Wi-Fi is a wireless technology that allows devices to connect to the internet and each other without being physically connected with cables. It uses radio waves to enable wireless network access across multiple devices. The Wi-Fi Alliance tests and certifies products for interoperability and compliance with IEEE 802.11 wireless standards. Wi-Fi provides the benefit of mobility and flexibility without cables but has disadvantages such as slower speeds and potential security risks compared to wired connections.

1. Wi-Fi

2. • Introduction
• Needs of Wi-Fi
• Purpose
• History
• Technology
• Topology
• System Architecture
• Configurations
• Applications
• Advantages & Disadvantages

3. • Wireless Technology is an alternative of Wired technology, which is
commonly used, for connecting devices in wireless mode.
• Wi-Fi 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.
• Wi-Fi works on Physical and Data Link layer.

4. • The term Wi-Fi suggests Wireless fidelity, resembling the long-
established audio-equipment classification term high fidelity (in use since
1930s) or Hi-Fi (used since 1950)
• Phil Belanger who is the founding member of the Wi-Fi Alliance states
that term Wi-Fi was never supposed to mean anything to all.
• The “yin-yang” logo indicates the certification of a product for
interoperability.
Wi-Fi technology

5. • One can move around freely within the area of the network with their
laptops, other hand-held devices connected to the internet.
• Users can also be able to share file and other resources with other
devices that are connected to the network without having to be cabled
to a port.
• Not having to lay lots of cables and put them through walls.
• If a person has a business such as a café, having a wireless network
that is accessible to customers can bring extra business.
• Wireless LANs can sometimes handle a larger amount of users
because they are not limited by a specific number of connection ports.
• Instant transfer of information to social media is made much more
easier.

6. • The purpose of Wi-Fi is to hide complexity by enabling wireless
access to applications and data, media and streams.
• The main aim of Wi-Fi are :
- Make access to information easier.
- Ensure compatibility and co-existence of devices.
- Eliminate complex cabling.
- Eliminate switches, adapters, plugs, pins and connectors.
Freedom from wires..!!

7. Wi-Fi Alliance
• Wi-Fi technology builds on IEEE 802.11 standards. The
IEEE develops and publishes these standards, but does
not test equipment for compliance with them. The non-
profit Wi-Fi Alliance formed in 1999 to fill this void.
• The Wi-Fi Alliance, a global association of companies.
• As of 2009 the Wi-Fi Alliance consisted of more than 300
companies from around the world.
• Manufacturers with membership in the Wi-Fi Alliance,
whose products pass the certification process, gain the
right to mark those products with the Wi-Fi logo.

8.  The technology used in Wi-Fi is easiest to understand in terms of
“radio” as it provides wireless access to applications and data across
using radio waves.
 In Wi-Fi radios, the signal strength is much more, so they can handle
much higher data rates.
 There are three versions of Wi-Fi radios currently available- the ones
that work with,
 802.11b
 802.11a
 802.11g

9. • Comparison between 3 standards of Wi-Fi are mentioned below

10. • AP Based Topology
• Peer to peer Topology
• Point to multi-point bridge Topology

11.  BSS- Basic service set(Wireless cell) ,it is the basic building block
which consists of wireless stations(stationary & mobile) and central
base station(Access point-AP)
 The client communicate through Access Point
 ESS-Extended service set, connect 2 or more BSS. In this case the
BSS are connected through a distributed system(wired LAN)
 ESS cell includes 10-15% overlap to allow roaming

12.  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.

13.  This is used to connect a LAN in one building to 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.

14. • Infrastructure based:
 When BSS are connected
 Devices within the same BSS can communicate with each other without the
help of AP, but communication between two different BSS usually occur via
two Aps
• Ad-hoc based:
 BSS without AP(already discussed in Peer-peer topology)

15.  Wi-Fi is composed of three main sectors:
 Home (individual residences and apartment buildings)
 Public (Round about 70,000 “hotspots” through out the world)
 Enterprise (corporations, universities, office parks)

16. • Building-to-building connections
• Video, audio conferencing/streaming video,
and audio
• Large file transfers.
• Faster Web access and browsing.

17. • Freedom – You can work from any location that you can get a
signal.
• Setup Cost – No cabling required.
• Flexibility – Quick and easy to setup in temp or permanent space.
• Scalable – Can be expanded with growth.
• Mobile Access – Can access the network on the move.

18. • Speed – Slower than cable.
• Range – Affected by various medium.
• Travels best through open space.
• Reduced by walls, glass, water, etc
• Security – Greater exposure to risks.
• Unauthorized access.
• Compromising data.
• Denial of service.