The document discusses wireless fidelity (WiFi) and IEEE 802.11 standards. It describes the setup required for WiFi including access points and wireless cards. It then covers how WiFi works using radio waves, the network topologies of AP-based and peer-to-peer, and common WiFi security threats like eavesdropping and denial of service attacks. It also lists advantages, disadvantages, and applications of WiFi networks.

1. Wireless Fidelity

2. AGENDA
 Introduction
 What is IEEE 802.11
 Setup required for WiFi
 Working of WiFi
 WiFi Network Topologies
 WiFi Security Threats
 WiFi Security
 Advantages
 Disadvantages
 Comparison B/w Wired & Wireless Network
 Application of WiFi

3. INTRODUCTION
 Wireless Technology is an alternative to Wired
Technology, which is commonly used, for connecting devices
in wireless mode.
 WiFi is a wireless technology that uses radio frequency to
transmit data through the air.
 WiFi is a generic term that refers to the IEEE 802.11
communications standard for Wireless Local Area Networks
(WLANs).
 WiFi Network connect computers to each other, to the
internet and to the wired network.
 It offers peak data speeds of up to 11 Mbps.

4. What is IEEE 802.11
IEEE 802.11 is a set of standards carrying out Wireless Local
Area Network (WLAN) computer communication in the 2.4 to
5 GHz frequency bands. They are created and maintained by
the IEEE (Institute of Electrical & Electronics Engineers)
Standards Committee.
IEEE 802.11b
IEEE 802.11a
IEEE 802.11g

5. IEEE 802.11b
 Appeared in late 1999
 Operates at 2.4GHz radio spectrum
 4-6 Mbps (actual speed) can go up to 11 Mbps within
the range of 30 m
 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 radio spectrum (less popular)
 15-20 Mbps (Actual speed) can go up to 54 Mbps as
the range reduces
 50-75 feet range
 More expensive
 Not compatible with 802.11b

7. IEEE 802.11g
 Introduced in 2003
 Operates at 2.4 GHz radio spectrum
 54 Mbps (Actual speed)
 100-150 feet range
 Combines the features of both Standards i.e.
IEEE 802.11b & IEEE 802.11a
 Compatible with 802.11b

8. Setup Required for WiFi
 ACCESS POINT
 Consists of a Radio Transmitter and receiver
as well as an interface to a wired network or directly to
the internet
 Serves as a base station and a bridge between
the wireless network and a larger Ethernet network or
the internet.

9.  WIRELESS CARDS
 Network card which connects to a radio-based
computer network, unlike a regular network interface
controller (NIC) which connects to a wire-based network
such as Ethernet.
 They accept the wireless signal and relay
information. They can be internal and external

10. Working of WiFi
 Basic concept is same as Walkie talkies
 A WiFi hotspot is created by installing an access point to an internet
connection
 An access point acts as a base station .
 When WiFi enabled device encounters a hotspot the device can then
connect to that network wirelessly.
 A Wireless Network uses Radio Waves, just like Cell phone, Radio do.

11.  A computer’s Wireless Adapter translates data into Radio signals and
transmit it using Antenna.
 A wireless router receives the signals and Decodes it. The Router sends
the Information to the Internet.
 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.

12. WiFi Network Topologies
 AP-based topology (Infrastructure Mode)
 Peer-to-peer topology (Ad-hoc Mode)
 Point-to-multipoint bridge topology

13. AP-based topology
 The client communicates through Access Point.
 Basic Service Area-Radio Frequency coverage
provided by an AP.
 Extended Service Area - It consists of 2 or more BSA.
 ESA cell includes 10-15% overlap to allow roaming.

14. Peer-to-peer topology
 Access Point is not Required.
 Client Devices within a cell can communicate directly
with each other.
 It is useful for setting up of wireless network quickly
and easily.

15. Point-to-Multipoint Bridge
topology
 Used to connect LAN’s b/w two or more buildings
even miles apart.
 These conditions receive a clear line of sight b/w
buildings.
 The line of Sight range varies based on the type of
wireless bridge and antenna used as well as the
environment conditions.

16. WiFi SECURITY Threats
 Wireless technology doesn’t remove any
old security issues, but introduces new ones
Eavesdropping
Man-in-the-middle attacks
Denial of Service

17. Eavesdropping
 Easy to perform, almost impossible to detect
 By default, everything is transmitted in clear text
 Usernames, passwords, content ...
 No security offered by the transmission medium
 Different tools available on the internet
 Network sniffers, protocol analysers . . .
 Password collectors
 With the right equipment, it’s possible to eavesdrop
traffic from few kilometers away

18. Man In The Middle Attack
 Attacker spoofes a disassociate
message from the victim
 The victim starts to look for a
new access point, and the
attacker advertises his own AP
on a different channel, using
the real AP’s MAC address
 The attacker connects to the
real AP using victim’s MAC
address

19. Denial of Service
 Attack on transmission frequecy used
 Frequency jamming
 Not very technical, but works
 Attack on MAC layer
 Spoofed deauthentication / disassociation messages
 can target one specific user
 Attacks on higher layer protocol (TCP/IP protocol)
 SYN Flooding

20. WiFi SECURITY
The requirements for WiFi network security consists of an
primary component i.e. :
 Authentication
 User Authentication
 Server Authentication

21. Authentication
Keeping unauthorized users off the network
 User Authentication
 Authentication Server is used
 Done using Username and password of the User
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

22.  Server Authentication
 Digital Certificate is used
 Validation of digital certificate occurs
automatically within client software

23. Advantages
 Flexible Working:
Access the Internet, do File Transfers, even Print from anywhere within 100
meters of the WiFi Access Point.
 Reduce Cable Clutter:
Reduce the clutter of wires and cables behind your Desktop/ Notebook
 Reduce Setup Cost:
Save the cost of cabling and the cost on Network sockets
 Avoid Deterioration with Time:
Network Cables and Sockets tend to deteriorate over time, while WiFi does
not have this disadvantage
 Eliminate Re-configuring Computers:
Can Access WiFi at two different locations under the same company’s
network without having to re-configure their Internet settings each time.

24. Disadvantages
 Password and Security:
It is important to secure your WiFi connection at home or the office. Otherwise,
anyone with a WiFi enabled computer can access your data and Internet connection!
Password-protecting your WiFi connection is an easy process and once you set up all
your Computers and devices to access your WiFi network, you do not need to type in
passwords each time thereafter.
 Signal Strength Sensitivity:
WiFi Networks are sensitive to signal strength. To ensure good connectivity,
you must ensure that all computers and gadgets receive adequate signal strength
 Effect of Climatic Conditions:
WiFi signals are likely to be adversely affected by climatic conditions such as
thunderstorms.
 Increased number of Network Devices:
You are increasing the number of devices on your Network, by incorporating a
WiFi Access point. Also, you will need a power socket to plug in and power the WiFi
Access Point.

25. Comparison B/w Wired &
Wireless Network
Features Wired Home Network Wireless Home
networks
The networking of the wired The networking of the
Networking home networks are more wireless networking is good
faster as compared to other and better for the future
types of wireless networking resources but it is not faster
devices because they are as the wired home
able to provide the speed of networking devices. Wifi is
more then 1000 Mbps the common types of
wireless home network that
can provide the reliable
working
Cost Comparison We need many expenses to As compared to other wired
configure or setup the wired devices it is easy to setup the
home network. Because we wireless networking devices
need large money to spread at the very low and at the
the network of coaxial reliable cost
cables.

26. Comparison B/w Wired &
Wireless Network . . . Contd…
Features Wired Home Network Wireless Home networks
Advantages More reliable You can Access internet
Faster internet from any place through hot
Transfer of data at a very pots
faster speed No hassles of cables
No need any kind of wiring
for installation
Cons It can not provide mobile Not very much reliable
network Only best for mobile
Difficult to lay down the devices such as Laptops
cables and it looks very Not faster as compared to
messy when install outside wired devices

27. Application of WiFi
 Sharing of Files:
Sharing and Exchanging of Data can take place with nearby Computers in the
Network.
 Accessing the Internet:
Using the WiFi, Internet can be made available to the Computers connected to
the Network.
 Stream Audio to Wireless Speakers:
One of the useful application of WiFi is that using it one can Stream audio to
audio devices present in the Network Area that are compatible to it.
 Device Sharing:
Similar to Wired Network WiFi provides the feature to access the Devices being
shared within the Network. Like one can command the Printer attached to any
System in the network and get their documents print.