ppti.info Technology Wifi Technology Pdf


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Contents. ❖ Introduction. ❖ Wi-Fi Technology. ❖ Wi-Fi Network Elements. ❖ Wi-Fi Network Topologies. ❖ Hotspots. ❖ How a Wi-Fi Network Works. ❖ Advantages. the WLAN, that's plus comparing WiFi with other technologies, for example 3G and open-standard technology that enables wireless connectivity between. PDF | Computer networks have played a major role in expanding the operational WiFi is a perfect example of one of these emerging technologies, which has.

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describing the characteristics of a wireless Local Area Network. The term Wi-Fi suggests Wireless Fidelity, resembling the long- established audio-equipment. Permission may be sought directly from Elsevier's Science & Technology Rights. Department in Oxford The Diversity of Wireless Networking Technologies. Wi-Fi® is a registered trademark of the Wi-Fi Alliance Benefits of Wi-Fi. pany that focuses on the business implications of technology change, has.

Organizations and businesses , such as airports, hotels, and restaurants, often provide free-use hotspots to attract customers. Enthusiasts or authorities who wish to provide services or even to promote business in selected areas sometimes provide free Wi-Fi access.

Routers that incorporate a digital subscriber line modem or a cable modem and a Wi-Fi access point, often set up in homes and other buildings, provide Internet access and internetworking to all devices connected to them, wirelessly or via cable.

Similarly, battery-powered routers may include a cellular Internet radio modem and Wi-Fi access point. When subscribed to a cellular data carrier, they allow nearby Wi-Fi stations to access the Internet over 2G, 3G, or 4G networks using the tethering technique.

Many smartphones have a built-in capability of this sort, including those based on Android , BlackBerry , Bada , iOS iPhone , Windows Phone and Symbian , though carriers often disable the feature, or charge a separate fee to enable it, especially for customers with unlimited data plans.

Some laptops that have a cellular modem card can also act as mobile Internet Wi-Fi access points.

What is WiFi and How Does it Work?

Wi-Fi also connects places that normally don't have network access, such as kitchens and garden sheds. Google is intending to use the technology to allow rural areas to enjoy connectivity by utilizing a broad mix of projection and routing services. Google also intends to bring connectivity to Africa and some Asian lands by launching blimps that will allow for internet connection with Wi-Fi technology. A company called WiFiyNet has set up hotspots in Mysore, covering the complete city and a few nearby villages.

Officials in South Korea's capital Seoul are moving to provide free Internet access at more than 10, locations around the city, including outdoor public spaces, major streets and densely populated residential areas. Carnegie Mellon University built the first campus-wide wireless Internet network, called Wireless Andrew , at its Pittsburgh campus in before Wi-Fi branding originated.

Many universities collaborate in providing Wi-Fi access to students and staff through the Eduroam international authentication infrastructure. Ad hoc versus Wi-Fi direct[ edit ] Wi-Fi also allows communications directly from one computer to another without an access point intermediary. This is called ad hoc Wi-Fi transmission. This wireless ad hoc network mode has proven popular with multiplayer handheld game consoles , such as the Nintendo DS , PlayStation Portable , digital cameras , and other consumer electronics devices.

Some devices can also share their Internet connection using ad hoc, becoming hotspots or "virtual routers". Countries apply their own regulations to the allowable channels, allowed users and maximum power levels within these frequency ranges.

The ISM band ranges are also often used. In this frequency band equipment may occasionally suffer interference from microwave ovens , cordless telephones , USB 3. Spectrum assignments and operational limitations are not consistent worldwide: Australia and Europe allow for an additional two channels 12, 13 beyond the 11 permitted in the United States for the 2. In the US and other countries, A standard speed Wi-Fi signal occupies five channels in the 2. Any two channel numbers that differ by five or more, such as 2 and 7, do not overlap.

The oft-repeated adage that channels 1, 6, and 11 are the only non-overlapping channels is, therefore, not accurate. Channels 1, 6, and 11 are the only group of three non-overlapping channels in North America. However, channels that are four apart interfere a negligible amount, much less than reusing channels.

The 5GHz bands are absorbed to a greater degree by common building materials than the 2. As the The data is organized into The base version of the standard was released in , and has had many subsequent amendments.

The standard and amendments provide the basis for wireless network products using the Wi-Fi brand. While each amendment is officially revoked when it is incorporated in the latest version of the standard, the corporate world tends to market to the revisions because they concisely denote capabilities of their products.

In addition to These are required because Ethernet's cable-based media are not usually shared, whereas with wireless all transmissions are received by all stations within range that employ that radio channel. Therefore, accurate transmission is not guaranteed so delivery is therefore a best-effort delivery mechanism.

For internetworking purposes Wi-Fi is usually layered as a link layer equivalent to the physical and data link layers of the OSI model below the internet layer of the Internet Protocol. This means that nodes have an associated internet address and, with suitable connectivity, this allows full Internet access. Performance[ edit ] Parabolic dishes transmit and receive the radio waves only in particular directions and can give much greater range than omnidirection antennas Yagi-Uda antennas , widely used for television reception, are relatively compact at Wi-Fi wavelengths See also: Long-range Wi-Fi Wi-Fi operational range depends on factors such as the frequency band, radio power output , receiver sensitivity, antenna gain and antenna type as well as the modulation technique.

In addition, propagation characteristics of the signals can have a big impact. At longer distances, and with greater signal absorption, speed is usually reduced. Transmitter power[ edit ] Compared to cell phones and similar technology, Wi-Fi transmitters are low power devices. To reach requirements for wireless LAN applications, Wi-Fi has higher power consumption compared to some other standards designed to support wireless personal area network PAN applications.

For example, Bluetooth provides a much shorter propagation range between 1 and m [65] and so in general have a lower power consumption. Other low-power technologies such as ZigBee have fairly long range, but much lower data rate. The high power consumption of Wi-Fi makes battery life in some mobile devices a concern. Antenna[ edit ] An access point compliant with either Higher gain rating dBi indicates further deviation generally toward the horizontal from a theoretical, perfect isotropic radiator , and therefore the antenna can project or accept a usable signal further in particular directions, as compared to a similar output power on a more isotropic antenna.

Note that this assumes that radiation in the vertical is lost; this may not be the case in some situations, especially in large buildings or within a waveguide. On wireless routers with detachable antennas, it is possible to improve range by fitting upgraded antennas which have higher gain in particular directions. Outdoor ranges can be improved to many kilometers through the use of high gain directional antennas at the router and remote device s.

Multiple antennas enable the equipment to focus on the far end device, reducing interference in other directions, and giving a stronger useful signal. This greatly increases range and network speed without exceeding the legal power limits. IEEE Wi-Fi in the 2. Under optimal conditions, IEEE Radio propagation[ edit ] With Wi-Fi signals line-of-sight usually works best, signals can transmit, absorb, reflect, and diffract through and around structures.

The data being transmitted is superimposed on the radio carrier so that it can be accurately extracted at the receiving end. This is generally referred to as modulation of the Carrier by the information being transmitted. Once data is superimposed modulated unto the radio carrier, the radio signal occurs more than a single frequency ,since the frequency or orbit rate of the modulating information adds to the carrier. Multiple radio carriers can exist in the same space at the time without interfering with each other, if the radio waves are transmitted or different radio frequencies.

To extract data, a radio receiver tunes in One radio frequency while rejecting all other frequencies. At a minimum, the access point receives, buffers, and transmits data between the wireless LAN and the wired network infrastructure. The access point or the antenna attached to the access point is usually mounted high but may be mounted essentially any where that is practical as long as the desired radio coverage is obtained.

End users access wireless LAN through wireless LAN adapters, which are implemented as PC cards in notebooks or palmtop computers, as cards in desktop computers or integrated within handheld computers. Wireless LAN adapters provides an interface between the client network operating system NOS and the air waves via an antenna.

There are four steps involved in setting up a wireless network 1 Choose the wireless network equipment. Service pack 2 also helps protect one against hackers, worms and other Internet intruders.

As one is looking for products in stores or on the Internet, you might notice that you can choose equipments that supports three different wireless networking technologies: A router connects to the server that host the Internet and network resources. This is the base station where all computers , wireless and cabled are connected through the router and access hubs.

This LED connection to the power blinks during data transmission supply Fig 3. If one have a newer computer; one may already have wireless capability in-built. If this is the case, then there is no need for wireless network adapter.

If there is a need to purchase an adapter for a desktop computer, a USB wireless network adapter is recommended. The laptop has no wireless adapter, the PC card base network adapter can be purchased and installed. Make sure that there is one adapter for every computer on your network wireless. To make setup easy, choose a network adapter made by the same manufacturer. As that of the wireless router. For example, if you find a good price on the D-link Router, choose a D-link network adapter to go with it.

To make shopping even easier, buy a bundle, such as those available from the D-link, Netgear, linksys, and Microsoft. If one does not have any USB ports buy a hub to have additional ports. Your modem should stay connected directly to the Internet. Later, after you have hooked everything up, your computer will wirelessly connect to your router and the router will send communication through your modem to the Internet.

The instructions below apply to a link sys wireless router. The ports on the router may be labelled differently, and the images may look different on your router. If you currently have your computer connected directly to your modem; unplug the network cable from the back of your computer, and plug it into the port labelled Internet, WAN, or WLAN, or WLAN on the back of your router.

If you do not currently have a computer connected to the Internet: If you currently have your computer connected to a router: Then, unplug any other network cables, and plug them into any available ports in your wireless router. Next; plug in and turn on the cable or DSL modem. Wait a few minutes to give it time to connect to the Internet, and then plug in and turn on the wireless router. Next, open Internet Explorer and type in the address to configure the router.

You might be prompted for a password; the address and password used will vary depending on what type of router you have, so refer to the instructions included with the router.

As a quick reference, this table shows the default address, usernames, and passwords for some common router manufactures. Table 3. Most of the default settings should be fine.

WiFi Technology Seminar PPT with pdf report

But you should configure three things. You should choose something unique that of your neighbors will be using. For most routers, you will provide a pass phrase that the router uses to generate several keys. Make sure the pass phrase is unique and long you do not need to memorizes it. The exact step you follow to configure this settings will vary depending on the type of router you have.

After each configuration setting, be sure to click save settings, apply or Ok to save your changes. Now you can disconnect the network cable from your computer.

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Windows XP will automatically detect the new adapter, and may prompt you to insert the CD that comes with the adapter. The on-screen instructions will guide you through the configuration process. The steps below only apply while using Windows XP service Pack 2. Windows XP should show an icon with a notification that says it has found a wireless network. Follow these steps to connect the computers to the wireless network. If you run into any problems, consult the documentation that came with your network adapter.

Do not be afraid to call their technical support. If the network fails to appear, click refresh network list in the upper left corner. Click the network and then click connect in the lower right corner. Types the encryption key that you wrote down earlier in both the network key and confirm network key boxes, then click connect.

After you are connected ,you can now close wireless network connection window. Enter IP Admin, admin. Click tab interface setup shown below: Click save button.

Learn Wireless Basics

One user is allowed to access the Wi-Fi service from this access point. Important key point to prevent misuse of Wi-Fi facility by unauthorized user: Select Disable to allow all wireless computers to communicate with the access point without any data encryption. Key 1-key 4: The WEP keys are used to encrypt data. If you choose bit WEP, then enter any 5 character each key If you choose bit WEP, then enter 13 characters for each key The values must be set-up exactly the same as the access point as they are in the wireless client station.

Use the drop down list box to enable or disable MAC address filtering. MAC addresses not listed will be allowed to access the router. One should always use Wi-Fi facility with activating the security features. It is best to use the same computer that is connected to the modem for configuring the DI multimode wireless router.

C Insert an Ethernet cable to LAN port 1 on the back panel of the DI and an available Ethernet port on the network adapter in the computer to be used to configure the DI router. D Computers equipped with Fig 3. Then press the enter or return key The log on pop-up screen will appear.

Once you have logged in, the home screen will appear. Set up your new password. Choose your time zone from the drop down list. Select your Internet connection. You will be prompted to select the type of Internet connection for the router. If you selected Dynamic IP address, the screen will appear: Used mainly for cable Internet service. Wireless setup-the default wireless settings for the IEEE. If you wish to use encryption for the IEEE By default, the encryption is disabled.

The setting is complete! At its most basic, two PCs equipped with wireless adapter cards can set up an independent network whenever they are within range of one another. This is called a Peer-to-Peer network. On-demand networks such as in this example require no administration or pre-configuration. In this case each client would only have access to the resources of the other client and not to a central server. Since the access point is connected to the wired network each client would have access to server resources as well as to other clients.

Each access point can accommodate many clients; the specific number depends on the number and nature of the transmissions involved. Many real-world applications exist where a single access point services from client devices. In a very large facility such as a warehouse, or on a college campus it will probably be necessary to install more than one access point. Access point positioning is accomplished by means of a site survey.

The ability of clients to move seamlessly among a cluster of access points is called roaming. Access points hand the client off from one to another in a way that is invisible to the client, ensuring unbroken connectivity. Extension Points look and function like access points, but they are not tethered to the wired network as are APs.

EPs function just as their name implies: EPs may be strung together in order to pass along messaging from an AP to far-flung clients, just as humans in a bucket brigade pass pails of water hand-to-hand from a water source to a fire.

One solution might be to install a directional antenna on each building, each antenna targeting the other. The antenna on A is connected to your wired network via an access point. The antenna on B is similarly connected to an access point in that building, which enables wireless LAN connectivity in that facility.

Wireless LAN configurations range from simple peer-to-peer topologies to complex networks offering distributed data connectivity and roaming. Besides offering end- user mobility within a networked environment, wireless LANs enable portable networks, allowing LANs to move with the knowledge workers that use them. Every node on a network requires its own IP address.

On a network, IP address can be divided into two portions: The network address are shared by all the nodes on that network. The host address is unique to that node. There are 32 bits in every IP address. Possible address.

One might think that 4 billion IP addresses would be enough for a world of just over 6 billion people. Although not all IP address is engaged at once, all available IP address are taken. D IP address between E IP address between Why is broadband better than dial up? There is an easy answer to this question. It is fast and always on.

There is no need to dial up or reconnect down streams speeds are as high as 2mbps or more. However, there are many broadband technologies such as satellite available where cable and DSL are not found. Below are two sections involved in the installation and setup of broadband connections. Each computer is able to send and receive data over the network cabling.

The hub sends this data to all of the computers on the network and a switch would direct it only to the correct computer. A switch can do two jobs at the same time, sending and receiving data which is a speed bonus. However, if the computer tries to access the Internet, which is one huge network some times referred to as a WAN — wide area network , we would have computers exposed to the whole world, and the network would simply not work with this type of set up.

It translates the Internet request from each computer on our network into a special format for the Internet servers.


It acts like a sort of bridge, directing only Internet traffic from our network to the Internet and back again routing , keeping internal network traffic separate from the Internet traffic. Receptor for original default factory setting power adapter Fig 4. The network data is in the correct format but we need to send this information down the telephone line at as high a speed as is possible. The device which does this is the modem.The wide spread reliance on networking in business and geometric growth of the internet and on line services points to shared data and resources with a wireless fidelity Wi-fi ,network users can have access to the internet , share network resources at fixed or mobile terminals.

Click tab interface setup shown below: These wavelengths work best for line-of-sight. If there is enough signal between nodes, they should connect.

If there are areas that are then left out, how will those areas be included in the network? However, channels that are four apart interfere a negligible amount, much less than reusing channels.

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