Transcript Slide 1
By Kettly Joseph & Stephan Dubissette Overview • OSI Model • Wireless LAN – Definition – Configuration • Bluetooth – Origin and Description – Layers • IEEE802.11 – Origin and Description – layers • • • • Differences and Similarities Conclusion Acknowledgement References OSI Model Bluetooth Example of a connection between client and server Wireless LAN • Definition – Wireless LAN: • Is a flexible data communication network that is used to transmit and receive data over the air by using electromagnetic waves • increases mobility. • Offers the connectivity and the convenience of wired LANs without the need for expensive wiring or rewiring. • Is sometimes more economical to use than wired LAN Wireless LAN • WLAN configuration – Wireless LAN network can be set up in the four following ways: • • • • Independent WLANs Microcells and Roaming Infrastructure WLANs Ad Hoc Bluetooth • Origin – the name “Bluetooth” came from a Viking whose name was King-Harald Blatand – Bluetooth was founded in 1994 • L.M. Ericsson of Sweden • Description – Bluetooth: – Is a Wireless Network Technology – Is a Low power microwave link • Use for short time data transfer • Use for small indoor distances – Devices communicate with each other in an Ad-Hoc fashion Layers (Bluetooth) • Data Layer – Bluetooth devices form overlapping networks called piconets – Each piconet can carry a maximum of eight devices – There are two types of packet transfer: • Asynchronous Connectionless (ACL) links for data transmission • Synchronous Connection oriented (SCO) for audio/ voice transmission. – The Bluetooth data rate has a gross rate of 1 Mbps. Layers (Bluetooth) • Physical Layer Bluetooth: • Operates in the 2.4 GHz unlicensed ISM (Industrial – Scientific – Medical) band • Uses – Gaussian Frequency Shift Keying(GFSK) . – Frequency hopped spread spectrum FHSS) for transmits of data – Data rate is relatively slow at 1 Mbps – Sensitivity Level of -70 dB IEEE802.11 • Origin and description – IEEE 802.11 is the standard set by the IEEE for wireless network connections – Target areas for IEEE 802.11 are inside buildings and also outdoor uses. – There is support for most market applications – Three different data/voice integration • 802.11a : 5Ghz OFDM • 802.11b : 2,4GHz DSSS • 802.11g : 5GHz OFDM • Data Layer Layers (IEEE802.11) – two different ways to configure a network in Wireless LAN: – Ad-hoc • there is no structure • order is maintain using algorithm like the spokesman election algorithm – infrastructure • network uses fixed network access point • To widen the wireless LAN the access points are sometimes connected from one node to the other one by connecting them to landlines. Layers (IEEE802.11) • Physical Layer – Handles the transmission of data between nodes – Use DSSS, FHSS( 2.4 - 2.4835 GHz) – Use IR pulse position modulation (300 428,000 GHz). – Medium access control (MAC) layers • Set of protocols responsible for maintaining order in the use of a shared medium. (CSMA/CA) or VCSM Virtual carrier Sense 's mechanism Problem and Solution Layers (IEEE802.11) • Network Layer – Handle Security in the network by using: – Mobile IP which • Is a way to attain wireless networking • Does not change when it moves form a home network to a foreign network. • Maintains connection with the rest of the network by implementing the forwarding routine – Disadvantage • need of storing and forwarding of packets while the mobile agent is on neither the home nor the foreign network • IP works only for IPv4 Differences and Similarities • Differences – Bluetooth use GFSK (Gaussian Frequency Shift Keying) as opposed to CCK (Complementary Code Keying) in 802.11 – 802.11 users have much more flexibility in using their devices. • The range of most Bluetooth devices is approximately 10 m (33ft). Whereas 802.11has an outdoor range of 300m (1000 ft). – Bluetooth uses Frequency Hopping and 802.11b uses DSSS (Direct Sequence Spread Spectrum) – All 802.11 addressing and access is taken from the Ethernet standard. Whereas, all the addressing is handled by the master of the piconets for Bluetooth. – Bluetooth is being used for device to device data transfer. – 802.11 has become more of an access point for a computer to get on a wired backbone Differences and Similarities • Similarities – Bluetooth and 802.11 are both wireless 'network' technologies. – they both operate in the same 2.4 GHz ISM band. – They both are capable of creating ad-hoc networks – They both connect electronic devices without any wires Conclusion • These two technologies had in fact really different uses and could both add something to the wireless market • Today, attempt to make both Bluetooth and IEEE802.11 work together on a same network • Bluetooth hops through frequencies 640 times faster than 802.11 which causes interference. • To reduce the possibility of interference between Bluetooth and 802.11 products, consider using frequency hopping instead of direct sequence IEEE 802.11 wireless LAN radio cards and access points. • The relatively low power signals of the Bluetooth devices diminish rapidly over longer distances. Acknowledgements • Our thanks go to: – Prof. Yao Wang for her time and patience – For our T.A – Students of the ee3414 class for listening to us References • http://www.ee.mtu.edu/~dmarcham/bluetooth/ref.html • Standards and protocol - IEEE802.11b - by Al petrick [Online]. Available: http://www.csdmag.com/main/2000/06/0006 stand.htm • Bluetooth and IEEE802.11 - by Brent Miller ( October 2001)[Online]. Available : http://www-106.ibm.com/developerworks/wireless/library/wiphone/?t=gr,p=WirelessBuds • 10meters.com (2000-2001) Bluetooth and 802.11: A Tale of Two Technologies. 10Meters.com, San Francisco, CA. [Online]. Available: http://www.10meters.com/blue_802.htmlhttp://www.amigocom.com/ News/news1-2-03.pdf • http://www.amigocom.com/News/news1-2-03.pdf • http://www.dcs.napier.ac.uk/~bill/cisco_presentation/osi31.pdf