Welcome to our very first tutorial about computer networks. In this tutorial we will briefly define computer network. Why we need computer network? Brief history of computers and basic types of network. So are you ready to jump into computer networks? Let’s jump in
A computer network is a group of connected communicating devices such as computers and printers. A network is series of points or nodes interconnected by communication links. Networks can be interconnected with other networks and may contain sub networks.
Why Computer Networks?
Before the advent of computer networks business activities were carried out manually i-e paper work. Much amount of information caused information searching and analysis more difficult. Information exchange took hours even days to get there causing delays in critical decisions.
Necessity is the mother of invention.
Text, audio and video data need to be communicated/exchange at remote location. Communication needs to be;
Let’s go 55 years back in 1960s
Mainframe computers in research organization were standalone devices (no networks).
Advance Research Projects Agency (ARPA) in Department of Defense (DoD) had funded some researcher and the researchers needed to share their finding with each other. ARPA decided to have such an infrastructure that could provide facility to exchange information by reducing costs.
ARPA had meeting with Association for Computing Machinery (ACM) and presented the idea for ARPANET.
ARPANET – A small network of connected computers.
Each host computer would be attached to a specialized computer called Interface Message Processor (IMP). Each IMP had to be able to communicate with each other IMPs as well as with its own attached host.
ARPANET first implement four nodes The University of California at Los Angeles (UCLA), The University of California at Santa Barbara (UCSB), Stanford Research Institute (SRI) and University of Utah were connected via IMPs to form a network. A software called Network Control Protocol (NCP) provided communication between the hosts.
Diagram of 4 Nodes APRANET
Business decisions have to be made ever more quickly. Decision makers require immediate access to data/information. Data is supposed to be confidential hence require security.
Types of Network
Local Area Network (LAN)
- Usually privately owned
- Links the devices in a single office/building about few kilometers
- Designed to allow resource sharing like printer, application program or data
Distinguish from other types of network by;
- Transmission media
- Topologies (Most common are Bus, Ring and Star) [will discuss on next tutorial]
- Speed (Early it was 4 to 16 Mbps “Megabits per second” and today it is 100 to 1000 Mbps)
Wide Area Network (WAN)
- Provide long distance data transmission
- Can be complex as the backbones that connect the internet
Point-to-Point WAN – Normally a line leased from a telephone or cable TV provider that connects a home computer to internet.
Coverage – A large geographic areas that may be country, a continent or even the whole world.
Metropolitan Area Network (MAN)
Coverage – Normally town or city
High-Speed – Designed for high-speed connectivity for internet
For Example; MAN could be a part of telephone network that can provide a high-speed DSL line to the consumer.
The internet is a worldwide publically accessible network of interconnected computer networks that transmit data using the standard Internet Protocol (IP). The internet is a collection of interconnected networks linked by copper wires, fiber-optic cables, wireless connection etc.
An intranet is private network that is used in an enterprise level. It may consist of many join together LANs and also WANs. The main purpose of intranet is to share company information and resource between company workers.
An extranet can be viewed as a part of company’s intranet that is extended to users outside the company like vendors, customers, other businesses.
Peer–to–Peer – no dedicated servers are there only systems are interconnected with each other. It may be used as a client or server. All system are connected together and considered to be equal for the purpose of sharing information or devices.
Client – Server – the client/server model consists of high end servers serving clients continuously on a network by providing them specific services upon request. The servers like file server, print server, Database server and so on.
In this tutorial we have discussed brief background of networks and very simple infrastructure. I hope you like it and enjoy the history of networks. Keep learning with us.