Wireless Networking
Concept
Wireless networking means
connection without wire and cable is not use as medium for connection but RF
(Radio Frequency) waves are use for connection. By default RF waves cannot
carry bits or data. We have to use Shift Keying method to carry data or bits using
RF waves. Shift Keying method means to disturb the waves or to change the characteristics
of RF waves.
Characteristics of RF
waves are:-
1. FM (Frequency
Modulation)
It means number of waves
generate per second. It is absolute measurement. Its unit is Hertz. Maximum 2.4
GHz is allowed for general purpose and 5 GHz for special purpose like Defence.
2. Amplitude
It means height of waves.
It require lot of power. It is measure in Watt. It is also absolute
measurement.
3. Phase
It means difference between
two waves. It is relative measurement and its unit is Degree.
There are 3 organizations
which can set the standards for wireless networking and these organizations can
work in hierarchical manner:-
1. ITU-R (International
Telecommunication Union - Radiation)
It can set the rules and
boundaries for indoor and outdoor. For eg:- 2.4 GHZ
2. IEEE (Institute of
Electrical and Electronic Engineers)
It work within boundary of
ITU-R and set the wireless networking standards. IEEE 802.11x (802.11g) is
wireless netwoking standard.
3. Wi-Fi Alliance
(Wireless Fidelity)
It is certification body
which can certify the wireless networking devices.
Wireless Networking
Devices:-
1. Wireless NIC or Data
Card
It is use to receive
waves, it is wireless transceiver.
2. Access Point
It is wireless
transmitter, it can generate the RF waves.
3. IR (Intentional
Radiator)
It is a device which can
generate waves or radiation intentionally. Eg:- Microwave
4. EIRP (Equivalent
Isotropical Radiation Power)
It means anything which
can generate waves or energy in all the directions equally in 360 degrees. Eg:-
Sun or Solar Energy
5. Antenna
It is use to send and
receive waves between the different wireless devices.
Types of antenna:-
1. Omni-directional
antenna
It can send waves in all
the directions but it can cover very small area. Eg:- Access point antenna.
2. Semi-directional
antenna
It can send waves in one
direction only but it can cover very large area like a street lamp. Eg:- Yagi antenna use on towers.
3. Hi-directional antenna
It can cover long
distances. Eg:- Dish antenna.
NOTE: WEP, WPA, TKIP etc
are the protocols use for wireless security.
Function of Access Point:-
1. Access Point (Wireless hub)
2. DHCP server
3. Repeater
4. Bridge (It can connect another Access Point)
5. NAT
6. Routing
