NETWORKING FUNDAMENTALS
A network can be defined as an interconnected collection of autonomous computers. A ‘computer network’ or simply a ‘network’ is a collection of computers and other hardware devices, interconnected by communication channels (satellites or cables) that allow sharing of resources and information. Computer networking is the practice for exchanging information/services between two or more computer devices together for the purpose of sharing data.
The speed of a network is measured in Mbps (Megabits per second).
Networks are designed using the following architecture:
1) Peer-to-Peer (P2P) Architecture: Networks in which all computers have an equal status are called peer to peer networks. Generally in such a network each terminal has an equally competent CPU.
2) Client-Server Architecture: Networks in which certain computers have special dedicated tasks, providing services to other computers (in the network) are called client server networks.
The computer(s) which provide services are called servers and the ones that use these services are called clients.
BENEFITS OF NETWORKING
Computer network is very useful in the modern environment, so some of the benefits of networking are discussed here:
- Data Sharing: One of the most important uses of networking is to allow the sharing of data.
- File-Sharing: The networking of computers helps the users to share data files.
- Hardware Sharing: Users can share devices such as printers, scanners, CD-ROM drives, hard drives, etc.
- Application Sharing: Applications can be shared over the network and this allows to implement client/server applications.
- User Communication: This allows users to communicate using E-mail, newsgroups, and video conferencing within the network.
- Access to Remote Database: By networking, we are able to access the remote database. It is easy for any person using his PC to make reservations for airplanes, trains, hotels, etc., anywhere in the world with instant confirmation within the network.
TYPES OF NETWORK
A network refers to a group of interconnected computers which are capable of sharing information and communication devices.
On the basis of coverage or geographical spread, a network can be divided into following types:
LAN (Local Area Network)
When a group of computers and their devices are connected in a small area, then this network is said to be a LAN. Computers or users in a local area network can share data, information, software, and common hardware devices such as printers, modems, hard disks, etc. A LAN typically relies mostly on wired connections for increased speed and security but wireless connections also be a part of LAN. LANs are used within an office building, schools, etc.
MAN (Metropolitan Area Network)
This is basically bigger version of LAN and normally uses similar technology. It might cover few buildings in a city and might either be private or public. e.g. In a city, a MAN, which can support both data and voice might even be related to local cable television network.
WAN (Wide Area Network)
The network which connects the different countries network is known as WAN. It can be a group of LANs. The largest existing WAN is Internet. For example, a network of ATMs, BANKs, National Government Offices spread over a country or continents are examples of WANs.
INTERNET:
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide. It is a network of networks.
Uses of the Internet: There are various uses of Internet. Some of them are listed below
- Internet is used by students, and educational institutes to gather information for research.
- It is used for online shopping.
- It is used for sending and receiving mail.
- It is used for playing games.
- It is used for Online Transactions.
World Wide Web: World Wide Web (abbreviated as WWW or W3, commonly known as the Web), is a system of interlinked hypertext documents accessed via the Internet.
Web Browser: A Web Browser is a software used to view Web sites and acts as an interface between the user and the World Wide Web.
Web Server: Web server is a computer that stores web sites and their related files for viewing on the Internet.
Internet Service Provider: An Internet service provider (ISP) is an organization which provides you with access to the Internet via a dial-up (using modem) or direct (hard wired) or wireless connection. for example Bharat Sanchar Nigam Limited (BSNL), Airtel, MTS, Vodafone, Tata Docomo, etc.
Modem: It stands for MOdulator/DEModulator. It is a device that converts digital computer signals into a form analog signal and vice versa.
Types of Common Internet Connectivity: There are different types of Internet Connectivity available today; it can be widely categorized into wired and wireless access.
| Technology | Type of Connectivity |
| Dial-up | Wired |
| DSL | Wired |
| Cable Internet Access | Wired |
| 3G | Wireless |
| WiMAX | Wireless |
| Wi-Fi | Wireless |
Some of the commonly used Internet connectivity are:
1) Dial-up connections are extremely slow and in most cases, it is replaced by a high speed connection such as DSL or Cable Modem.
2) DSL: Digital subscriber line(DSL) provide Internet access by transmitting digital data over wires of a local telephone network. DSL service is delivered along with wired telephone service on the same telephone line. On the customer premises, a DSL filter removes the high frequency interference, enabling simultaneous use of the telephone and data transmission. For using a DSL connection, you need a DSL modem and a subscription.
3) Cable Internet Access: Cable Internet Access is a form of broadband Internet access that uses the cable television infrastructure. Cable Internet Access is provided through existing cable TV networks; this is similar to DSL which is provided over existing telephone lines.
4) 3G: 3G, short for 3rd Generation is a set of standards used for mobile devices and mobile telecommunication services and networks. High-Speed Downlink Packet Access (HSDPA) is 3G a mobile telephony communications protocol that allows higher data transfer speeds and capacity.
5) WiMAX: WiMAX (Worldwide Interoperability for Microwave Access) is a wireless communications standard designed to provide mobile broadband connectivity across cities and countries through a variety of devices. WiMAX is a long range system, covering many kilometres and is typically used where DSL or Cable Internet Access cannot be used; this could be difficulty in laying out cables for home or offices located in remote locations but need access to the Internet.
6) WI-Fi : Wi-Fi (Wireless Fidelity) is a popular technology that allows an electronic device such as computers or mobile phones to exchange data wirelessly over a network, including high-speed Internet connections. WiFi devices such as personal computer, smartphones, video game console, etc. can connect to a network resource such as Internet through a device called the Wireless Access Point (WAP).
Wi-Fi is used where cables cannot be run (such as old buildings, outdoor areas) to provide network and Internet access. Wi-Fi can also be used where users require mobile connectivity.
Wi-Fi connectivity is used in home & offices, hotels, college & school campus typically for Internet Access. Shopping malls, coffee shops, resorts mostly offer free or paid Wi-Fi access to the Internet for their customers.
INSTANT MESSAGING
Instant messaging (IM) is a form of communication over the Internet that offers an instantaneous transmission of text-based messages from sender to receiver.
Types of Instant Messaging Software:
There are two kinds of instant messaging software – application based and Web based.
A) Application based: Application based instant messaging software is downloaded and installed on user’s computer.
Some of the popular instant messaging software are:
Google Talk
Yahoo! Messenger
Skype
Windows Live Messenger
Rediff Bol, etc.
B) Web based: Web based instant messaging software is accessed using browsers such as Internet Explorer, Mozilla Firefox, Google Chrome, etc. Some of the popular web based instant messaging software are:
- Meebo
- Yahoo! Messenger for the Web
- MSN Web Messenger
- IMO, etc.
Key Features of an instant messaging are as follows:
- Text Messages can be sent to one or more person (Similar to SMS)
- Audio calling and conferencing.
- Video calling and conferencing.
- File transfers (Not limited to documents, spread sheets, audio files, video files, etc.)
- Message history (Save messages for future reference).
NOTE: To use instant messaging software, a user must have a valid instant messaging account.
