The latest articles on DEV Community by SKANDA B H (@skanda_bh_cb430cb3e6d904). https://dev.to/skanda_bh_cb430cb3e6d904 https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F3971103%2Fa16e960f-f046-433b-8b7d-f0e33b0e16b7.png https://dev.to/skanda_bh_cb430cb3e6d904 en SKANDA B H Sat, 06 Jun 2026 11:50:37 +0000 https://dev.to/skanda_bh_cb430cb3e6d904/day-1-ccna-learning-3o6e https://dev.to/skanda_bh_cb430cb3e6d904/day-1-ccna-learning-3o6e <h1> Map Computer Networking with Real-World </h1> <h2> What is Computer Networking? </h2> <p>Computer networking is the process of connecting devices so they can communicate and share resources.</p> <p>Think of networking like a city's road system.</p> <ul> <li>Devices = Houses and offices</li> <li>Data packets = Vehicles</li> <li>Cables and Wi-Fi = Roads</li> <li>Switches and routers = Traffic controllers</li> <li>Internet = Global highway network</li> </ul> <p>Imagine you are sitting at home and open YouTube.</p> <p>Your request travels through:</p> <p>Laptop → Home Wi-Fi Router → ISP Network → Internet → YouTube Server</p> <p>The server then sends video packets back to your device.</p> <p>This entire process usually happens within milliseconds.</p> <h2> Networking Devices </h2> <h3> Client </h3> <p>A client is a device that requests resources.</p> <p>eg:</p> <ul> <li>Your mobile phone opening Instagram</li> <li>Your laptop accessing Google</li> <li>Your smart TV streaming Netflix</li> </ul> <p>The client always initiates the request.</p> <h3> Server </h3> <p>A server provides resources or services.</p> <p>Eg:</p> <ul> <li>YouTube servers store videos</li> <li>Gmail servers store emails</li> <li>Amazon servers host shopping applications</li> </ul> <p>Without servers, websites and apps would not exist.</p> <h3> Switch </h3> <p>A switch connects devices inside a Local Area Network.</p> <p>Real-world example:</p> <p>Suppose a company has:</p> <ul> <li>50 employees</li> <li>50 computers</li> <li>10 printers</li> </ul> <p>All these devices connect to a switch.</p> <p>The switch learns which device is connected to which port and sends data only to the intended destination.</p> <p>Think of it as a smart receptionist who knows exactly where every employee sits.</p> <h3> Hub </h3> <p>A hub is an old networking device.</p> <p>Eg:<br> If Employee A wants to send a file to Employee B:</p> <p>The hub sends that data to ALL connected devices.</p> <p>Everyone receives it even though only Employee B needs it.</p> <p>Think of a teacher shouting one student's message to the entire classroom.</p> <p>This creates unnecessary traffic.</p> <p>That's why switches replaced hubs.</p> <h3> Router </h3> <p>A router connects different networks together.</p> <p>Eg:</p> <p>Your home Wi-Fi and Google's network are different networks.</p> <p>The router helps packets travel between them.</p> <p>Think of a router as a GPS navigator that decides which path vehicles should take.</p> <p>Without routers, the Internet cannot function.</p> <h3> Firewall </h3> <p>A firewall protects the network. It is a Security device</p> <p>Eg:<br> A company may allow:</p> <ul> <li>Employees to access websites</li> <li>Email traffic</li> <li>VPN traffic</li> </ul> <p>But block:</p> <ul> <li>Hackers</li> <li>Malware</li> <li>Unauthorized access</li> </ul> <p>Think of a firewall as a security guard at a company gate.<br> Windows/Microsoft defender firewall you may have seen which is software firewall , where big organizations gave hardware or cloud firewalls<br> An NGFW is a smarter firewall.<br> Besides basic filtering, it can:<br> Think of it as an AI-powered security team instead of a single security guard.</p> <h2> Network Types </h2> <h3> PAN (Personal Area Network) </h3> <p>A small network around one person.</p> <p>Examples:</p> <ul> <li>Bluetooth headset</li> <li>Smartwatch</li> <li>Wireless keyboard</li> </ul> <p>Coverage: Few meters</p> <h3> LAN (Local Area Network) </h3> <p>A network inside a building.</p> <p>Examples:</p> <ul> <li>Home Wi-Fi</li> <li>College lab</li> <li>Office network</li> </ul> <p>Coverage: Building or campus</p> <h3> MAN (Metropolitan Area Network) </h3> <p>A network covering an entire city.<br> Examples:</p> <ul> <li>City-wide surveillance systems</li> <li>Public Wi-Fi infrastructure</li> </ul> <p>Coverage: City</p> <h3> WAN (Wide Area Network) </h3> <p>A network connecting multiple cities, states, or countries.<br> Examples:</p> <ul> <li>Bank branch connectivity</li> <li>Corporate global offices</li> <li>The Internet</li> </ul> <p>Coverage: Worldwide</p> <h2> What Does an ISP Actually Sell? </h2> <p>Most people think they are paying for data.</p> <p>In reality, they are paying for access to networking infrastructure.</p> <p>Examples:</p> <ul> <li>Fiber cables</li> <li>Routers</li> <li>Towers</li> <li>International links</li> <li>Data centers</li> </ul> <p>ISPs such as Jio, Airtel, BSNL, and Vi transport packets from your device to the destination and back.</p> <h2> Key Takeaways </h2> <ul> <li>Clients request services.</li> <li>Servers provide services.</li> <li>Switches connect devices within a network.</li> <li>Routers connect different networks.</li> <li>Firewalls protect networks.</li> <li>Packets carry information.</li> <li>ISPs transport packets across the Internet.</li> <li>Networking is the foundation of every modern application.</li> </ul> beginners learning networking tutorial