Wi-Fi TechnologyWi-Fi Technology

AgendaAgenda• IntroductionIntroduction• Wi-Fi TechnologiesWi-Fi Technologies• Wi-Fi Network ElementsWi-Fi Network Elements• How a Wi-Fi Network WorksHow a Wi-Fi Network Works• Wi-Fi Network TopologiesWi-Fi Network Topologies• Wi-Fi ConfigurationsWi-Fi Configurations• Applications of Wi-FiApplications of Wi-Fi• Wi-Fi SecurityWi-Fi Security• Advantages/ Disadvantages of Wi-FiAdvantages/ Disadvantages of Wi-Fi

IntroductionIntroduction• Wireless Technology is an alternative to Wired Wireless Technology is an alternative to Wired

Technology, which is commonly used, for Technology, which is commonly used, for connecting devices in wireless mode.connecting devices in wireless mode.

• Wi-Fi (Wireless Fidelity) is a generic term that Wi-Fi (Wireless Fidelity) is a generic term that refers to the IEEE 802.11 communications refers to the IEEE 802.11 communications standard for Wireless Local Area Networks standard for Wireless Local Area Networks (WLANs).(WLANs).

• Wi-Fi Network connect computers to each other, Wi-Fi Network connect computers to each other, to the internet and to the wired network.to the internet and to the wired network.

The Wi-Fi TechnologyThe Wi-Fi Technology

Wi-Fi Networks use Radio Technologies to Wi-Fi Networks use Radio Technologies to transmit & receive data at high speed:transmit & receive data at high speed:

• IEEE 802.11bIEEE 802.11b• IEEE 802.11aIEEE 802.11a• IEEE 802.11gIEEE 802.11g

Elements of a WI-FI NetworkElements of a WI-FI Network

• Access Point (AP) - Access Point (AP) - The AP is a wireless LAN The AP is a wireless LAN transceiver or “base station” that can connect one or many transceiver or “base station” that can connect one or many wireless devices simultaneously to the Internet. wireless devices simultaneously to the Internet.

• Wi-Fi cards - Wi-Fi cards - They accept the wireless signal and relay They accept the wireless signal and relay information.They can be internal and external.(e.g PCMCIA information.They can be internal and external.(e.g PCMCIA Card for Laptop and PCI Card for Desktop PC)Card for Laptop and PCI Card for Desktop PC)

• Safeguards - Safeguards - Firewalls and anti-virus software protect Firewalls and anti-virus software protect networks from uninvited users and keep information secure.networks from uninvited users and keep information secure.

How a Wi-Fi Network WorksHow a Wi-Fi Network Works• Basic concept is same as Walkie talkies.Basic concept is same as Walkie talkies.• A Wi-Fi hotspot is created by installing an access point A Wi-Fi hotspot is created by installing an access point

to an internet connection.to an internet connection.• An access point acts as a base station. An access point acts as a base station. • When Wi-Fi enabled device encounters a hotspot the When Wi-Fi enabled device encounters a hotspot the

device can then connect to that network wirelessly.device can then connect to that network wirelessly.• A single access point can support up to 30 users and A single access point can support up to 30 users and

can function within a range of 100 – 150 feet indoors and can function within a range of 100 – 150 feet indoors and up to 300 feet outdoors.up to 300 feet outdoors.

• Many access points can be connected to each other via Many access points can be connected to each other via Ethernet cables to create a single large network.Ethernet cables to create a single large network.

Wi-Fi Network TopologiesWi-Fi Network Topologies• AP-based topology AP-based topology

• Peer-to-peer topology Peer-to-peer topology

• Point-to-multipoint bridge topologyPoint-to-multipoint bridge topology

AP-based topologyAP-based topology

• The client communicate through Access Point. The client communicate through Access Point.

Peer-to-peer topologyPeer-to-peer topology• AP is not required.AP is not required.• Client devices within Client devices within

a cell can a cell can communicate directly communicate directly with each other.with each other.

• It is useful for setting It is useful for setting up of a wireless up of a wireless network quickly and network quickly and easily.easily.

Point-to-multipoint bridge topologyPoint-to-multipoint bridge topology

Wi-Fi ConfigurationsWi-Fi Configurations

Wi-Fi ConfigurationsWi-Fi Configurations

Wi-Fi ConfigurationsWi-Fi Configurations

SECURITY THREATSSECURITY THREATS1.1. Attacker spoofes a Attacker spoofes a

disassociate message disassociate message from the victimfrom the victim

2.2. The victim starts to The victim starts to look for a new access look for a new access point, and the attacker point, and the attacker advertises his own AP advertises his own AP on a different channel, on a different channel, using the real AP’s using the real AP’s MAC addressMAC address

3.3. The attacker connects The attacker connects to the real AP using to the real AP using victim’s MAC addressvictim’s MAC address

Wi-Fi Security Wi-Fi Security

The requirements for Wi-Fi network The requirements for Wi-Fi network security can be broken down into two security can be broken down into two primary components:primary components:

• AuthenticationAuthentication User AuthenticationUser Authentication Server AuthenticationServer Authentication

• PrivacyPrivacy

Wi-Fi ApplicationsWi-Fi Applications

• HomeHome• Small Businesses or SOHOSmall Businesses or SOHO• Large Corporations & CampusesLarge Corporations & Campuses• Health CareHealth Care• Wireless ISP (WISP)Wireless ISP (WISP)• TravellersTravellers

AdvantagesAdvantages• MobilityMobility• Ease of InstallationEase of Installation• FlexibilityFlexibility• CostCost• ReliabilityReliability• SecuritySecurity• Use unlicensed part of the radio spectrumUse unlicensed part of the radio spectrum• RoamingRoaming• SpeedSpeed

LimitationsLimitations

• InterferenceInterference• Degradation in performanceDegradation in performance• High power consumptionHigh power consumption• Limited rangeLimited range