2 Agenda Introduction Wi-Fi Technologies Wi-Fi Architecture Wi-Fi Network ElementsHow a Wi-Fi Network WorksWi-Fi Network TopologiesWi-Fi ConfigurationsApplications of Wi-FiWi-Fi SecurityAdvantages/ Disadvantages of Wi-Fi
3 IntroductionWireless 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 Network connect computers to each other, to the internet and to the wired network.
4 The Wi-Fi TechnologyWi-Fi Networks use Radio Technologies to transmit & receive data at high speed:IEEE bIEEE aIEEE g
5 802.11 Physical Layer There are three sublayers in physical layer: Direct Sequence Spread Spectrum (DSSS)Frequency Hoping Spread Spectrum (FHSS)Diffused Infrared (DFIR) - Wide angle
6 IEEE Data Link LayerThe data link layer consists of two sublayers :Logical Link Control (LLC)Media Access Control (MAC).uses the same LLC and 48-bit addressing as other 802 LANs, allowing for very simple bridging from wireless to IEEE wired networks, but the MAC is unique to WLANs.
7 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.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.
8 How a Wi-Fi Network Works Basic concept is same as Walkie talkies.A Wi-Fi hotspot is created by installing an access point to an internet connection.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.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.
10 AP-based topology 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 allow roaming.
11 Peer-to-peer topology 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 and easily.
12 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.