Wi-Fi Technology

Agenda Introduction Introduction History History Wi-Fi Technologies Wi-Fi Technologies Wi-Fi Network Elements Wi-Fi Network Elements How a Wi-Fi Network Works How a Wi-Fi Network Works Wi-Fi Network Topologies Wi-Fi Network Topologies Wi-Fi Configurations Wi-Fi Configurations Applications of Wi-Fi Applications of Wi-Fi Wi-Fi Security Wi-Fi Security Advantages/ Disadvantages of Wi-Fi Advantages/ Disadvantages of Wi-Fi

Introduction Wireless Technology is an alternative to Wired Technology, which is commonly used, for connecting devices in wireless mode. Wireless Technology is an alternative to Wired Technology, which is commonly used, for connecting devices in wireless mode. Wi-Fi (Wireless Fidelity) is a generic term that refers to the IEEE communications standard for Wireless Local Area Networks (WLANs). Wi-Fi (Wireless Fidelity) is a generic term that refers to the IEEE communications standard for Wireless Local Area Networks (WLANs). Wi-Fi Network connect computers to each other, to the internet and to the wired network. Wi-Fi Network connect computers to each other, to the internet and to the wired network.

History In 1991 Wi-Fi was invented by NCR Corporation / AT & T. In 1991 Wi-Fi was invented by NCR Corporation / AT & T. Under the name WaveLAN with speeds of 1Mbps/2Mbps. Under the name WaveLAN with speeds of 1Mbps/2Mbps. Initially meant for Cashier systems. Initially meant for Cashier systems. Vic Hayes who is the inventor of Wi-Fi has been named 'father of Wi-Fi’. Vic Hayes who is the inventor of Wi-Fi has been named 'father of Wi-Fi’. In 1997 the Institute of Electrical and Electronic Engineers (IEEE) worked out the standard. In 1997 the Institute of Electrical and Electronic Engineers (IEEE) worked out the standard.

The Wi-Fi Technology Wi-Fi Networks use Radio Technologies to transmit & receive data at high speed: IEEE b IEEE b IEEE a IEEE a IEEE g IEEE g

IEEE b Appear in late 1999 Appear in late 1999 Operates at 2.4GHz radio spectrum Operates at 2.4GHz radio spectrum 11 Mbps (theoretical speed) - within 30 m Range 11 Mbps (theoretical speed) - within 30 m Range 4-6 Mbps (actual speed) 4-6 Mbps (actual speed) feet range feet range Most popular, Least Expensive Most popular, Least Expensive Interference from mobile phones and Bluetooth devices which can reduce the transmission speed. Interference from mobile phones and Bluetooth devices which can reduce the transmission speed.

IEEE a Introduced in 2001 Introduced in 2001 Operates at 5 GHz (less popular) Operates at 5 GHz (less popular) 54 Mbps (theoretical speed) 54 Mbps (theoretical speed) Mbps (Actual speed) Mbps (Actual speed) feet range feet range More expensive More expensive Not compatible with b Not compatible with b

IEEE g Introduced in 2003 Introduced in 2003 Combine the feature of both standards (a,b) Combine the feature of both standards (a,b) feet range feet range 54 Mbps Speed 54 Mbps Speed 2.4 GHz radio frequencies 2.4 GHz radio frequencies Compatible with ‘b’ Compatible with ‘b’

Elements of a WI-FI Network Access Point (AP) - The AP is a wireless LAN transceiver or “base station” that can connect one or many wireless devices simultaneously to the Internet. Access Point (AP) - The AP is a wireless LAN transceiver or “base station” that can connect one or many wireless devices 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 for Desktop PC) 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 for Desktop PC) Safeguards - Firewalls and anti-virus software protect networks from uninvited users and keep information secure. Safeguards - Firewalls and anti-virus software protect networks from uninvited users and keep information secure.

How 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 to an internet connection. A Wi-Fi hotspot is created by installing an access point 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 device can then connect to that network wirelessly. When Wi-Fi enabled device encounters a hotspot the device can then connect to that network wirelessly. A single access point can support up to 30 users and can function within a range of 100 – 150 feet indoors and up to 300 feet outdoors. A single access point can support up to 30 users and can function within a range of 100 – 150 feet indoors and up to 300 feet outdoors. Many access points can be connected to each other via Ethernet cables to create a single large network. Many access points can be connected to each other via Ethernet cables to create a single large network.

Wi-Fi Network Topologies AP-based topology (Infrastructure Mode) AP-based topology (Infrastructure Mode) Peer-to-peer topology (Ad-hoc Mode) Peer-to-peer topology (Ad-hoc Mode) Point-to-multipoint bridge topology Point-to-multipoint bridge topology

AP-based topology The client communicate through Access Point. The client communicate through Access Point. BSA-RF coverage provided by an AP. BSA-RF coverage provided by an AP. ESA-It consists of 2 or more BSA. ESA-It consists of 2 or more BSA. ESA cell includes 10-15% overlap to allow roaming. ESA cell includes 10-15% overlap to allow roaming.

Peer-to-peer topology AP is not required. AP is not required. Client devices within a cell can communicate directly with each other. Client devices within a cell can communicate directly with each other. It is useful for setting up of a wireless network quickly and easily. It is useful for setting up of a wireless network quickly and easily.

Point-to-multipoint bridge topology This is used to connect a LAN in one building to a LANs 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.

Wi-Fi Configurations

Wi-Fi Applications Home Home Small Businesses Small Businesses Large Corporations & Campuses Large Corporations & Campuses Health Care Health Care Wireless ISP (WISP) Wireless ISP (WISP) Travellers Travellers

Wi-Fi Security Threats Wireless technology doesn’t remove any old security issues, but introduces new ones Wireless technology doesn’t remove any old security issues, but introduces new ones Eavesdropping Eavesdropping Man-in-the-middle attacks Man-in-the-middle attacks Denial of Service Denial of Service

Eavesdropping Easy to perform, almost impossible to detect Easy to perform, almost impossible to detect By default, everything is transmitted in clear text By default, everything is transmitted in clear text Usernames, passwords, content... Usernames, passwords, content... No security offered by the transmission medium No security offered by the transmission medium Different tools available on the internet Different tools available on the internet Network sniffers, protocol analysers... Network sniffers, protocol analysers... Password collectors Password collectors With the right equipment, it’s possible to eavesdrop traffic from few kilometers away With the right equipment, it’s possible to eavesdrop traffic from few kilometers away

MITM Attack 1. Attacker spoofes a disassociate message from the victim 2. The victim starts to look for a new access point, and the attacker advertises his own AP on a different channel, using the real AP’s MAC address 3. The attacker connects to the real AP using victim’s MAC address

Denial of Service Attack on transmission frequecy used Attack on transmission frequecy used Frequency jamming Frequency jamming Not very technical, but works Not very technical, but works Attack on MAC layer Attack on MAC layer Spoofed deauthentication / disassociation messages Spoofed deauthentication / disassociation messages can target one specific user can target one specific user Attacks on higher layer protocol (TCP/IP protocol) Attacks on higher layer protocol (TCP/IP protocol) SYN Flooding SYN Flooding

Wi-Fi Security The requirements for Wi-Fi network security can be broken down into two primary components: The requirements for Wi-Fi network security can be broken down into two primary components: Authentication Authentication  User Authentication  Server Authentication Privacy Privacy

Authentication Keeping unauthorized users off the network Keeping unauthorized users off the network User Authentication User Authentication Authentication Server is used Authentication Server is used Username and password Username and password Risk: Risk: Data (username & password) send before secure channel established Data (username & password) send before secure channel established Prone to passive eavesdropping by attacker Prone to passive eavesdropping by attacker Solution Solution Establishing a encrypted channel before sending username and password Establishing a encrypted channel before sending username and password

Authentication (cont..) Server Authentication Server Authentication Digital Certificate is used Digital Certificate is used Validation of digital certificate occurs automatically within client software Validation of digital certificate occurs automatically within client software

Advantages Mobility Mobility Ease of Installation Ease of Installation Flexibility Flexibility Cost Cost Reliability Reliability Security Security Use unlicensed part of the radio spectrum Use unlicensed part of the radio spectrum Roaming Roaming Speed Speed

Limitations Interference Interference Degradation in performance Degradation in performance High power consumption High power consumption Limited range Limited range