Networking for DevOps

How does the Internet work:

• 🌐 What is the Internet?
  The Internet is a global network 🌍 that allows computers 💻 to communicate with one another 🔄 and transfer data 📡 between different systems around the world 🌎.

• 🌐 How it works?
  Tier 1 companies (like AT&T, NTT, etc.) 🏢 lay fiber-optic cables under the sea 🌊 to establish the global internet infrastructure 🌍.

  Tier 2 companies 🛰️ then lease bandwidth from these Tier 1 providers.

  Subsequently, Tier 3 companies (such as VI, BSNL, etc.) 📡 purchase bandwidth from Tier 2 providers and sell it to end users 👥.

  We buy data packs 📶 from Tier 3 companies and use them on our devices 📱💻 (such as mobile phones and laptops).

OSI Model & TCP/IP Model:

• 🔌 OSI Model:

  The Open Systems Interconnection (OSI) model has 7 layers 🧱. These layers describe the entire process of communication between two devices 📱💻 and explain how data passes through each stage from sender to receiver. 📤➡️📥

• 🌐 TCP/IP Model:
  The Transmission Control Protocol/Internet Protocol (TCP/IP) has 4 layers. 🧱 These layers are actually used in real-life networking. 🌍 This model shows how data is transferred 📤📥 between two devices, like computers or smartphones. 💻📱

IP & MAC Address:

• 🌐 IP Address:

  The Internet Protocol (IP) is used to identify devices on the Internet. 🌐 There are two versions of IP: IPv4 and IPv6. 🔢📡 (Identify device as a Wide Area Network)
  ➡️ IPv4 uses a 32-bit address format.
  ➡️ IPv6 uses a 128-bit address format.

• MAC Address 🔍
  The Media Access Control (MAC) address is a unique identifier assigned to devices on a Local Area Network (LAN) 🌐. It helps differentiate one device from another for communication within the network 🖧.

Routers & Switches:

• 🛜 Routers:
  A router is a networking device that acts as a gateway 🌐, connecting multiple networks and enables data transfer between them 🔄.

• 🔌 Switches:
  Switches connect multiple network devices, which allows them to communicate 💬 and share resources 📁 efficiently.

Firewall, Ports, Protocols:

• 🔥 Firewall:
  A firewall is a network security device that monitors 🔍 and controls 🛑 incoming and outgoing traffic based on predefined rules 📜 to protect your system from threats. 🛡️💻

• 🔌 Ports:
  Ports are numerical channels that enable communication between applications and services. 🖥️

• Protocols 🧾:
  Protocols define the rules for how data is transmitted 📡 over a network 🌐.

Client-Server Architecture:

• 💻 Client-server architecture is a network model where multiple clients request and receive services from a centralized server. 🌐🖥️