Wireless Network Kya Hai

Wireless Network kya Hai...(Wi-Fi)

 

Hi Friends Aaj main aap logo ko  wireless Network ke bare me batane ja rha hoon. And I hope ke aap logo ko ye samaj me aa jayega. wireless network kya hota, Aur uska use kaise kiya jata hai.wireless Network Ek prakar ka bina wire ke chalye jane bala device hota hai. Dosto main aap logo ko ye bahut hi important cheez batane ja raha hun. Wireless ya Koi bhi Concept janne se Pahle aap logo ko Uske Terms  ke bare me pata hona Chahiye. Agar Hum Uske Term ke bare me Jante hai to hum Use Concept ko Bade Aasani se Samaz sakte hai.

Wi-Fi Network kya Hota hai or Ise Computer Or Mobile se kaise Connect karte hai..?  

Dear Friends agar aap log chahte hai, ki aapke mobile me bhi free internet chale. To main aapko batata hun ki kaise wi-fi se free me internet chalaye to ye blog jaroor pade aapko mai inetrnet ke baare me or bhi bahut saari information de sakta hoo to chaliye hum jante hai ki kaise free me wifi se internet use kaise karte hai .  

 

Wi-Fi se kaise chalaye free me internet

   

Wi-Fi se free internet chalane ke step by step aasan Tareeke.

Step:1) Apka mobile aapke pass hi hoga aisa mai janta to nhi but manta hoon. to sabse pahle jo aapke screen ka HOME button ho vaha per click kare . 

Step:2) ab aapke mobile me bahot saare menu open ho gaye hoge, jaise ki Massage, Contact, PlayStore, E-Mail Hoga Setting Bhi Hogi . to ab setting ke menu per click karte hai.

Step:3) Jb aap setting per click karege to apke saamne kuch aise naam ayege jo main niche dikha raha hoon, 

Call setting                                         
Display 

Location & secuirity

Sound 

Step:4) Ab aapke samne WiFi setting kar ke naam hoga  aap waha par click keejiye.

Step:5) wi fi naam hoga aap  us par click kare ab box me right ka Mark Tick ho gaya hoga.

Tick karne  ke baad aapke saamne kai saare naam aa jayege jis kisi ka bhi wifi on hoga automaticlly aapke mobile se connect ho jayega .

Example  niche aise naam show karege jaise ki unique computer hai to unique naam ayega bus aapko us naam per click karna hai. Aapke bahut se dost ek sath ke aap ke mobile se bhi  wifi connect kar sakte hai. main aapko kuch example batata hoon ki wi-fi koun koun se device se connect hota hai .

                                          1. MOBILE
                                          2.TABLETS   

                                          3.LAPTOP
                                          4.COMPUTER

Aise Bahut Se android version bale mobile phone computer se wi-fi connect hota hai or aap free me inetrnet ka laabh utha sakte hai. or haa kisi ne wi-fi device per ager  security code dala hua hai to apka wifi kisi bhi mobile ya computer se connet nahi hoga agar aapko wi-fi ka code pata hai tabhi aap code type karke internet free use kar sakte hai.

  Dosto Aap logo ko humari Post acchi lagi ho to humara
E-mail jaroor subscribe kare. or apne sabhi Dosto ko bhi is website ke bare me jaroor bataye. ager apko koi bhi problem create hoti hai to pls aap humse comment kar ke puch  sakte hai.

...........................................Thank You..............................................

 

                                        

 

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Wide Area Network (WANs)

Wide Area Network:- 

A Wide Area Network or WAN, spans a large geographical area, often a country or continent. It contains a collection of machines intended for running user (i.e. application) programs. we will follow traditional usage and call these machines hosts. the term and system is sometimes also used in the literature. The host are connected by a communication subnet, or just subnet for short. The job of the subnet is to carry message from host to host. just as the telephone system carries words from speaker to listener. by separating the poor communication aspects of the network (the subnet) from the application aspects (the hosts), the complete network design is greatly simplified. 

    In most Wide Area Networks, the subnet consists of two distinet components: transmission lines and switching elements, Transmission lines (also called circuits, channel or trunks) move bits between machines. 

   The switching elements are specialized computers used to connect two or more transmission lines. when data arrive on an incomeing line, the switching element must choose an outgoing line to forward them on. unfortunately, there is no standard terminology used to name these computers. They are variously called packet switching nodes, intermediate systems, and data switching exchanges, among other things. as a generic term for the switching computers, we will use the word router, but the reader should we aware that no consensus on terminology exists here. In this model shown in figure second, each host is generally connected to a LAN on which a router is present, although in some cases a host can be connected directly to a router. The collection of communication lines and routers (but not the hosts) from the subnet.

   An aside about the "subnet" is worth making. originally, its only meaning was the collection of routers and communication lines that moved packets from the source host to the destination host. however, some years later, it also acquired a second meaning in conjuction with network addressing (which we will discus in chap). Hence the term has a certain ambiguity about it. unfortunately, no widely-used alternative existe for its initial meaning, so with some hesitation we will use it in both senses. From the context, It will always be clear which is meant.

  In most WANs the network contains numerous cables or telephone lines, each one connecting a pair of routers. If two routers that do not share a cable nevertheless wise to communicate, they must do this indirectly, via other routers. when a packet is sent from one router to another via one or more intermediate routers, the packets is received at each intermediate routers in its entirety, stored there until the required output line is free and then forwarded. A subnet using this principle is called a point-t-point, store and forward, or packet switched subnet. Nearly all wide area Networks (aspect those using sattelites) have store- and forward subnets. When the packets ae small and all the same size, they are often called cells.

 When a point-to-point subnet is used, an important design issue is what the router interconnection topology should look like. Figure Third Shows several possible topologies. Local networks that were designed as such usually have a symmetric topology. In Contrast, wide Area networks typically have irregular topologies.

     A second possibility for a wan is a satellite or ground radio system. Each router has an antenna through which it can send and receive. All routers can hear the output from the satellite, and in some cases they can also here the upward transmission of there follow routers to the satellite as well. sometimes the routers are connected to a substantial point-to-point subnet, with only some of them having a satellite antenna. Satellite networks are inherently broadcast and are most useful when the broadcast property is important....

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Metropolitan Area Networks (MAN) The Parts Of Network Hardware

Metropolitan Area Networks:- 

Metropolitan Area Network, or Man (plural: MANs, not MEN) is basically a bigger version of a 

LAN and normally uses similar technology. It might cover a group of nearby corporate offices or a 

city and might be either private or public.A MAN can support both data and voice, and might even 

be related to the local cable television network. A MAN just has one or two cables and does not 

 contain switching elements, which shunt packets over one of several potential output lines. Not 

having to switch simplifies the design.

  The main reason for even distinguishing MANs as a special category is that a standard has been 

adopted for them, and this standard is now being implemented. It is called DQDB (Distributed 

Queue Dual Bus) or for people who prefer numbers to letters, 802.6 (the number of the IEEE 

standard that defines it). DQDB consists and two unidirectional buses (cables) to which all the 

computers are connected, as shown in Second Figure. Each bus has a head-end, a device that 

initiates transmission activity. traffic that is destined for a computer to the right of the sender uses 

the upper bus. Traffic to the left uses the lower one.

   A key aspect of a MAN is that there is a broadcast medium (for 802.6, two cables) two which all 

the computers are attached. This greatly simplifies the design compared to other kinds of 

networks. we will discuss DQDB in more detail in chap.

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Local Area Networks (LAN) Parts Of Network Hardware

Local Area Networks:- 
  

Local Area Networks, generally called Lans,are privately-owned networks within a single building 

or campus of up to a few kilometers in size. they are widely used to connect personal computers

and workstation in company offices and factories to share resource (e.g; printers) and exchange 

information. Lans are distinguished from other kinds of networks by three characteristice: (1) their size, (2) their transmission technology, and (3) there topology.

    

    LANs are restricted in size, which means that the worst-case transmission time is bounded and 

known in advance. knowing this bound makes it possible to use certain kinds of design that would 

not otherwise be possible. it also simplifies network management.

    

    LANs often use a transmission technology consisting of a single cable to which all the machine 

 

are attached, like the telephone company part lines once used in rural areas. Traditional LANs run at speed of 10 to 100 Mbps, have low delay (tens of microseconds), and make very few 

 

errors. Newer LANs may operate at higher speeds, up to hundreds of megabits/sec. in this book, 

we will adhere to tradition and measure line speeds in megabits/sec (Mbps), not megabytes/sec 

(MB/Sec). A Megabit is 1,000,000 bits, not 1,048,576 (2`20) bits.

Various Topologies are possible for broadcast LANs. First Figure shows to of them. In a bus (i.e; 

liner cable) network, at any instant one machine is the master and is allowed to transmit. All other 

machines are required to refrain from sending. An arbitration mechanism is needed  to resolve 

conflicts when two or more machines want to transmit simultaneously. the arbitration mechanism 

may be centralized or distributed . IEEE 802.3, popularly called Ethernet Tm , For example, is a 

bus based broadcast network with decentralized control operating at 10 or 100 Mbps. Computers 

on an Ethernet can transmit whenever they want to; if two or more packets collide, each computer 

just waits a random time and tries again later. 

   A second type of  broadcast system is the ring. In a ring, each bit propagates around on its own, 

not waiting for the rest of the packets to which it belongs, Typically, each bit circumnavigates the 

entire ring in the time it takes to transmit a few bits, often before the complete packet has even 

transmitted, Like all other broadcast system, some rule is needed for arbitrating simultaneous 

accesses to the ring. Various methods are in use and will be discussed later in this book. IEEE 

802.5 (the IBM token ring), is a popular ring-based LAN operating at 4 and 16 Mbps.

  Broadcast networks can be further divided into static and dynamic, depending on how to channel 

is allocated. A typical static allocation would be to divide up time in to discrete intervals and run a 

round robin algorithm, allowing each machine to broadcast only when its time slot comes up. Static 

allocation wastes channel capacity when a machine has nothing to say during its allocated slot, so 

most systems attempt to allocate the channel dynamically (i.e. on demand).

 Dynamics allocation methods for a common channel are either centralized or decentralized. In the 

centralized channel allocation method, there is a single entity, for example a bus arbitration unit, 

which determines who goes next. It might to this by accepting requests and making a decision 

according to some internal algorithm. In the decentralized channel allocation method, there is no 

central entity; each machine must decide for itself whether or not a transmit. You might think that 

this always leads to chaos, but it does not. Later we will study many algorithms design to bring 

order out of the potential chaos. 

    The other kind of of LAN is built using point-to point lines. individual lines connect a specific 

machine. Such a LAN is really a miniature wide area network. We will look at these later.  

 

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What Is Part Of Network Hardware

Network Hardware:- 

It is now time to turn our attention from the applications and social aspects of networking to the 

technical issues involved in network design. there is no generally accepted taxonomy in to which 

all computers networks fit, but two dimension stand out as important: transmission technology and scale. we will now examine ease of these in turn.

    Broadly speaking, there are two types of transmission technology:

1- Broadcast Networks.

2- Point-To-Pont Networks.  

Broadcast networks have a single communicaton channel that is shared bu all the machine on the 

network. short messages, called packets in certain contexts, sent by any machine are received by 

all the others. an address and field within the packets specifies for whom it is intended. upon 

receiving a packet, a machine checks the address field. if the packets is intended for itself, it 

processes the packets; if the packets is intended for some other machine, it is just ignored.

     As an analogy, consider someone standing at the end of of a corridor with many room off it and 

shouting "Watson, come here. i want you." Although the packet may actually be received (heard) 

by many people, only Watson responds. The others just ignore it. another example is an airport 

announcement asking all flight 644 passengers to report to get 12.

   Broadcast system generally also allow the possibility of addressing a packets to all destinations 

by using a special code in the address field. when a packet with this code is transmitted, it is 

received and processed by every machine on the network. this mode of operation is called 

broadcasting. some broadcast system also support transmission to a subset of the machines, 

something known as multicasting. one possible scheme is to reserved one bit to indicate 

multicasting. The remaining n-1 address bits can hold a group number. Each Machine can 

"Subscribe" to any or all of the groups. when a packet is sent to a certain group, it is delivered to 

all machine subscribing to that group.

   In contrast, point to point networks consist of many connections between individual pairs of 

machine. to go from the source to the destination, a packet on this type of network may have to 

first visit one or more intermediate machines.

  Often multiple routs of different lengths are possible, so routing algorithms play in important role 

in point-to-point networks. as a general rule (although there are many exceptions) smaller, 

geographycally localized networks tend to use broadcasting, whereas larger networks usually are point-to-point.

     An alternative criterion for classifying networks is there scale. In Figure 2nd we give a 

classification of multiple processors system arranged by there physical size. At the top are data 

flow machines, highly parallel computers with many functional units all working on the same 

program. Next come the multicomputers, system that communicate by sending messages over 

very short, very fast buses. Beyond the multicomputers are the true networks, computers that 

communicate by exchanging message over longer cables. These can be divided in to local, 

metropolition, and wide area networks. finally the connection of two or more networks is called an 

internetwork. The world wide internet is a well known example of an internetwork. Distance is 

important as a classification metric because different techniques are used at different scales. In 

this book we will be concerned with only the true networks and their interconnection. below we 

give a brief introduction to the subject of networkhardware.... 

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Uses Of Computer Networks Part 3rd

Social Issues:-

The widespread introduction of networking will introduce new social, ethical, political problems 

(Loudan, 1995). Let us just briefly mention a few for them; a through that study will require a full 

book, at least. a popular feature of many networks are newsgroups or bulletin boards where 

people can exchange messages with-like minded inviduals. as long as the subjects are restricted to technical topics or hobbies like gardening, not to many problems will arise.
  
     The trouble comes when newsgroups are set up on topics that people actually care about, like 

politics, religion, or sex. views posted to such groups may be deeply offensive to some people. 

Furthermore, message need to be limited to text. High resolution colour photographs and even 

short video clips can now easily be transmitted over computer networks. some people take a live 

and let live view but others feel that posting certain material (e.g., child pornography) is simply unacceptable. Thus the debate rages.

   People have sued network operators, climbing that they are responsible for the contents of what 

they carry, just as newspaper and magazines are. The inevitable response is that a network is like 

a telephone company or the post office and can not be expected to police what its users say. 

stronger yet, having network operators censor message would probably causes them to delete 

everything with even the slightest possibility of their being sued, and thus violate there users' rights to free speech. it is probably safe to say that this debate will go on for a while.

 Another fun area is employee rights versus employer rights. Many people read and rights. Many 

people read and write email at work. Some employers have claimed that right to read and possibly 

censor employee message, including message sent from a home terminal after work. not all 
employees agree with this (sipior and Ward, 1995). 

   Even if employers have power over employees, does this relationship also govern universities 

and students. how about high school and students. In 1994, Carnige-Mellon university decided to 

turn off the incoming message stream for several newsgroups dealing with sex because the 

university felt the material was inappropriate for minors (i.e.those few student under 18). the fallout from this event will take years to settle.

  Computer Networks offer the potential for sending anonymous message. In some situation, this 

capability may be desirable, for example, it provides a way for students, soldiers, employees, and 

citizens to below the whistle on illegal behavior on the part of professors, officers, superiors, and 

politicians without fear of reprisals. on the others hand, in the united states and most other 

democracies, the law specifically permits an accused person the right to the confront and challenge his accuser in court. anonymous assusations cannot be used as evidence.

  In Short, computer networks, likes the printing press 500 year ago, allow ordinary citizens to 

distribute their views in different  audiences then were previously possible. This new-found 

freedom brings with it many unsolved social, political, and moral issues. The solution to these problems is left as an exercise for the reader.....   

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Uses Of Computer Network part 2nd

Networks For People:- 

 

 

The Motivation given above for building for computer networks are all essentially economics and 

technological in nature. if sufficiently large and powerful mainframes were available at  acceptale

prices most company would simply choose to keep all there data on them and give employees 

terminals connected to them. in the 1970s and early 1980s, most companies operated this way.

 comfferd a huge price/performance advantage over mainframes..

      Starting in the 1990s, computer network began to start delivering service to private individuals

 at home. these service and the motivation for using  them are quite defferent then the "corporate 

efficiency" model described in the previous section below we will sketch three of the more exciting ones that are that starting to happen.

1-Acces to remote information 

2-Person to Person communication 

3-Interactive entertainment  

 Access to remote information will come in many forms. One area in which it is already happening

 is access to financial institution. Many people pay there bills, manage there bank accounts, and 

handle there investment electronically. Home shopping is also becoming popular, with the ability

to inspect the online cat-logs of thousands of companies some of these catlogs will soon provide the ability to get an instant video an any product by just clicking on the product`s name.

     Newspaper will go online and personalized. It Will be possible to tell the newspaper that you 

want everything about corrupt polticians big fires, scandals invobing celebrities, and epidemics, but 
no football, thank you at night while you sleep the newspaper will be downloaded to your 

computers disk or printed on your laser printer on a small scale this service already exists.the 

next step beyond newspaper (plus magazines and scientific journals) is the on-line digital library. 

depending on the coast, size, and weight of book-sized notebook computers, printed books may

 become obsolete. skeptics should take notes of the effect the printing press had on the medieval illuminated manuscipet. 

    Another application that falls in this category is access to information systems like the current

 world wide web, which contains information about the art business, cooking, government, health, 

history, hobbies, recreation, science, sports, travel, and too many other topics to even mention.

    All of the above applications involve interactions between a person and a remote database. the 

second board category of network use will be person-to-person interaction, basically the 21st 

century answer to the 19th century tele-phone. Electronic Mail or Email is already widely used by

millions of people and will soon routinely contain audio and video as well as text. smell in messages will take a bit longer a perfect.

   Real-time email will allow remote users to communicate with no delay, possibly seeing and

 hearing each other as well as. this technology makes it possible to have virtual meetings, called 

video conference, among far-flung people. it is sometimes said that transportation and 

communication are having a race, and which ever wins will make the other obsolete. virtual 

meetings could be used for remote school, getting medical opinions from distant specialists, and numerous other applications.

  Worlwide newsgroups, with discussions on every conceivable topic are already commonplace

 among a select group of people, and this will grow to including the population at large. these 

disussions, in which one person posts message and all the other subscribers to the newsgroups can
 read it, run the gamut from humorous to impassioned.

  Our third category is entertainment, which is a huge and growing industry. The killer applications

 here (the one that may drive all the rest) is video on demand. a decade or so hence, it may be

 possible to select any movie or televisions program ever made, in any country, and have it 

displayed on your screen instantly. New films may become interactive, where the users is 

occasionally prompted for the story direction (should macbeth murder Duncan or just bide his 

time) with alternative scenarios provided for all cases. live television may also become interactive, with the audience participting in quiz shows, choosing among contestant, and so on.

   On The Other Hand, May be the killer application will not be video on demand maybe it will be 

game playing. already we have multiperson real time simulaton games, like hide and seek in a 

virtual dungeon, and flight simulators with the players on one team trying to shoot down the 

players on the opposing team.I done With Goggles and three dimensional real time, Photogaphics-

quality moveing images, we have a kind of wordwide shared virtual reality.
   
  In Short, The ability to merge information, communication and entertainment will surely give rise 

to a massive new industry based on computer networking.

   

      

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Uses Of Computer Networks

Uses Of Computer Networks:- 

Before we start to examine Technical issues in detail, it is worth devoting some time to pointing

 out why people are intrested in computer networks and what they can be used for.

Networks For Companies:- 

Many organizations  have a substantial number of computers in operation, often located far apart 

For example a company with many factories may have a computer at each location to keep track 

of inventories monitor productivity and do the local payroll. intially each of these computers may 

have worked in isola-tion from of others but at some point managment may have decided to 

connect them to be able to extract to and correlate information about the entire company.

       Put in slightly more general from, the issue here is resource sharing  and the goal is to make 

all programs equipment and especially data available to anyone on the network without regard to

 the physical location of the resource and the users. in other words the mere fact that a user 

happens to be 1000 km away from his data should not prevent him from useing the Data as though

 they were local. This goal may be summarized by saying that it is an attempt to end the "tyranny of geography." 

      A Second Goal is to provide High reliability by having alternative source of supply. for 

example all files could be replicated on two or three machine so if one of them is unavailable (due

 to a hardware failure), the other copies could be used. In addition the presence of multiple CPUs 

means that if one goes down the others may be able to take over its work, although at reduced 

performance. for military baking air traffic control nuclear reactor safety and many other 

applications the ability to continue operating in the face of hardware problems is of utmost importance.

    Another Goal is saving money. small computers have a much better price/performance ratio 

then large ones. Mainframes (room size computers) are roughly a factor of then faster then 

personal computers, but they cost a thousand times more. This imbalace has caused many systems

 desiners to build system consisting of personal computers one per user with data kept on one or 

more shared file server machines. in this model the users all called clients and the whole

arrangement is called the client-server model. It is illustrated in fig. 1-1.

   In the client-server model, communication generally takes the from of a request message from 

the client to the server asking for some work to be done..

 

 

The server then does the work and sends back the reply. usually, there are many clients using a small number of servers.

     Another networking goal is scalabilty, the ability to increase system performance gradually as

the workload grows just by adding more processors. With centralized mainframes, when the 

system is full it must be  replaced by a larger one, usually at great expense and even greater

 disruption to the users. with the client-server model, new clients and new servers can be added as needed.

    Yet another Goal of setting up a computer network as little to do with technology at all a 

computer can provide a powerful communication  medium among widely separated employees   

  Using a network, it is easy for two or more people who live for apart to write a report together. 

when one worker makes to change to an online document, the others can see the change 

immediately, insted of waiting several days for a latter. such a speedup makes impossible. In the

long run, the use of networks to enhance human to human communication will probably prove 

more important then technical goal such as improved reliability....

 

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