Understanding LAN, WAN, and Internet Networks
Network Information
LAN and WAN Networks
LAN (Local Area Network) and WAN (Wide Area Network) are networks that connect two or more computers, often within a local area. These networks facilitate the sharing of information, documents, and programs.
LAN: A local network.
WAN: Often refers to the internet.
To physically connect computers in a LAN, you need network cables and a network card with a connector. A braided cable, consisting of four pairs of wires, connects to a HUB, which acts as a distributor, creating a star network topology where all computers connect to a central point (the HUB). Older networks used direct computer-to-computer connections, which are now less common.
Transmission speed depends on the amount of information being transmitted. Fiber optic cables increase speed.
Network Functioning Types:
- Peer-to-Peer: Two computers have equal status.
- Client-Server: A main computer (server) provides services to other computers (clients).
- Ethernet: A network type that transmits data in packets, facilitating efficient information transfer. Faster Ethernet versions offer increased speed.
- Token-Ring Network: A closed network, often used by large companies.
- ATN (Asynchronous Transfer Mode): Used for secure information transfer, breaking data into fixed-size cells.
Intranets and the Internet are smaller networks protected by firewalls, which are security systems that prevent unauthorized network intrusion. Firewalls can be implemented in software or hardware.
The Telephone Network in Computing
The telephone network requires a physical cable to transmit information to computers. To switch between different networks, a physical connection is needed, either through a cable or the existing telephone network infrastructure. Due to potential problems and high demand, data often passes through a mesh of central nodes.
Each computer connects via a node (telephone line).
- Normal: Low capacity.
- ADSL: Phone lines that share voice and data simultaneously, providing a broadband connection.
- Analog: Can be used for either voice or data, but not both simultaneously.
- ISDN: A dual analog line with one line for internet and another for voice, but with limited speed.
Equipment
Analog lines use modems to connect computers to the network. ADSL uses routers. Download speeds are typically higher than upload speeds and are measured in kb/s or Mb/s.
Connection types include:
- Wired (fiber optic)
- Telephone connections
- Satellite (mobile) wireless connections (becoming cheaper and more improved)
Email is a primary form of communication. An email address consists of a username (left of the @ symbol) and a provider name (right of the @ symbol).
Web-server: Mailboxes with more capabilities (e.g., Hotmail, Yahoo).
POP3: A program (e.g., Outlook) that manages mail locally on the computer, requiring antivirus protection.
Internet
The Internet is a network of networks used to share information globally. It was initially created for the U.S. military and universities to facilitate research. Websites are evolving towards Web 2.0, becoming more dynamic and utilizing secure protocols. HTML is the basic programming language for websites, and social networks are now prevalent. The Internet is a mass communication medium, with television networks also utilizing it. Examples of Internet browsers include Mozilla Firefox and Internet Explorer.