Wi-Fi

CONTENTS

Introduction History What is Wi-Fi How Wi-Fi works Wi-Fi Standards Topologies Security Advantages Disadvantages Application Conclusion Future

INTRODUCTION

• Wi-Fi is the wireless way to handle networking.

• Wireless Technology is an alternative to Wired Technology , which is commonly used, for connecting devices in wireless mode .

• Wi-Fi (Wireless Fidelity) is a generic term that refers to the IEEE 802.11 communications standard for WLANs.

HISTORY OF Wi-Fi

• The precursor to Wi-Fi was invented in 1991 by NCR Corporation with AT&T Corporation in Nieuwegein, the Netherland.

• The first wireless products were brought on the market under the name WaveLAN with speeds of 1Mbit/s to 2Mbit/s.

• Vic Hayes has been named as father of “Wi-Fi”.

HISTORY OF Wi-Fi

• In 1992 and 1996, Australian organization CSIRO obtained patents for a method later used in Wi-Fi.

• In April 2009, 14 tech companies agreed to pay CSIRO $250 million for infringements on CSIRO patents

• As of 2010, the Wi-Fi Alliance consisted of more than 375 companies from around the world.

How Wi-Fi works

Wi-Fi Standards

802.11aRuns in the 5 GHz rangeUses OFDM technologyHas 12 channels, 8 non-overlapping, and

supports rates up to 54MbpsFlexible because multiple channels can be

combined for faster throughput and more access points can be collocated

Wi-Fi Standards

802.11b• Runs in the 2.4 GHz frequency range• Use DSSS technology• Has 11 channels, with 3 non-overlapping and supports up to 11 Mbps

Upcoming standards

• 802.11g : Backwards compatible with 802.11b with the same disadvantage

• 802.11b+ : Backwards compatible with 802.11b supports rates up to 22 Mbps

• 802.11i : Provides more security by advance encryption technology.

• 802.11e : More multimedia friendly for viewing streaming videos.

Wi-Fi Standards

• IEEE 802.11n: Introduced in 2003 100-150 feet range 140 Mbps Speed 54Mbps (actual speed) 2.4 GHz Outdoor ranges 2000 feet

Range & performance

• 802.11a -Indoor 40-300 feet -outdoor 100 to 1000 feet• 802.11b -Indoor 100-300 feet -outdoor 400 to 1500 feet

Wi-Fi Topologies

AP-based topology • Peer-to-peer topology

• Point-to-multipoint bridge topology

About radio frequency

• There is no wire connection between sender & receiver.

• Two types RF is used-• 1-Direct sequence spread spectrum radio

technology.• 2-Orthogonal frequency division multiplexing

Typical community Wi-Fi Constituents

• Sector antenna• Other components• Customer premises equipment• High gain parabolic grid antennas

A sticker indicating to the public that a location is within range of a Wi-Fi

network. A dot with curved lines radiating from it is a common symbol for Wi-Fi,

representing a point transmitting a signal.

CITY-WIDE WI-FI

In 2004, Mysore became India's first Wi-Fi-enabled city and second in the world after Jerusalem.In 2005, Sunnyvale, California, became the first city in the United States($44)

An embedded RouterBoardWireless routers integrate a Wireless Access Point.

A wireless router allows wired and wireless Ethernet LAN devices to connect to a single WAN device such as a cable modem or a DSL modem.

USB wireless adapter

Wireless adaptor allow devices to connect to a wireless network. These adapters connect to devices using

various external or internal interconnects such as PCI, miniPCI, USB, Express Card, Cardbus and PC card.

As of 2010, most newer laptop computers come equipped with built in internal adapters.

 

Wi-Fi in Your LifeWi-Fi uses radio waves to create reliable high-

speed connections between computers, printers, gaming devices, cameras phones and home

entertainment systems. You can use Wi-Fi in your home, at work or on-the-go at hotspots

worldwide.

Why Wi-Fi

• Setup cost –reduced cabling required

• Flexibility – quick and easy to setup

• Scalability – can be expanded with growth

• Freedom – you can work from any location

Operating modes

• Infrastructure Mode

• AD HOC Mode

Wi-Fi Threats

• Eavesdropping(sniffers, protocol analyzers Password collectors)

• MITM Attack(change AP)

• Denial of services(freq.)

Wi-Fi Security

• Authentication User Server Privacy • Authentication: Authentication Keeping unauthorized users off the

network User Authentication Server is used Username and password Risk: Data (username & password) send before secure channel established Prone to passive eavesdropping by attacker Solution Establishing a encrypted channel before sending username and password .

SECURITY

• Data Security/Encryption

• WEP-Shared key&ICV

• SSID

• WPA(TKIP&PSK)

Capabilities and uses

• Online video conferencing with greater clarity• Telephony ,using VoIP• Broadband in the true sense• Easier reach into far-flung rural areas• Ability to add more nodes as and when

required

Advantages

• Wi-Fi can make access publically available at Wi-Fi hotspots.

• Does not require regulatory approval for individual.• Wi-Fi network can support roaming.• Wi-Fi allows local area network to deployed

without wires for client devices.• High data transmission rate • High reliable• Good network

Advantages

• It’s also suitable for high bandwidth• Less maintenance• Mobile• Relatively inexpensive• Easy to set up a network• User-friendly software• Security features• Global set of standards.

Disadvantage of 802.11a

As this standard does not support frequency hoping in response to interference it retransmits or wait for the higher level TCP/IP protocol to sort out signal from noise.

This works well for data transmission but can result in voice transmission.

Disadvantage of 802.11b

• It is prone to interference from other devices (microwave ovens, cordless phones, etc) and also has security disadvantages

• It limits to the number of access points in range of each other

DISADVANTAGE OF Wi-Fi

Limited range Interference

degradation in performance

High power consumption

APPLICATION OF Wi-Fi

• Home• Small Businesses • Large Corporations • Campuses • Health Care• Educational • Institutions • Banks

FUTURE

• Wi-Fi enables wireless voice-applications (VoWLAN or WVOIP). Over the years, Wi-Fi implementations have moved toward "thin" access points, with more of the network intelligence housed in a centralized network appliance, relegating individual access points to the role of "dumb" transceivers. Outdoor applications may utilize mesh topologies.