1. What is the Internet, and How Does It Work?
We’ve been using the internet for years, but have you ever paused to wonder how it actually works? 🤔 Let’s demystify it!
The internet connects billions of devices worldwide using a tiered system:
Tier 1: These are the backbone providers, owning massive networks of fiber-optic cables (including those under oceans 🌊!) to connect continents. They invest billions to keep the world connected.
Tier 2: These companies rent bandwidth from Tier 1 providers and act as regional distributors. For example, think of your national internet providers like BT or Comcast.
Tier 3: These are the local ISPs (Internet Service Providers) that provide internet to individuals and businesses through mobile data plans or home Wi-Fi services.
Analogy: Imagine a global postal system. Tier 1 is like the international cargo carriers transporting goods across countries 🌍. Tier 2 handles regional distribution, like DHL or FedEx, and Tier 3 is your local post office delivering packages to your doorstep 📦.
2. OSI and TCP/IP Models
When we talk about how the internet works, we often refer to two models: OSI (Open Systems Interconnection) and TCP/IP (Transmission Control Protocol/Internet Protocol).
OSI Model - The Theoretical Approach
The OSI model is like the blueprint for how data is transferred over a network. It has seven layers, each with a specific role:
(image source:- neosnetworks.com/resources/blog/what-is-osi..)
Application Layer: This is what the user interacts with (e.g., your browser).
Presentation Layer: Translates data into readable formats (like encoding or encryption).
Session Layer: Manages sessions between devices (like starting/stopping a connection).
Transport Layer: Ensures data delivery (using TCP/UDP).
Network Layer: Assigns unique addresses (IP) to identify devices.
Data Link Layer: Manages direct connections between devices in the same network.
Physical Layer: Handles actual hardware (like cables and switches).
Analogy: Imagine a couple in different countries communicating via mail.
Application Layer: The boyfriend writes a letter (data).
Presentation Layer: The letter is written in a language they both understand.
Session Layer: The girlfriend opens the mailbox (session starts) and closes it after reading the letter (session ends).
Transport Layer: Ensures the letter is delivered without getting lost.
Network Layer: The envelope has their unique addresses (IP).
Data Link Layer: The postman ensures the letter gets to the right local address.
Physical Layer: The roads and vehicles used to transport the letter.
TCP/IP Model - The Practical Approach
In the real world, the internet uses the TCP/IP model, which simplifies the OSI model into four layers:
(image source:- techtarget.com/searchnetworking/definition/..)
Application Layer: Combines the Application, Presentation, and Session layers of OSI. Protocols like HTTP, FTP, and SSH operate here.
- Example: When you browse a website, HTTP ensures the page loads correctly.
Transport Layer: Uses TCP or UDP.
TCP: Like downloading a YouTube video – data is buffered, ensuring no packet loss.
- Example: (Like watching a “how to become a Kubernetes expert in one day” tutorial on YouTube – not happening but enjoy the “magic” 😉).
UDP: Like live streaming – data is sent in real-time but might face lag if there’s poor connectivity.
- Example: (You know that epic gaming stream you’re watching, but your favorite gamer starts lagging because their Wi-Fi decided to have a meltdown? Yeah, that’s UDP for you 🤷).
Internet Layer: Assigns unique IP addresses to devices for routing data.
- Example: Like giving your home address to Amazon so your parcel can find you.
Network Interface Layer: Deals with physical connections and ports.
- Example: Your home router is like a port that connects ships (data packets) to the internet. 🌐
3. What Are IP and MAC Addresses?
MAC Address (Media Access Control): A physical address assigned to your device by its manufacturer.
Example: Think of a school computer lab where all PCs are connected in a network. When your device faces issues, the IT guy asks for your MAC address to identify the exact machine.
Note: MAC addresses don’t change when you restart your system.
IP Address (Internet Protocol): A dynamic address assigned to your device when connected to a network. It changes depending on the network you’re using.
- Example: If you switch from home Wi-Fi to a café’s Wi-Fi, your device gets a new IP address.
4. What Are Routers, Firewalls, and Switches?
Router: A device that brings the internet to your house.
- Example: When you buy Wi-Fi, the ISP installs a router to connect your home to the internet.
Firewall: Think of it as a security guard that blocks unauthorized access to your network.
- Example: Like bouncers at a club ensuring only cool, authorized guests can enter.
Switch: A device used to connect multiple devices in the same local network.
- Example: In school computer labs, the rectangular box with many cables plugged into it is a switch, ensuring all computers can share the same network.
5. Case Study: How a Company Uses Networking Tools
Let’s take Netflix as an example:
IP Address: Netflix assigns an IP address to identify your location and provide localized content (say, the content you can’t access because of licensing restrictions 🙄).
Routers and Switches: Netflix uses data centers worldwide with routers and switches ensuring smooth data flow.
Firewalls: Netflix’s firewalls protect their servers from unauthorized access, ensuring your account stays secure.
TCP: When you download a movie, TCP ensures that the content is buffered without losing quality.
UDP: When you live stream, UDP is used to deliver real-time data, but there’s a chance for lag if the connection is poor.
This is just the beginning of our 90 Days of DevOps challenge. In the next posts, we’ll dive deeper into core DevOps tools and concepts!
What do you think of these networking basics? Let me know in the comments!