computer science crazy|
Joined: Dec 2008
21-09-2008, 11:47 AM
Wi-Fi, or Wireless Fidelity is freedom :it allows you to connect to the internet from your couch at home, in a hotel room or a conferance room at work without wires . Wi-Fi is a wireless technology like a cell phone. Wi-Fi enabled computers send and receive data indoors and out; anywhere within the range of a base station. And the best thing of all, it is fast.
However you only have true freedom to be connected any where if your computer is configured with a Wi-Fi CERTIFIED radio (a PC card or similar device). Wi-Fi certification means that you will be able able to connect anywhere there are other Wi-Fi CERTIFIED products - whether you are at home ,office , airports, coffee shops and other public areas equipped with a Wi-Fi access availability.Wi-Fi will be a major face behind hotspots , to a much greater extent.More than 400 airports and hotels in the US are targeted as Wi-Fi hotspots.
The Wi-Fi CERTIFIED logo is your only assurance that the product has met rigorous interoperability testing requirements to assure products from different vendors will work together. The Wi-Fi CERTIFIED logo means that it is a "safe" buy.
Wi-Fi certification comes from the Wi-Fi Alliance, a non profit international trade organisation that tests 802.11 based wireless equipment to make sure that it meets the Wi-Fi standard and works with all other manufacturer's Wi-Fi equipment on the market. The Wi-Fi Alliance (WELA) also has a Wi-Fi certification program for Wi-Fi products that meet interoperability standards. It is an international organisation devoted to certifying interoperability of 802.11 products and to promoting 802.11as the global wireless LAN std across all market segment.
IEEE 802.11 ARCHITECTURES
In IEEE's proposed standard for wireless LANs (IEEE 802.11), there are two different ways to configure a network: ad-hoc and infrastructure. In the ad-hoc network, computers are brought together to form a network "on the fly." As shown in Figure 1, there is no structure to the network; there are no fixed points; and usually every node is able to communicate with every other node. A good example of this is the aforementioned meeting where employees bring laptop computers together to communicate and share design or financial information. Although it seems that order would be difficult to maintain in this type of network, algorithms such as the spokesman election algorithm (SEA)  have been designed to "elect" one machine as the base station (master) of the network with the others being slaves. Another algorithm in ad-hoc network architectures uses a broadcast and flooding method to all other nodes to establish who's who
Use Search at http://topicideas.net/search.php wisely To Get Information About Project Topic and Seminar ideas with report/source code along pdf and ppt presenaion
Joined: Apr 2012
08-08-2012, 12:48 PM
WiFi.ppt (Size: 709.5 KB / Downloads: 63)
To develop a Medium Access Control (MAC) and Physical Layer (PHY) specification for wireless connectivity for fixed, portable and moving stations within a local area.
Frames types and subtypes
Three types of frames:
(ACK,RTS,CTS ,Power Save …)
(Beacon,Probe Request ,Probe Response,
Association request , Association response …)
(Data, Null Data, Data_CF_Ack , ….)
Infrastructure Model includes:
any wireless device
Access Point (AP)
connects BSS to DS
controls access by STA’s
Basic Service Set (BSS)
a region controlled by an AP
mobility is supported within a single BSS
Extended Service Set (ESS)
a set of BSS’s forming a virtual BSS
mobility is supported between BSS’s in an ESS
Distribution Service (DS)
connection between BSS’s
Two types of access to air
DCF (distributed coordination function )
means everybody can speak and try
to get air : 100% on the market
PCF (point coordination function)
means ONE point coordinator (BOSS)
who will allowed you to speak
(like in bluetooth)
WEP ( wired equivalent privacy) 64/128 bits
Using RC4 algorithm, almost permanent key, very week
security, able to crack by collecting statistic
Current security level for 99.9% products on the market.
TKIP (temporal key integrity protocol )
Used RC4 algorithm with with a 128-bit "temporal key"
but changes temporal keys every 10,000 packets and key dependes on address and sequence number.
Will be required to obtain WiFi certification from 09/01/03
AES (Advanced Encryption Standard )
New, much more stronger encryption, protect against hacker frames in insertion. Need hardware accelerator. Optional feature.
Joined: Apr 2012
02-10-2012, 01:41 PM
Wireless.ppt (Size: 402 KB / Downloads: 22)
Wireless Technology is an alternative to Wired Technology, which is commonly used, for connecting devices in wireless mode.
A Wi-Fi is an electronic devices, such as a personal computer, video game console, Smartphone, or digital audio player can connect to the internet via a wireless network access point.
An access point (or hotspot) has a range of about 20 meters (65 feet) indoors as few rooms and a greater range outdoors, as many square miles.
Wi-Fi access can provide at Organizations and businesses such as homes, offices, airports, hotels and restaurants often provide free-use hotspots to attract or assist clients.
Wi-Fi (Wireless Fidelity) is a generic term that refers to the IEEE 802.11 communications standard for Wireless Local Area Networks (WLANs).
IEEE 802.11 wireless LANs provides 1- or 2-Mbps transmission in the 2.4-GHz band using either frequency-hopping spread spectrum (FHSS) or direct-sequence spread spectrum (DSSS).
The 802.11 standard is defined through several specifications of WLANs such as,
How to connect Wi-Fi Network?
Basic concept is same as Walkie talkies.
A Wi-Fi hotspot is created by installing an access point to an internet connection.
An access point acts as a base station.
When Wi-Fi enabled device encounters a hotspot the device can then connect to that network wirelessly.
A single access point can support up to 30 users and can function within a range of 100 – 150 feet indoors and up to 300 feet outdoors.
Many access points can be connected to each other via Ethernet cables to create a single large network.
Wi-Fi Access Protocol
The 802.11 standards use a MAC layer known as CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance). In CSMA/CA a Wireless node that wants to transmit & performs the following sequence:
Listen on the desired channel.
If channel is idle (no active transmitters) it sends a packet.
If channel is busy then, the node waits until the transmission end then a contention period where minimum time a host must transmit before it can be sure that the no other host’s packet has collided with its transmission.
If the channel is still idle at the end of the contention period, then the node transmits its packet otherwise it repeats the process defined in step-3 above until it gets a free channel.
Wireless Protected Access (WPA)
This is a new standard from the Wi-Fi Alliance that uses the 40 or 104-bit WEP key, but it changes the key on each packet.
That changing key functionality is called the Temporal Key Integrity Protocol (TKIP).
Uses RC4,dynamic encryption with sessionkeys and 48 bit initialization vectors (IV).
Encryption provide Protection against man-in-the-middle attacks.
Wi-Fi is a universal wireless networking technology that utilizes radio frequencies to transfer data.
Wi-Fi allows for high speed Internet connections without the use of cables or wires.
It allows you to connect to the Internet from just about anywhere a coffee shop, a bed in a hotel room or a conference room at work without wires.
And the best thing of all, it's super fast almost 10 times faster than a regular dial-up connection.
Joined: Oct 2012
28-01-2013, 03:24 PM
to get information about the topic "WIRELESS FIDELITY" full report ppt and related topic refer the link bellow
seminar and presentationproject and implimentationsattachment.php?aid=26920