top):

Layer No. Layer Name What It Does
1 Network Access (or Link) Moves data over physical network (cables, Wi-Fi)
2 Internet Layer Finds the best path to send data (using IP addresses)
3 Transport Layer Ensures data is sent reliably and in the correct order
4 Application Layer Interacts with software apps like web browsers or email apps

Quick Look at Each Layer

1. Network Access Layer

  • Deals with physical devices like routers, switches, and cables.

  • Responsible for sending data to nearby devices on the same network.

  • Works with technologies like Ethernet or Wi-Fi.

2. Internet Layer

  • Uses the IP (Internet Protocol) to give every device an address.

  • Chooses the best route for data to travel across networks.

3. Transport Layer

  • Uses TCP (for reliable delivery) or UDP (for faster delivery, like video streaming).

  • Ensures no data is lost or mixed up during transmission.

4. Application Layer

  • Where users interact with the network through apps like:

    • Web browsers (HTTP/HTTPS)

    • Email clients (SMTP, POP3)

    • File transfer tools (FTP)