๐ Notes
Communication & Computer Network
- Communication – Process of sharing ideas, information, feelings between sender and receiver.
- Computer Network – Collection of computers/devices connected to share data, hardware, software, and information.
- Need for Network – Resource sharing saves time and money.
- Data Sharing – Authorized users can access shared databases/files.
- Hardware Sharing – Devices like printers can be shared across network.
- Software Sharing – Programs stored centrally can be accessed by multiple users.
- Electronic Funds Transfer (EFT) – Transfer of money via credit/debit cards, online banking.
Network Components
- Sender – Device that initiates data transfer.
- Receiver – Device that receives data.
- Communication Channel – Medium (cables, microwave, satellites).
- Protocol – Rules for communication between devices.
- Server – Powerful computer managing files/resources.
- Workstation/Peer – Less powerful computers connected to server.
Types of Networks
- LAN (Local Area Network) – Small area (home, school, office).
- MAN (Metropolitan Area Network) – Connects LANs across a city/town.
- WAN (Wide Area Network) – Large area, country/world; Internet is the largest WAN.
- PAN (Personal Area Network) – Connects personal devices (phones, laptops) via Bluetooth/Wi-Fi.
Network Hardware
- Computer – Core device in a network.
- NIC (Network Interface Card) – Provides network access to devices.
- Hub – Central connection point for cables; broadcasts data to all.
- Switch – Forwards data to specific destination; more efficient than hub.
- Router – Connects multiple networks (e.g., LAN to Internet).
- Cables – Twisted pair, coaxial, fiber-optic.
- Resource – Any part of system (disk, printer, memory) usable by programs.
Communication Channels
- Physical Media – Twisted pair, coaxial, fiber-optic cables.
- Wireless Media – Infrared, broadcast radio, Wi-Fi, cellular radio, microwave, satellites.
Network Architecture
- Peer-to-Peer Network – All computers equal; best for small networks.
- Client/Server Network – Server provides resources; clients request services.
- File Server – Stores files.
- Print Server – Manages printers.
- Database Server – Stores databases.
- Network Server – Manages traffic.
- Web Server – Delivers web pages.
Network Topology
- Bus Topology – All devices connected to single cable; linear.
- Star Topology – Hub at center; easy to add/remove nodes.
- Ring Topology – Devices connected in circular chain; failure of one affects all.
Protocols
- HTTP – Transfers web pages.
- FTP – Upload/download files.
- TCP/IP – Standard for Internet communication.
- POP3 – Downloads emails from server (removed after download).
- IMAP – Access emails directly on server (available across devices).
- SMTP – Sends emails across Internet.
Digital Citizenship
- Definition – Responsible and ethical use of technology.
- Guidelines:
- Treat others with respect online.
- Avoid cyberbullying, hate speech, harassment.
- Protect personal information and privacy.
- Use strong passwords/security.
- Respect copyright and intellectual property.
