The Freedom of Wi-Fi - PowerPoint PPT Presentation

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The Freedom of Wi-Fi

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Title: The Freedom of Wi-Fi


1
MAHARANA PRATAP COLLEGE OF TECHNOLOGY, GWALIOR
Seminar On Wi-Fi Technology
Submitted to Submitted by Prof.
SACHIN SIR ALPANA MISHRA Dept.
EC. 3rd year 6th em
0903EC091005
2
Agenda
  • Introduction
  • Wi-Fi Technologies
  • Wi-Fi Architecture
  • Wi-Fi Network Elements
  • How a Wi-Fi Network Works
  • Wi-Fi Network Topologies
  • Wi-Fi Configurations
  • Applications of Wi-Fi
  • Wi-Fi Security
  • Advantages/ Disadvantages of Wi-Fi

3
Introduction
  • 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 Wireless Local Area Networks (WLANs).
  • Wi-Fi Network connect computers to each other, to
    the internet and to the wired network.

4
The Wi-Fi Technology
  • Wi-Fi Networks use Radio Technologies to
    transmit receive data at high speed
  • IEEE 802.11b
  • IEEE 802.11a
  • IEEE 802.11g

5
IEEE 802.11b
  • Appear in late 1999
  • Operates at 2.4GHz radio spectrum
  • 11 Mbps (theoretical speed) - within 30 m Range
  • 4-6 Mbps (actual speed)
  • 100 -150 feet range
  • Most popular, Least Expensive
  • Interference from mobile phones and Bluetooth
    devices which can reduce the transmission speed.

6
IEEE 802.11a
  • Introduced in 2001
  • Operates at 5 GHz (less popular)
  • 54 Mbps (theoretical speed)
  • 15-20 Mbps (Actual speed)
  • 50-75 feet range
  • More expensive
  • Not compatible with 802.11b

7
IEEE 802.11g
  • Introduced in 2003
  • Combine the feature of both standards (a,b)
  • 100-150 feet range
  • 54 Mbps Speed
  • 2.4 GHz radio frequencies
  • Compatible with b

8
802.11 Physical Layer
  • There are three sublayers in physical layer
  • Direct Sequence Spread Spectrum (DSSS)
  • Frequency Hoping Spread Spectrum (FHSS)
  • Diffused Infrared (DFIR) - Wide angle

9
Elements of a WI-FI Network
  • Access Point (AP) - The AP is a wireless LAN
    transceiver or base station that can connect
    one or many wireless devices simultaneously to
    the Internet.
  • Wi-Fi cards - They accept the wireless signal and
    relay information.They can be internal and
    external.(e.g PCMCIA Card for Laptop and PCI Card
    for Desktop PC)
  • Safeguards - Firewalls and anti-virus software
    protect networks from uninvited users and keep
    information secure.

10
How a Wi-Fi Network Works
  • 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.

11
Wi-Fi Network Topologies
  • AP-based topology (Infrastructure Mode)
  • Peer-to-peer topology (Ad-hoc Mode)
  • Point-to-multipoint bridge topology

12
AP-based topology
  • The client communicate through Access Point.
  • BSA-RF coverage provided by an AP.
  • ESA-It consists of 2 or more BSA.
  • ESA cell includes 10-15 overlap to allow roaming.

13
Peer-to-peer topology
  • AP is not required.
  • Client devices within a cell can communicate
    directly with each other.
  • It is useful for setting up of a wireless network
    quickly and easily.

14
Point-to-multipoint bridge topology
  • This is used to connect a LAN in one building to
    a LANs in other buildings even if the buildings
    are miles apart.These conditions receive a clear
    line of sight between buildings. The
    line-of-sight range varies based on the type of
    wireless bridge and antenna used as well as the
    environmental conditions.

15
Wi-Fi Configurations
16
Wi-Fi Applications
  • Home
  • Small Businesses or SOHO
  • Large Corporations Campuses
  • Health Care
  • Wireless ISP (WISP)
  • Travellers

17
Wi-Fi Security Threats
  • Wireless technology doesnt remove any old
    security issues, but introduces new ones
  • Eavesdropping
  • Man-in-the-middle attacks
  • Denial of Service

18
Wi-Fi Security
  • The requirements for Wi-Fi network security can
    be broken down into two primary components
  • Authentication
  • User Authentication
  • Server Authentication
  • Privacy

19
Authentication
  • Keeping unauthorized users off the network
  • User Authentication
  • 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

20
Advantages
  • Mobility
  • Ease of Installation
  • Flexibility
  • Cost
  • Reliability
  • Security
  • Use unlicensed part of the radio spectrum
  • Roaming
  • Speed

21
Limitations
  • Interference
  • Degradation in performance
  • High power consumption
  • Limited range

22
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