Smartphone,Laptops,Computers, Comminication , And Network.You,Basic of Mobile,TECHNOLOGY.

Communication can be defined as the transmission of data from one place to another or from one device to another. 

When we commnicate on a network.

You can chat for hours make railway reservations,pay bills etc only if you are connected to internet.

Which is a Phones Comminica-tion & Internet based..!

Comminication. 








Basics of Computer Networks 
A computer network is a collecti-
on of two or more computers, which are connected together to share information and resources 
It is a combination of hardware and software that allows commu-
nication between computers over a network.

The computers may be connected via data communication link,like wires,cables,satellite links and other communication media.
E-mailing,instant messagi ng and web pages all are dependent on communication that take place across an underlying computer network.Networking. Network components are those major parts that are needed to install a network. Before understand that how data is transmitted on a network, it is important to know various components that compose a network. Some of them are discussed below: Client Any computer that is the part of a common network other than the server is called as client.

Servers.Any computer that hold shared files programs and the network operating systems.

Transmission Media These are the physical device through which various components of acomputer network are connected with each other such as twisted-pair cable, coaxial cable.
Protocols A set of rules is called protocols Network.protocol is standardised set of rules used for trans-mission of data and/or establish communication between them. Resources-The hardwares that are available to a computer on a particular network are known as resources.

Benefits of Networking

Computer network is very useful in modern environment.Some of the benefits of network are discussed here under.

Data and File Sharing.

Networking of computer helps theusers to share data and files.
Hardware Sharing Users can share devices such as printers, scanners,CD-ROM drives hard drives,etc.

Software Sharing

Users can share softwares within a network easily.Networkable versions of software are available at considerable savings compared to individually licenced version of the same software. 

Therefore,large companies can reduc the cost of buying software by networking their computers.

Reliabilit-You can store more than single copy of a file on various computers.it is beneficial as if the data on one computer is lost,it can be get from another computer. Thus the computers in a network, work like back-up for each other.

Network Devices.

Network devices are required to amplify the signal to restore the original strength of signal and to provide an interface to connect multiple computers in a network.

There are many types of network devices used in networking.

https://twitter.com/WorldChahat/status/1599745255644880896

Mind Maping.

..Repeater..

A repeater is a device that operates only on the physical layer of OSI model. Repeaters have two ports and can connect two segments of a LAN. It
amplifies the signals, when they are transported over a long distance so that the signal can be as strong as the original signal. A repeater boosts the
signal back to its correct level.

Hub

Hub is like a repeater with multiple ports used to connect the network channels. It acts as a centralised connection to several computers with the central
node or server. When a hub receives a packet of data at one of its ports from a network channel,it transmits the packet to all of its ports to all other network channel. It is also known as concentrator but does not amplify the incoming signals.

Gateway

A gateway is an interconnecting device, which joins two different network protocols together.They are also known as protocol converters. It accepts packet formated for one protocol and
converts the formated packet into another protocol. The gateway is a node in a network which serves as a proxy server and a firewall system and prevents the unauthorised access. It holds the information from a website temporarily, so that the repeated access to same website or web page could be directed to the proxy server instead of actual web server. Thus helps in reducing the traffic load.

Switch

It is a small hardware device that joins multiple computers together within one LAN. Switches work on the data link layer of the OSI model it.helps to reduce overall network traffic,Switch forwards a data packet to a specific route by establishing a temporary connection between the source and the destination.There is a vast difference between switch and a hub.A hub forwards each incoming packet (data) to all the hub ports,while a switch forwards each incoming packet to the specified recipient.Switches are sometimes called multiport bridges.

.Bridge.

Bridges serve a similar function as switches.A bridge filters data traffic at a network boundary. Bridges reduce the amount of traffic on a LAN by dividing it into two Segment.it operates at the data link layer of the OSI model.

Traditional bridges support one network boundary, whereas switches usually offer four or more hardware ports.

.Router.

Router is a hardware device which is designed to take incoming packets, analyse the packets ,moving the packets to another network, converting the packets to another network interface, dropping the packets,directing packets to the appropriate locations,etc.

Modem

Modem is a device that converts digital signal to analog signal (modulator) at the sender's end and converts back analog signal to digital signal (demodulator) at the receiver'send,in order to make communication possible via telephone lines. A MODEM is always placed between a telephone line and a computer. 

Types of Computer Network Computer network is broadly classified into three types: Local Area Network (LAN)LAN is a small and single site network.

A LAN connects network devices over a relatively short distance.It is a system in which computers are Local area network inter connected and the geographical area such ashome,office,buildings school may be within a building or around 1km.

Wide Area Network (WAN)

A WAN is a geographically dispersed collection of LANs.The Internet can be considered a WAN as well. A WAN like Internet,can expand most of the World.

 A network device called a router connects LANS to a WAN.

These kinds of networks use telephone lines,satellite links and other long range communication technologies to connect (as communication media) In IP networking, the router maintains both a LAN address and a WAN address Like the Internet, most WANs are not owned by any one organisation, but rather exist under collective or distributed ownership and management. WANS use technology like ATM, Frame Relay and X.25 for connectivity.

Wide area network.

Difference between LAN,MAN and WAN  Distance Limited, Unlimited Speed High,(normally Low (normally (normally 1000 MBPS) from 100 to 1000 MBPS) from 10 to100 MBPS) Media Twistedpair,Twisted pair Twisted pair cable ;Fiber cable,Fiber cable,Coaxial optic cable,optic cable cable ,Fiber Coaxial cable Nodes Normally desktops optic cable, Wireless for satellite Normally Normally desktops or desktops mini computers.

It is made up of glass or plastic and transmits signals in the form of light from a source at one end to another End art.the source,
there are either Light Emitting Diodes (LEDs) or Laser Diodes (LDs),which modulate the data into light beam using frequency modulation techniques.

Parts.
Core Protective coating Protective
coating,CoreCladdingCladding Unguided Media or Wireless Technologies It is the transfer of information over a distance without the use of enhanced electrical conductors or wires.When the computers in a network are interconnected and data is transmitted through waves,then they are said to be connected through unguided  media. 

Some commonly used unguided media of transmission are: Radiowave Transmission When two terminals communicate by using radio frequencies then such type of communication is known as radiowave transmission.This transmission is also known as  Radio Frequency (RF) transmission. Radiowaves are omnidirectional. Radiowaves are those waves that propagate in the sky mode,can travel long distances.Each computer attaches to an antenna can send and receive radiotransmission. Radiowave transmission setup has two parts:Transmitter The devices that transmits signals,are termed as transmitter.Receiver The devices that receives signals  are termed as receiver.

Microwave Transmission.

Microwaves are electromagnetic waves having frequencies range from 0.3 to 300 GHz.Microwaves have higher frequency than that of radiowaves.

1.Subnetwork Layer All the devices connected together in a local area network reside in this layer. 2. Internetwork Layer The above layer of subnetwork is, internetwork layer.This layer provides the functionality for communications between networks through gateways.
Each subnetwork uses gateways to connect to  other sub networks.
This layer is where data get transferred from gateway to gateway until it reaches its destination and then passes into the subnetwork layer. 3. Service Provider Protocol Layer This layer is responsible for the overall end-to-end communications of the network.This is the layer that runs the TCP and other protocol.handles data traffic flow and also it is responsible for message transfer. 4. Application Services Layer This layer supports the interfaces to user applications. It provides interface to 5.E-mails, remote file transfers and remote access.Many protocols are used in this layer. Services on Internet Services on Internet can be divided in following three parts:#..WWW and Website WWW and its related terms are as following. World Wide Web (WWW)was introduced on 13th March,1989.The world wide web is a system of Internet servers that supports hypertext and multimedia to access several Internet protocols on single interface.The world wide web is often abbreviated as the web or www.The world wide web is a way of exchanging information between computers on the Internet,try to tie them together into a vast collection of interactive multimedia resources.
The Internet is a huge ocean of information of resources and services such as interlinked hypertext documents of World Wide Web (WWW) 
online chatting,online banking, file transfer an sharing,online gathering, online education .

History of Internet.In 1969, the university of California at Los Angeles,the University of Utah and some other universities were connected as the beginning of the ARPANET (Advanced Research Projects Agency Network) using 50 kbits circuits.The goal of this project was to connect computers at different universities and US  mid 80's another federal agency,the National Science Foundation Created a new high capacity network called NSFnet, which was more capable than ARPANET.

The only drawback of NSFnet was that it allowed only academic research on its network and not any kind of private business on private organisations and people started working to build their own networks,which were later interconnected with ARPANET and NSFnet to form the Internet.

Basics of Internet Architecture
Internet is a global system of interconnected networks.

It consists of multiple networks in which LANs are attached to other LANs,other communication networks, remote sites, individual stations and WANs. 

The architecture of Internet is hierarchical in nature..!
@$elfyr.