Common Terminologies¶
The Internet¶
The global network connecting devices.
The WWW¶
A service running on the internet that provides web content.
| Feature | World Wide Web (WWW) | Internet |
|---|---|---|
| Definition | A system of interlinked web pages and resources accessed via browsers. | A global network of interconnected computers and servers. |
| Purpose | Enables users to access and share web pages, images, videos, and other content. | Provides the infrastructure for communication, data transfer, and networking. |
| Components | Web pages, hyperlinks, browsers, HTTP, HTML, URLs. | Routers, switches, servers, ISPs, protocols (TCP/IP). |
| Protocols Used | Uses HTTP/HTTPS for web browsing. | Uses multiple protocols (TCP/IP, FTP, SMTP, DNS, etc.). |
| Dependency | Depends on the internet to function. | Can exist without the web (e.g., email, file sharing). |
| Example | Browsing Facebook, YouTube, or Wikipedia. | Sending an email, using WhatsApp, online gaming, video calls. |
Connection-Oriented Service (Virtual Circuit)¶
Definition: A communication service where a connection is established between sender and receiver before any data is transferred, much like a telephone call.
Protocol Example: TCP (Transmission Control Protocol)
Key Features:
- A virtual circuit is established (logical path).
- Data arrives in order.
- Reliable: guarantees delivery, error checking, and flow control.
- Connection must be set up and closed explicitly.
Analogy: Like a phone call—you dial, connect, talk, and then hang up.
Connectionless Service (Datagram)¶
Definition: A communication service where each message (datagram) is sent independently without establishing a connection.
Protocol Example: UDP (User Datagram Protocol)
Key Features:
- No setup phase (no connection).
- Each packet (datagram) is routed independently.
- Unreliable: packets may arrive out of order, be duplicated, or lost.
- Lower overhead and faster for simple tasks.
Analogy: Like sending postcards—each one is sent individually and may arrive out of order or not at all.
Note : Both VC and Datagram are similar to TCP/UDP but not same VC and Datagram work at Network layer.