Wi-Fi Presented By: N. Rakesh Kumar (07D01A0591)

What is Wi-Fi?  Wi-Fi stands for Wireless Fidelity and is used to define any of the wireless technology in the IEEE specification - including (but not necessarily limited to) the wireless protocols a, b, and g.  Wi-Fi is a wireless technology that uses radio frequency to transmit data through the air.

Brief History  IEEE (Institute of Electrical and Electronics Engineers) established the Group in Specifications for standard ratified in  Initial speeds were 1 and 2 Mbps.  IEEE modified the standard in 1999 to include a and b.  g was added in  b equipment first available, then a, followed by g.

What can you do with it? Quick/easy temp network access. Staff access to Corporate network. Patron internet access (hotspot). Interconnecting two networks

What is the goal of standard To develop a Medium Access Control (MAC) and Physical Layer (PHY) specification for wireless connectivity for fixed, portable and moving stations within a local area. Infrastructure Model: i. Licence. ii. Context With OSI Layers.

Why do we need 11A/11B/11G ? 11B: 2.4 GHz, CCK modulation Rates from 1 to 11Mbps, on market from A: 5.0 GHz, OFDM modulation Rates from 6 to 56 Mbps, on market from G: 2.4 GHz, CCK+OFDM modulation Rates from 6 to 56 Mbps, on market from 2003 and … most popular today !!! Advantages of 2.4 GHz PHY Low frequency, better wall penetration, less sensitive to multipath, 3 not-overlapped channels. Advantages of 5.0 GHz PHY Range: Less devices on the market, 8 non overlapped channels. Range: Almost the same

Type of access to air DCF (distributed coordination function ) (point coordination function) means everybody can speak and try to get air : 100% on the market PCF means ONE point coordinator (BOSS) who will allowed you to speak (like in Bluetooth).

Why Wi-Fi? Setup Cost : Reduced cabling required. Flexibility: Quick and easy to setup in temp or permanent space. Scaleable: Can be expanded with growth Freedom: You can work from any location that you can get a signal. Lower total cost of ownership: Because of affordability and low install cost. Additionally Mobile Users: Can access the Corporate network from any public hotspot.

Security WEP ( wired equivalent privacy) 64/128 bits Using RC4 algorithm, almost permanent key, very weeK security. TKIP (temporal key integrity protocol ) Used RC4 algorithm with a 128-bit "temporal key”, but changes temporal keys every 10,000 packets and key depends on address and sequence number. AES (Advanced Encryption Standard ) New, much more stronger encryption, protect against hacker frames in insertion. Need hardware accelerator.

Range and Performance Performance decreases as distance increases i a indoor feet outdoor feet ii b indoor feet outdoor feet Interference: doors, walls, furniture, ceiling 253 maximum number of client per AP, but recommended

Wireless network design Any wireless network can be thought of as a combination of one or more of these types of connections: Point-to-Point Point-to-Multipoint Multipoint-to-Multipoint

Radio Modes Wi-Fi cards can be operated in one of these modes: Master (Access Point) Managed (also known as client or station) Ad-hoc

Advantages & Challenges Operational advantages: Wi-Fi allows local area networks (LANs) to be deployed without wires for client devices. Reducing the costs of network deployment and expansion. Reach: Wi-Fi networks have limited range. Wi-Fi performance decreases roughly quadratically as distance increases at constant radiation levels. Mobility: Mobile use of Wi-Fi over wider ranges is limited to move & use.

Data security risks: The most common wireless encryption standard, Wired Equivalent Privacy or WEP, has been shown to be easily breakable even when correctly configured. Population: Many 2.4 GHz b and g access points default to the same channel on initial startup, contributing to congestion on certain channels.

Disadvantages Security - Greater exposure to risks i. Access ii. Compromising Data Speed - Slower than cable Range - Affected by various medium i. Travels best through open space ii. Reduced by walls, glass, water, etc

Uses Internet access Airport Wi-Fi City-wide Wi-Fi Campus-wide Wi-Fi Direct computer-to-computer communications

THANK TOU. THANK TOU.