Hey everyone, today I’ll describe Computer Networking Systems. Diving deeper into computer networking systems involves understanding how data is transmitted across various types of networks, the architecture of networking models, and the various protocols that govern communication. Let's explore key concepts, types of networks, layered architectures, and how they function in detail.
What is a Computer Network?
A computer network is a group of computers and other devices (like phones, routers) connected to each other, allowing them to communicate and share data. The Internet is the largest example of a network.
Types of Networks
1. LAN (Local Area Network):
A LAN connects devices within a small geographical area (like a home, office, or building).
Example: Devices connect via Ethernet cables or Wi-Fi to a home router.
2. WAN (Wide Area Network):
WAN connects devices across broader geographical areas (cities, countries, etc.).
The Internet is the largest WAN.
3. MAN (Metropolitan Area Network):
MAN covers a larger area than a LAN but smaller than a WAN, typically a city.
Example: Networks that connect branches of banks across a city.
4. PAN (Personal Area Network):
A PAN is used to connect devices around a single person.
Example: Bluetooth connections between your phone and wireless earbuds.
5. VPN (Virtual Private Networking):
A VPN extends a private network across a public network, allowing users to send and receive data as if their devices were connected directly to the private network.
Example: Remote workers using a VPN to securely access company resources.
What are Protocols?
Protocols are rules that govern how data is transmitted over a network. They ensure that devices can communicate with each other effectively.
Common Protocols:
HTTP (HyperText Transfer Protocol):
It is the protocol used for browsing the web.
It defines how data (web pages, images, etc.) is transmitted between a browser and a web server.
Example: When you type
http://google.com, your browser sends a request to the server, and the server responds by sending the requested web page.
HTTPS (HTTP Secure):
It is an encrypted version of HTTP.
It ensures secure communication between your browser and the server using SSL/TLS encryption.
Example: When you visit
https://google.com, your connection is secured so that attackers cannot easily intercept sensitive data like passwords.
SSH (Secure Shell):
It is a protocol for securely accessing and managing remote servers over a network.
It uses encryption to keep the connection secure.
Developers and system administrators often use SSH to connect to servers and execute commands remotely.
Example: When you SSH into a server, you can control that server from your local machine as if you were directly connected to it.
Ports in Networking
Think of ports as "virtual doors" on a device or server. Each port allows communication using a specific protocol. When data arrives at a port, the operating system directs the data to the appropriate service (like a web browser or email app).
How Ports Work:
Port Numbers:
Ports are identified by numbers, ranging from 0 to 65535.
Some common ports:
Port 80: Used by HTTP
Port 443: Used by HTTPS
Port 22: Used by SSH
Port 25: Used by SMTP (for email)
When you access a website, your browser connects to a web server on port 80 (for HTTP) or port 443 (for HTTPS). The server listens on these ports for incoming requests.
How Ports are Opened:
Servers or computers can have multiple ports open to handle different types of connections (e.g., one port for web traffic, another for email).
A firewall can be used to control which ports are open to outside connections, providing a layer of security.
How Data Flows in a Network:
When you visit a website, here's a simplified flow of what happens:
DNS (Domain Name System): Your browser first converts the domain name (e.g.,
google.com) to an IP address, which identifies the server.Request: Your browser sends an HTTP/HTTPS request to the server's IP address on port 80 (HTTP) or port 443 (HTTPS).
Response: The server processes the request and sends the requested data (e.g., a web page) back to your browser.
Data Transfer: The data is transmitted over the network, broken into small chunks called "packets." These packets are reassembled when they reach your computer.
IP Addresses
An IP address is a unique identifier for a device on a network. It's similar to a home address but for devices.
Types of IP addresses:
IPv4 (e.g., 192.168.1.1): A 32-bit address.
IPv6 (e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334): A 128-bit address, created to accommodate the growing number of devices on the internet.
Conclusion
Computer networks form the backbone of modern communication and data exchange, enabling devices, systems, and users to connect, share information, and collaborate globally. At its core, a network allows data to flow between computers using standardized rules known as protocols (such as HTTP, HTTPS, and SSH) and infrastructure elements like ports and IP addresses.