WIRELESS NETWORK In wireless network, data are carried byelectrical wave (e.g., radio wave) from one node to another.There is no physical cable/wire connecting one computer to another
History Vic Haves has been called the "father ofWiFi". The term WiFi, first used commercially inAugust 1999,] was coined by a brand-consulting firm called Inter band Corporation . This technology has its origins in a 1985ruling by the US Federal CommunicationsCommission that released the ISM Band forunlicensed use.
Basic Components of Wireless Network
Wireless network hardwaresWired networkNetwork interface cards (NIC)Wireless access point /wireless routerHubsClient BridgesRepeatersSwitchesWireless PC cardsWireless adapterModemsAntennaSignal boosterWired network
The Wired Network Internet connectivity Connection to a serverConnection to other network devices Wireless antenna Wireless network adapters, access points, and routers all utilize an antenna to assist in receiving signals on the WLAN. Some wireless antennas, like those on adapters, are internal to the unit. Other antennas, like those on many access points, are externally visible.
Wireless Signal Boosters Some manufacturers of wireless access points and routers also sell a small piece of equipment called a signal booster. Signal booster serves to increase the strength of the base station transmitter. It improve both wireless network transmission and reception simultaneously.
Network interface cards A hardware component to control the flow of data isknown as network interface card. Also known as adapter card, network card, networkinterface card. A light will indicate that an internal antenna isactivated. Wireless ( Bluetooth NIC) must be installed in eachcomputer.
Major functions of wireless NIC:Sender NIC: Take data from Layer 3 (NetworkLayer).Encapsulate the data into frame.Load the frame to electrical wave.Transmit the electrical wave.Receiver NICperforms the reverse activities
Hub, A device that distributes packets, or blocks of data, inorder to connect more than two computers together, isknown as hub.Switch A switch is a device that learns which machine isconnected to its port by using the PC or other devicesIP,s addressFunction A switch can send a packet directly to a specificdestination, instead of sending it to every computer in anetwork. Reduces the amount of broadcast traffic.
MODEM A wireless modem is a type of modulator whichconnects to a wireless network instead of usingtelephone or cable television lines. Wireless modems are used with computers to connectto the Internet. Connecting a wireless modem to the computer willdirectly connect to your wireless ISP (Internet ServiceProvider).
WIRELESS ROUTER– A wireless router is commonly used to provide access to the Internet or to some other computer network Controls the speed security requirements “Center” of your WiFi network.
Wireless Access Point – Central “wiring” device to connect wireless nodes to wireless/wired network – If a network uses WAP, all computers must communicate via the WAP
PC ADAPTER A PC Card adapter joins anotebook computer to thenetwork. The PC Card is a deviceapproximately the width andheight of a credit cardcompatible with the PCMCIAhardware interface standard.
Wireless Personal Area Network Wireless Personal Area Network (WPANs) interconnect devices within a relatively small area, that is generally within a persons reach. Used to link PDA to computer without hard wire.
WPAN Technology Bluetooth is major technology of WPANs. Well suited to use in small devices. Range of 30 meters.
Wireless Local Area Network (WLAN) WANWide Area Network (National/Global) A wireless local area network (WLAN) links two or more devices over a short distance using a LAN wireless distribution method,Local Area Network usually providing a connection(Campus/Building) through an access point for INTERNET ACCESS
WLAN..Lab/Conference Room Work unethered Improve productivity by saving time (use idle time, minimize meeting prep time) You Have real-time access for urgent messages and key information Wireless Access Point Your Office LAN
Local Area Networks (LAN)Function – wireless equivalent to Ethernet Local Area NetworkBased on IEEE standard 802.11 series 802.11 – 1997, data rates to 2 Mb/s (outdated) 802.11b - 1999, data rates to 11 Mb/s (available now) 802.11g - 2000, data rates to 22 Mb/s (available 2002) 802.11a - emerging, data rates to 54 Mb/s (available late 2001)802.11b is dominant technology being implemented.Part of the specification is the Wired Equivalent Protocol (WEP)designed to protect link layer (over-the-air) traffic attacks 26
WLANs Technology WiFi is best technology of WLAN; Range – several 100 meters WLAN is often used in cities to connect networks in two or more buildings without installing a wired link.
Wireless Mesh Network A wireless mesh network is a wireless network made up of radio waves organized in a mesh topology. Each node forwards messages on behalf of the other nodes.Mesh networks can "self heal", automatically re-routing around a node that has lost power.
WMN Applications US military forces useit to connect computersin field operation. Students use wirelessmesh network toexchange files althoughthey lack wiredconnection.
Wireless Metropolitan Area Network Wireless Metropolitan Area Networks are atype of wireless network that connects several wireless local area networks. WiMAX is a type of Wireless MAN and is described by the IEEE 802.16 standard
WMANs..Wireless Metropolitan Area Network is also known as Wireless Local Loop (WLL) Wireless local loop can reach effective transfer speeds of 1 to 10 Mbps within arange of 4 to 10 kilometres, which makes it useful mainly for telecommunications companies.
Wireless Wide Area Network Wireless Wide Area Networks are wireless networks that typically cover large areas, such as between neighboring towns and cities, or city and suburb.Most common - all mobile phones are connected to a wireless wide area network.
Started with cell phones – many technologies & standards Progressed through WAN multiple generationsWide Area Network (National/Global) Analog voice phones Digital voice phones Web-enabled phones Despite multiple generations, technology is still immature and changing dynamically (e.g., web access from a cell phone)
Main Technologies GSM (Global system for Mobile Communication) GPRS (General Packet Radio Service)UMTS (Universal Mobile Telecommunication system)
Global System for Mobile Communication (GSM) -- a digital mobile telephone system used in Europe and other parts of the world General Packet Radio Service (GPRS) -- a packet-based wireless communication service that provides continuous connection to the Internet for mobile phone and computer users
Continued........... Universal Mobile Telecommunications System (UMTS) -- a broadband, packet-based system offering a consistent set of services to mobile computer and phone users no matter where they are located in the world
Mobile Devices NetworkWith the development of smart phones , cellular telephone networks routinely carry data in addition to telephone conversations Global system of communication Personal communication Services Digital Advanced Mobile Phone Service
Wireless network Speed And RangeWireless network speed depends on:– The wireless network technology standard– The distance between sender and receiver, or between a node and a Wireless Access Point– Interference from other wireless devices or electronic devices (e.g., wireless phone)– The presence of solid object (especially metal object, electronic appliance) between the sender and receiver, or between a node and a Wireless Access Point
Wireless Network RangeTo increase the wireless network range: Using “signal booster” Using Wireless Access Point instead of using ad-hoc mode, use infrastructure mode Using MULTIPLE Wireless Access Points
Wireless Network Standards Two major wireless network technology standards: IEEE 802.11 Wireless Fidelity (WiFi) IEEE 802.15 Bluetooth
WiFi.....WiFi is a popular technology that allows anelectronic device to exchange data wirelessly using Radio signals over computer network including internet connection.
Wireless Network StandardsIEEE 802.11– Wi-Fi Most popular All Wi-Fi standards (802.11, a, b, g) have the following features: Communication mode: supporting Ad-hoc and Infrastructure SSID
Wireless Network StandardsWi-Fi: – Includes: 802.11 – The oldest – Maximum throughput: 2 Mbps – Maximum distance between sender and receiver (node and WAP): 150 feet 802.11 b – Maximum throughput: 11 Mbps – Maximum distance between sender and receiver (node and WAP): 300 feet
Wireless Network Standards Wi-Fi: 802.11 a Developed after 802.11 b Maximum throughput: 54 Mbps Problem: NOT compatible with the “popular” 802.11 b Maximum distance between sender and receiver (node and WAP): 150 feet 802.11g Maximum throughput: 54 Mbps Maximum distance between sender and receiver (node and WAP): 300 feet
RANGE Wi-Fi networks have limited range. A typical wireless access point using 802.11b or802.11g with a stock antenna might have a range of 32 m (120 ft) indoors and 95 m (300 ft) outdoors.
USES All stations share a single radio frequency communication channel Transmissions on this channel are received by all stations within range. The hardware does not signal the user that thetransmission was delivered and is therefore called a best effort security mechanism
BLUETOOTHBluetooth is an open standard for short- distance of digital voice & data
Wireless Network Standards: BluetoothBluetooth:Technology of WPANShort-range networkIts speed is 4 Mbps
RANGEMaximum distance between sender and receiver: 33 feet (10 meters) 2.4 GHz frequency
Wireless Network SecurityThree basic wireless network security methods: – SSID (Service Set IDentification) – MAC Address Filtering – Encryption
Controlling Access to a WLANAccess is controlled by limiting a device’saccess to the access point (AP)Only devices that are authorized canconnect to the APOne way: Media Access Control (MAC) addressfiltering
MAC Address Filtering
Wired Equivalent Privacy (WEP)Designed to ensure that only authorizedparties can view transmitted wirelessinformationUses encryption to protect trafficWEP was designed to be:Efficient and reasonably strong 58
WEP KeysWEP secret keys can be 64 or 128 bits longThe AP and devices can hold up to fourshared secret keysOne of which must be designated as the defaultkey
Device AuthenticationBefore a computer can connect to a WLAN,it must be authenticatedTypes of authentication in 802.11Open system authentication • Lets everyone inShared key authentication • Only lets computers in if they know the shared key
Personal Wireless Security WPA Personal Security WPA2 Personal Security
WPA Personal SecurityIn 2002, the WECA organization changed its nameto Wi-Fi (Wireless Fidelity) AllianceIn October 2003 the Wi-Fi Alliance introduced Wi-Fi Protected Access (WPA)WPA had the design goal to protect both present and futurewireless devices, addresses both wireless authenticationand encryptionPSK addresses authentication and TKIPaddresses encryption
WPA2 Personal SecurityWi-Fi Protected Access 2 (WPA2)Introduced by the Wi-Fi Alliance in September2004The second generation of WPA securityStill uses PSK (Pre-Shared Key) authenticationBut instead of TKIP encryption it uses a strongerdata encryption method called AES-CCMP
Web-based WAP Configuration Utility
Wired (Cabled) Network versus Wireless Network Advantages of Wireless Network over Wired (Cabled) Network Mobility: Users can roam around the network without being disconnected Installation speed and cost: Building wireless medium to large network is usually faster and cheaper than building wired (cabled) medium to large network because there is no need to pull cable through walls and ceilings Reach of network: Wireless network can be extended to places where wire/cable cannot reach Flexibility/scalability: New computers can be added easily without having to pull cable into the computers
Disadvantages of Wireless Network Speed: In general, wireless network technology is slower than wired network technologySecurity: In general, wireless network is less secured than wired network
Applications of Wireless Network
Cellular phones and pagers -- provide connectivity for portable and mobile applications, both personal and business Global Positioning System (GPS) -- allows drivers of cars and trucks, captains of boats and ships, and pilots of aircraft to ascertain their location anywhere on earth
Cordless computer peripherals -- the cordless mouse is a common example; keyboards and printers can also be linked to a computer via wireless Cordless telephone sets -- these are limited-range devices, not to be confused with cell phones
Home-entertainment-system control boxes -- the VCR control and the TV channel control are the most common examples; some hi-fi sound systems and FM broadcast receivers also use this technology Remote garage-door openers -- one of the oldest wireless devices in common use by consumers; usually operates at radio frequencies
Two-way radios -- this includes Amateur and Citizens Radio Service, as well as business, marine, and military communications Baby monitors -- these devices are simplified radio transmitter/receiver units with limited range
Satellite television -- allows viewers in almost any location to select from hundreds of channels Wireless LANs or local area networks -- provide flexibility and reliability for business computer users
Portable wireless -- the operation of autonomous, battery-powered wireless devices or systems outside the office, home, or vehicle; examples include handheld cell phones and PCS units IR wireless -- the use of devices that convey data via IR (infrared) radiation; employed in certain limited-range communications and control systems