General trade association called WI-FI alliance. Thus

General Introduction

Wi-Fi is a wireless
technology that uses the radio frequency of range 2.4 GHz HUF and 5 GHz SHF to
transmit data through air. Wi-Fi is stand for wireless Fidelity. It is a
generic term that refers to IEEE 802.11 standard which is used in term as early
as August 2000 coined by brand consulting firm called Interbrand corporation.
All the wifi technology and products are promoted and certified by a trade
association called WI-FI alliance. Thus wifi alliance defines the wifi as a
Wireless Local Area Network. All those products which successfully complete all
the tests of wifi interoperability are only trademarked wifi certified by wifi
alliance. It is a short-range wireless transmission technology which
interconnects Wi-Fi devices like personal computers, hand-held devices and
other terminals, so it is more prone to the intruder’s attacks. To provide
security to wifi many protocols have been developed, but still intruders are
able to attack this wireless network. Wi-Fi  is also known as “802.11a” “802.11b” “802.11g”
and “802.11n”. Recently in August 2013 “802.11ac” has also been launched. (Sharma, May 2014)

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Fig 1. Wireless Local Area Network Connected to the
Internet.

Current
scenario

The
wifi technology have made a huge impact on the market. This is only possible to
incorporate the wireless LAN technology in Laptops, PCs, Printers, Cellphones,
and VoIP Phones, MP3 Players, in our homes, in offices and even in public area
only with the introduction of the IEEE 802.11 Standards. (Banerji &
Chowdhury, 4/2013)

As the popularity of
Wi-Fi emerged with the use of 802.11ac supported equipment’s, the 802.11ac access
point become cheaper and cheaper by the distributer and suppliers. Therefore
the graph of adoption rate of 802.11ac become higher and higher. Many enterprises
introduce for cloud solutions for Wi-Fi management and services to ensure the
maximum providence of services to companies’ technology When it is certified by
Passpoint and it is ready to enter the smart phone market, Wi-Fi takes another
shape as Hotspot 2.0 which brings a revolution in an easy, compact and portable
pocket Wi-Fi. It finds another way to enterprise providing Wi-Fi access. (Song &
Biju, WIFI, November/2014)

 

Background

With The development of Technology, in
present days wireless solutions are getting popular in Networking. In which
wireless broadband access with high speed, large coverage and mobility is
today’s people’s demand. So to fulfill this requirement a new technology is
invented with the introduction of the IEEE 802.11 Standards. (Song &
Biju, General Introduction, November/2014)

WI-FI NETWORK TOPOLOGIES

Topologies
mean how the nodes are connected in a network. In Wi-Fi network also we have
different topologies which shows how network if formed. These are as follows.

Independent Basic Service set (IBSS) –
IBSS configuration is also known as independent configuration or ad hoc
network. It’s a peer-to-peer network in which no single node is required to act
as server. The nodes or wireless stations can directly communicate with each
other on ad hoc basis by using an access point. But it has limited coverage
area.

Basic Service Set (BSS)
– BSS
consist of at least one access point connected to the wired network
infrastructure and set of wireless end stations. BSS configurations rely on an
access point that acts as the logic server for a single WLAN cell or channel.
Communication between node A and node B actually flows from node A to access
point, then from access point to node B.

Extended Service Set (ESS) – ESS
consist of a services of overlapping BSS connected together by means of a
distributed system (DS). DS could be any type of network. Mobile nodes can roam
between access points to and like this seamless camps wide coverage is
possible.

Wi-Fi
STANDARDS

 Wi-Fi have IEEE 802.11 Standard. This is
further subdivided as below:

IEEE 802.11a – This standard has no work
right now.

IEEE 802.11b – Its
frequency range is 2.4 GHz, and maximum bandwidth is 11Mbps.

IEEE 802.11g – Its
frequency is 2.4 GHz and throughput is more than IEEE 802.11a because in this
the channel size is increased. Its maximum bandwidth is 54 mbps.

IEEE 802.11n – its
frequency range is from 2.4 GHz to 5 GHz and maximum bandwidth is 300 Mbps.

IEEE
802.11ac – This is the most recent standard launched in August 2013. Its
frequency range is 5 GHz or more and bandwidth is 7 Gbps.