Computer Networks

Introduction

• Computer Network is a group of two or more computers linked together.
• Connected by various mediums like cables, wireless adapters etc.
• Share common resources.

A collection of distributed, intelligent machines that shares data and information through interconnected lines of communication is called networking. When two or more computers are brought together in connection with cable or without cable, which may extend with in a limited room or to the entirely world, the computers are said to be network connection.

Devices required for computer Networking:

• Computers
• NIC (Network cards)
• Communication Media
• Network connecting devices
• Signal Conversion devices
• Communication Software

The Importance/Advantage of Computer Networks

• Sharing of devices such as printer and scanner.
• Sharing of Program/software.
• Sharing of Files.
• Sharing of Data.
• Sharing of Information.
• Sharing of Single high- speed internet connection.
• Can access server centered database.
• Better communication using internet services such as email, mailing list and Internet Related Chat (IRC).

Types of Computer Networks

Local Area Network
A local area network is usually privately owned and links the devices in a single office, building or campus of up to a few kilometers in size. Depending on the needs of an organization and the type of technology used, a LAN can be as simple as two PCs and printer in someone’s whole office, or it can extend throughout a company and include voice, sound, and video peripherals.

Metropolitan Area Network
A metropolitan area network is designed to extend over an entire city. It may be a single network such as a cable television network, or it may be a means of connecting a number of LAN’s into a larger network so that resources may be shared LAN to LAN as well as device to device.

Wide Area Network
The term Wide Area Network (WAN) is used to describe a computer network spanning a regional, national or global area. For example, for a large company the head quarters might be at Kathmandu and regional branches at Pokhara , Biratnagar , Dharan , Butwal etc.

Protocol
The standard rules and regulation of the networking system is called the protocol . The most common communication protocols are:

• TCP/IP (Transmission Control Protocol / Internet Protocol)
• PPP (Point to Point Protocol)
• HTTP (Hyper Text Transfer Protocol)
• FTP (File Transfer Protocol)
• SMTP (Simple Mail Transfer Protocol)
• POP (Post Office Protocol)
• WAP (Wireless Application Protocol)

TCP/IP
Most common communication protocol used to establish communication between different host, node, segment and operating system. It uses an IP address to identify the computer/system/node on the network system. IP Address: Numeric value like as: 192.168.0.21.

Some Web Terms

• Web Browser
• URL
• HTML (Hyper Text Markup Language)
• Domain
• ISP (Internet Service Provider)
• Search Engine
• Social Media

Top Level Domain
Extension : Meaning
.com : A company or business
.org : A non-profit institution
.gov : Governmental Agency
.mil : Military
.edu : Educational institution
.net : ISP or Network Provider