Unit IV — Internet: Terminologies & Technologies
The Internet is the world's largest Wide Area Network (WAN) — a global network of interconnected computers and servers communicating using standardised protocols. Understanding internet terminology and core technologies is essential for every computing student.
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Key Internet Terminologies
| Term | Definition |
|---|---|
| Internet | Global network of networks using TCP/IP protocols |
| Intranet | A private network (like the internet) within an organisation |
| Extranet | An intranet extended to authorised external users (partners, clients) |
| Protocol | Set of rules governing communication (e.g., TCP/IP, HTTP, FTP) |
| IP Address | Unique numerical identifier for each device on a network (e.g., 192.168.1.1) |
| Domain Name | Human-readable address mapped to an IP address (e.g., www.google.com) |
| DNS | Domain Name System — translates domain names to IP addresses |
| URL | Uniform Resource Locator — complete address of a web resource (e.g., https://www.google.com/search) |
| WWW | World Wide Web — a system of interlinked hypertext documents accessed via browsers |
| HTTP/HTTPS | HyperText Transfer Protocol (Secure) — protocol for web communication |
| FTP | File Transfer Protocol — for uploading/downloading files |
| SMTP/POP3/IMAP | Email protocols for sending and receiving mail |
| Browser | Software to access the WWW (Chrome, Firefox, Edge) |
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Internet Connection Types
| Type | Technology | Speed | Description |
|---|---|---|---|
| Dial-Up | Telephone line + modem | Up to 56 Kbps | Obsolete; very slow |
| DSL | Digital Subscriber Line | 1–100 Mbps | Uses existing telephone lines |
| Cable Internet | Coaxial cable TV network | 10–500 Mbps | Shared bandwidth |
| Fiber Optic | Fiber optic cable | 100 Mbps–10 Gbps | Fastest wired connection |
| Wi-Fi | IEEE 802.11 wireless | 54 Mbps–9.6 Gbps | Wireless LAN |
| Mobile (4G/5G) | Cellular radio | 10 Mbps–1 Gbps | Wireless WAN |
| Satellite | Geostationary satellites | 10–100 Mbps | Remote areas; high latency |
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Client-Server Model
In the client-server model, network functionality is split:
- Client — Requests services (your browser requesting a webpage).
- Server — Provides services (web server sending back the page).
This is the dominant model for the WWW, email, and databases.
Alternative: Peer-to-Peer (P2P) — Each node can be both client and server (BitTorrent, blockchain).
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Search Engines
A search engine is a web service that indexes and searches the web. Examples: Google, Bing, DuckDuckGo.
- Uses crawlers (spiders) to index web pages.
- Returns results ranked by relevance algorithms (PageRank).
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VoIP — Voice over Internet Protocol
- Transmits voice calls over the internet instead of traditional telephone networks.
- Examples: Skype, Zoom, WhatsApp calls, Teams.
- Converts voice to digital packets → transmitted via IP → reassembled at destination.
- Cost-effective for international calls.
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Networking Devices
| Device | Function |
|---|---|
| Repeater | Amplifies/regenerates signals to extend network range (Layer 1) |
| Hub | Broadcasts data to all devices (Layer 1); dumb device |
| Switch | Forwards data only to the intended device using MAC addresses (Layer 2); smart |
| Bridge | Connects two network segments; filters traffic using MAC addresses (Layer 2) |
| Router | Routes packets between different networks using IP addresses (Layer 3); connects LAN to WAN/internet |
| Gateway | Connects networks using different protocols; acts as a protocol translator |
| Firewall | Monitors and controls incoming/outgoing network traffic based on security rules |
| Modem | Modulates/demodulates signals to convert between digital and analog |
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Bluetooth Technology
- Short-range wireless technology (IEEE 802.15.1) operating at 2.4 GHz.
- Range: typically 10 metres (Class 2); up to 100 m (Class 1).
- Speed: Bluetooth 5.0 — up to 2 Mbps.
- Uses: Wireless headsets, keyboards, mice, file transfer, IoT devices.
- Forms a Personal Area Network (PAN).
Key Takeaway: The internet is built on TCP/IP protocols, DNS, and the client-server model. Key terminologies (URL, IP, DNS, HTTP, WWW) are frequently tested. For networking devices: remember the OSI layer for each — hub/repeater (L1), bridge/switch (L2), router (L3), gateway (L3+). Bluetooth = 2.4 GHz short-range PAN.