Upload
rahul-kumar
View
213
Download
0
Embed Size (px)
Citation preview
8/8/2019 Presentation on W-fi 0051563107
1/26
8/8/2019 Presentation on W-fi 0051563107
2/26
A Networking Technology that allowsthe connection of devices in wirelessmode.
Also called as Wireless LAN.
Called LAN because the range targetswithin
Office Campus
Building Just a House
Store
8/8/2019 Presentation on W-fi 0051563107
3/26
Basic concept is same as Walkie Talkies.
Wi-Fi Networks, mostly uses radio &
infrared frequencies (RF) technology to
transmit & receive data at high speed.
A Wi-Fi hotspot is created by installing an
access point to an internet connection.
An access point acts as a base station.
8/8/2019 Presentation on W-fi 0051563107
4/26
8/8/2019 Presentation on W-fi 0051563107
5/26
Wi-Fi is a short form of Wireless Fidelity.
It is a generic term that refers to the IEEE
802.11 communications standards for
Wireless Local Area Network (WLANs).
Inter operability standard for Wireless
Fidelity using IEEE802.11b/802.11a/802.11g standard.
8/8/2019 Presentation on W-fi 0051563107
6/26
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.
8/8/2019 Presentation on W-fi 0051563107
7/26
Appear in late 1999 Operates at 2.4GHz radio spectrum
11 Mbps (theoretical speed) - within 30 m
Range
4-6 Mbps (actual speed)
100 -150 feet range
Most popular, Least Expensive
Interference from mobile phones andBluetooth devices which can reduce the
transmission speed.
8/8/2019 Presentation on W-fi 0051563107
8/26
Introduced in 2001 Operates at 5 GHz (less popular)
54 Mbps (theoretical speed)
15-20 Mbps (Actual speed) 50-75 feet range
More expensive
Not compatible with 802.11b
8/8/2019 Presentation on W-fi 0051563107
9/26
Extension of 802.11b, with the samedisadvantages (security and interference)
Has a shorter range than 802.11b
Is backwards compatible with 802.11b so itallows or a smooth transition from 11b to 11g
Flexible because multiple channels can becombined for faster throughput, but limitedto one access point
Runs at 54 Mbps, but realistically about 20-25Mbps and about 14 Mbps when b associated
Uses frequency division multiplexingtechnology
8/8/2019 Presentation on W-fi 0051563107
10/26
Wireless
Standards
802.11b 802.11g 802.11a
Frequency Range 2.4 GHz 2.4 GHz 5GHz
Max Speed 11 MBPS 54 MBPS 54 MBPS
Max Encryption 128 bit WEP 128 bit WEP 152 bit WEP
128 bit WEP
Distance Covered 300 ft 300 ft 100 ft
Potential User Entry level and
home networks
Larger networks,
small business
Large business
concerned with
security
8/8/2019 Presentation on W-fi 0051563107
11/26
11B: 2.4 GHz, CCK modulationRates from 1 to 11Mbps, on market from 1999.
11A: 5.0 GHz, OFDM modulation
Rates from 6 to 56Mbps, on market from 2002.
11G: 2.4 GHz, CCK+OFDM modulation
Rates from 6 to 56Mbps, on market from 2003
and most popular today!!
2.4GHz & 5.0GHz are public available frequencies.
8/8/2019 Presentation on W-fi 0051563107
12/26
Access Point : The AP is a wireless LAN transcieveror base station that connect one or many wirelessdevices simultaneously to the internet.
Wi-Fi Cards :They accept the wireless signal and
relay information. They can be internal and external.
(e.g. PCMCIA card for Laptop and PCI card forDesktop PC)
Safeguards : Firewalls and anti-virus softwareprotect networks from uninvited users and keepinformation secure
8/8/2019 Presentation on W-fi 0051563107
13/26
AP-based topology (Infrastructure
Mode)
Peer-to-peer topology (Ad-hoc
Mode)
Point-to-multipoint bridge topology
8/8/2019 Presentation on W-fi 0051563107
14/26
The client communicate through Access Point.
BSA-RF coverage provided by an AP.
ESA-It consists of 2 or more BSA.
ESA cell includes 10-15% overlap to allowroaming.
8/8/2019 Presentation on W-fi 0051563107
15/26
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 andeasily.
8/8/2019 Presentation on W-fi 0051563107
16/26
This is used to connect a LAN in one building to aLANs 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.
8/8/2019 Presentation on W-fi 0051563107
17/26
Security
y Wi-Fi was not designed with robust
security in mind
Interference
y operates in unlicensed 2.4 GHz spectrum
y competes with other products e.g.
microwave ovens!y Speed Slower than cable
Scarcity of hotspots
8/8/2019 Presentation on W-fi 0051563107
18/26
8/8/2019 Presentation on W-fi 0051563107
19/26
Performance decreases as distance increases
Indoor 40-300 feet
Outdoor 100 to 1000 feet
Indoor 100-300 feet
Outdoor 400 1500 feet
- doors, walls, furniture, ceiling
253 maximum number of client per AP, but15-20recommended
8/8/2019 Presentation on W-fi 0051563107
20/26
The requirements for Wi-Fi network
security can be broken down into two
primary components:
Authentication
User Authentication
Server Authentication
Privacy
8/8/2019 Presentation on W-fi 0051563107
21/26
Keeping unauthorized users off thenetwork
User Authentication
Authentication Server is used Username and password
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
8/8/2019 Presentation on W-fi 0051563107
22/26
Server Authentication
Digital Certificate is used
Validation of digital certificate occurs
automatically within client software
8/8/2019 Presentation on W-fi 0051563107
23/26
Mobility
Ease of Installation
Flexibility
Cost
Reliability
Security
Use unlicensed part of the radio spectrum Speed
8/8/2019 Presentation on W-fi 0051563107
24/26
Interference
Degradation in performance
High power consumption Limited range
8/8/2019 Presentation on W-fi 0051563107
25/26
Home
Small Businesses
Large Corporation & Campus Travelers
Wireless ISP (WISP)
8/8/2019 Presentation on W-fi 0051563107
26/26