Computer Network Basics in English

 

Fundamental Concepts:

• Definition: A computer network is a collection of interconnected devices (computers, servers, routers, etc.) that can communicate and share resources.
• Purpose: Resource sharing (files, printers, internet), communication (email, instant messaging), and data exchange.
• Nodes: Devices connected to the network.
• Links: The communication pathways between nodes (wired or wireless).
• Data Transmission: Data is broken into packets for efficient transmission.

Types of Networks:

• LAN (Local Area Network): Covers a small geographical area (home, office).
• WAN (Wide Area Network): Covers a large geographical area (cities, countries).
• MAN (Metropolitan Area Network): Covers a metropolitan area (city).
• PAN (Personal Area Network): Covers a very small area, typically for personal devices.
• WLAN (Wireless Local Area Network): A LAN that uses wireless connections.
• VPN (Virtual Private Network): Extends a private network across a public network.

Network Topologies:

• Bus Topology: All devices connected to a single cable (linear).
• Star Topology: All devices connected to a central hub or switch.
• Ring Topology: Devices connected in a closed loop.
• Mesh Topology: Every device connected to every other device (highly redundant).
• Tree Topology: A combination of star and bus topologies.

Network Devices:

• Router: Forwards data packets between networks.
• Switch: Connects devices within a LAN and forwards data packets.
• Hub: Connects devices within a LAN (less efficient than a switch).
• Modem: Converts digital signals to analog and vice versa.
• Firewall: Security device that filters network traffic.
• Access Point: Enables wireless devices to connect to a wired network.

Network Protocols:

• TCP/IP (Transmission Control Protocol/Internet Protocol): The foundation of the internet.
• HTTP/HTTPS (Hypertext Transfer Protocol/Secure): For web browsing.
• DNS (Domain Name System): Translates domain names to IP addresses.
• IP (Internet Protocol): Addresses and routes packets.
• TCP (Transmission Control Protocol): Ensures reliable data delivery.
• UDP (User Datagram Protocol): Faster but less reliable data delivery.
• FTP (File Transfer Protocol): For transferring files.
• SMTP (Simple Mail Transfer Protocol): For sending email.

IP Addressing:

• IP Address: A unique identifier for a device on a network.
• IPv4: 32-bit addresses (e.g., 192.168.1.1).
• IPv6: 128-bit addresses (more addresses, e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334).
• Subnet Mask: Defines the network portion of an IP address.
• Default Gateway: The IP address of the router that connects the local network to other networks.

OSI Model (Open Systems Interconnection):

• A conceptual framework that standardizes the functions of a telecommunication or computing system, without regard to its underlying internal structure ¹ and technology. It characterizes computing functions into a universal set of rules and requirements.  (Ref: 1. brainly.com)
• 7 Layers:
  • Physical (hardware)
  • Data Link (MAC addressing)
  • Network (IP addressing, routing)
  • Transport (TCP, UDP)
  • Session (managing connections)
  • Presentation (data formatting)
  • Application (user interface).

Security Basics:

• Firewalls: Prevent unauthorized access.
• Encryption: Protects data confidentiality.
• Antivirus/Antimalware: Protects against malicious software.
• Passwords: Secure access to devices and accounts.
• VPNs: Create secure connections over public networks.
• Network segmentation: Isolating parts of the network to limit the damage done by a security breach.