Wi-Fi

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    Wi-Fi - Presentation Transcript

    1. ‘Wireless Fidelity’ ‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 1
    2. Wi-Fi is the name given to the IEEE 802.11 wireless networking protocol family. Why Wi-Fi … 1. T rul M O B ILE. y 2. N o D angl C ab l O R W ires. ing es 3. U ses an U N -Licensed part of the R ad io S pectrum , this m eans l ess restrictions in m any countries. Problems… 1. H eavy LAN cannot b e carried out. 2. N etw ork C ongestion. 3. H eavy LAN cannot b e carried . WPA: “W i-F i P rotected Access” a security protocol suite that has repl , aced W EP , using a com pl and untilnow , secure system of authentication. ex, WEP: “W irel ess Equival P rivacy”an ol er security protocol that w as used w id el ent , d y in ol er Aps to provid e security. W EP is now consid ered rel d ativel insecure. y SSID: “S ervice S et Id entifier”is a 32-b it character unique id entifier attached to the , head er of packet transm itted over W LAN . S S ID d ifferentiates one W LAN from one another, so that al AP s and d evices attem pting to connect to a specific W LAN m ust l use the sam e S S ID . It is al referred to as a N ET W O R K N AM E. so ‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 2
    3. Wi-Fi Technical Details: - 1. The term wireless networking refers to technology that enables two or more computers to communicate using standard network protocols. 2. Wi-Fi is the name given to the IEEE 802.11 wireless networking protocol family. 3. The main difference between Wi-Fi and Cellular is that Wi-Fi is implemented in Unlicensed Bands. 4. Wi-Fi networks have limited range. A typical router using 802.11b or 802.11g standards might have a range of about 150 feet (46 meters). Jargon Buster : • Access Point (AP) : It is a piece of Hardware which connects wireless adapters to the backend servers that provide the necessary infrastructure to connect to the Internet. • Wireless Adapter : It is the wireless replacement for the network interface (LAN) card – available in the PCI and PCMCIA interface. • Wireless Bridge : In this mode, two APs can be bridged with each other for communication. It is used when networks of two buildings such as offices are to be connected wirelessly. • WPA : “Wi-Fi Protected Access”, a security protocol suite that has replaced WEP, using a complex, and until now, secure system of authentication. • WEP : “Wireless Equivalent Privacy”, an older security protocol that was used widely in older Aps, to provide security. WEP is now considered relatively insecure. • SSID : Service Set Identifier is a 32-bit character unique identifier attached to the header of packet transmitted over WLAN. SSID differentiates one WLAN from one another. It is also referred to as a NETWORK NAME ‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 3
    4. Seminar Topic – Wireless Fidelity Name – Manan Kakkar WIRELESS FIDELITY T aking into consid eration the recent d evel opm ents in the fiel of d ata com m unication, I d thought that this w as the right pod ium to introd uce to you the l atest technol ogy that this the tal of k C orporate Ind ia, consid ered as the next b ig thing to hit Ind ia after the M ob il B oom , W i-F i certainl e y is m aking its presence fel t. S trol d ow n the l l eisurel surround ings of D el s B usiness cl y hi’ ass hotel and stay connected . s P op in for a quick sw im at M um bai’ hotel s s-stil connected . A coffee b reak is no m ore a excuse to l go O ffl anym ore- Bangalore’ Java C ity range of Coffee Shops and other hangout spots too ine s offer Wi-Fi connectivity. Wi-Fi in simple terms is Wireless LAN or Internet connection. P D As, etc. tod ay are read il provid ing W i-F i connectivity. W el the l y l uxury of sitting b y the pool e sipping col d rinks sid d and surfing on the N et d oes m ake it reasonab l e. Simply Why Wi-Fi… 1. T rul M O B ILE. y 2. N o D angl C ab l O R W ires. ing es 3. C an w ork w ith P D As. 4. D ata R ates of 54 M b ps at 2.4 GH z. 5. C an w ork in 2 m od es : Ad -hoc & B ase S tn. 6. B est suited for C orporates w ith severalem pl oyees m oving around w ith Laptop s. 7. U ses an unl icensed p art of the rad io spectrum , this m eans l ess regulatory control in m any s countries. T he term wireless networking refers to technology that enables tw o or m ore computers to communicate using standard network protocols, b ut w ithout netw ork cab l ing. S trictl speaking, y any technol ogy that d oes this coul b e caled w irel d l ess netw orking. H ow ever our d iscussion tod ay is l ited to w irel im ess LAN s. T his technol ogy, has prod uced a num b er of afford ab l w irel e ess solutions that are grow ing in p opul arity w ith b usiness and school as w el as sop histicated s l applications w here netw ork w iring is im possib l such as in w arehousing or p oint-of-sal hand hel e, e d equipm ent. Getting d ow n to the technical ities, Wi-Fi is the name given to the IEEE 802.11 wireless networking protocol family. T he W i-F i – 802.11b cam e first w orking at 2.4GHz offering 11 Mbps, w el m an’ d esire of m ore l to the d evel l s ed opm ent of 802.11a w hich w orked at 5 GHz b ut gave 54Mbps data rate. T rying to red uce operating frequencies w hil m aintaining the D ata R ate e ‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 4
    5. the 802.11g stand ard w as d evel oped w hich is now w id el used and gives 54Mbps data rate at y 2.4GHz frequency. T he ‘ & ‘ ’ stand ard s are com patib l w ith each other as their operating g’ b e frequencies are sam e. T he m ain difference between cellular technology and Wi-Fi is that cellular system use licensed spectrum, and Wi-Fi is implemented in unlicensed bands. T he econom ic b asis for their im pl entation is therefore com pl y d ifferent. the success of W i-F i has m ad e m any peop l em etel e look to unl icensed sp ectrum as the future of w irel ess access, rather than spectrum l icensed and controled b y l l arge corporations. • Wi-Fi networks have limited range. A typical Wi-Fi home router using 802.11b or 802.11g might have a range of 150 ft (46 m) indoors and 300 ft (92 m) outdoors. W i-F i operates in two modes – Ad-Hoc & Base station. 3 friend s in a park exchanging d ata over their W i-F i enab l Laptops is an exam pl of A d - ed e H oc m od e. An ad -hoc, or peer-to-peer w irel ess netw ork consists of a num b er of com puters each equipped w ith a w ireless netw orking interface card . Each com puter can com m unicate d irectl w ith al of the y l other w irel ess enab l com puters. T hey can share fil and printers this w ay, b ut m ay not b e ab l ed es e to access w ired LA N resources, unl ess one of the com puters acts as a b rid ge to the w ired LA N using specialsoftw are. (T his is caled "b rid ging") l ‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 5
    6. Figure 1: Ad-Hoc or Peer-to Peer Networking. Each com puter w ith a w irel ess interface can com m unicate d irectl w ith al of the others. y l W ith appropriate netw orking softw are supp ort, users on the w irel ess LA N can share fil and es printers l ocated on the w ired LAN and vice versa. W hereas if one of the term inal is connected to an Access P oint w hich is further connected s to a b ackend server is a B ase S tation m od e. In this type of netw ork the access point acts l a hub , provid ing connectivity for the w irel ike ess com puters. It can connect (or "b rid ge") the w irel ess LA N to a w ired LA N , alow ing w irel l ess com puter access to LAN resources, such as fil servers or existing Internet C onnectivity. There are two types of access points: e i. D ed icated Hardware Access Points (H AP ) such as, A ppl e's Airport B ase S tation.H ard w are access points offer com prehensive support of m ost w irel ess features, b ut check your requirem ents carefuly.l ii. Software Access Points w hich run on a com puter equip ped w ith a w irel ess netw ork interface card as used in an ad -hoc or peer-to-peer w irel ess netw ork. ‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 6
    7. Figure 2: Hardware Access Point. W irel ess connected com puters using a H ard w are Access P oint. Figure 3: Software Access Point. W irel ess connected com puters using a S oftw are Access P oint. ‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 7
    8. 1. What is the range of a wireless network? Each access point has a finite range w ithin w hich a w irel ess connection can b e m aintained b etw een the cl ient com puter and the access point. T he actuald istance varies d epend ing upon the environm ent; m anufacturers typicaly state b oth ind oor and outd oor ranges to give a reasonab l l e ind ication of rel l perform ance. Al it shoul b e noted that w hen op erating at the l its of iab e so d im range the perform ance m ay d rop, as the qual of connection d eteriorates and the system ity com pensates. T ypical ind oor ranges are 150-300 feet, b ut can b e shorter if the b uil ing d construction interferes w ith rad io transm issions. Longer ranges are possib l b ut perform ance w il e, l d egrad e w ith d istance. O utd oor ranges are quoted up to 1000 feet, b ut again this d epend s up on the environm ent. T here are w ays to extend the b asic operating range of W irel ess com m unications, b y using m ore than a singl access point or using a w irel e ess rel /extension point. ay 2. How many wireless networked computers can use a single access point? T his d ep end s upon the m anufacturer. S om e hard w are access points have a recom m end ed l it of 10, w ith other m ore expensive access points supporting up to 100 w irel im ess connections. U sing m ore com puters than recom m end ed w il cause perform ance and rel il to suffer. l iab ity S oftw are access points m ay al im pose user l itations, b ut this d epend s upon the specific so im softw are, and the host com puter's ab il to process the required inform ation. ity 3. Can we have more than one access point? Y es, m ul l access p oints can b e connected to a w ired LAN , or som etim es even to a second tip e w irel ess LAN if the access point supports this. In m ost cases, separate access points are interconnected via a w ired LA N , provid ing w irel ess connectivity in specific areas such as offices or classroom s, b ut connected to a m ain w ired LAN for access to netw ork resources, such as fil e servers. ‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 8
    9. Figure 4: Multiple Access Points. W irel ess connected com puters using M ul e Access P oints. tipl If a singl area is too l e arge to b e covered b y a singl access point, then m ul e access points or e tipl extension points can b e used . -- N ote that an "extension point" is not d efined in the w irel ess stand ard , b ut have b een d evel ed b y som e m anufacturers. W hen using m ul e access points, op tipl each access point w irel ess area shoul overl its neighb ors. T his provid es a seam l d ap ess area for users to m ove around in using a feature caled "roam ing. " (S ee the next q uestion for an l exp lanation of R oam ing) S om e m anufacturers prod uce extension points, w hich act as w irel ess rel ays, extend ing the range of a singl access point. M ul e extension points can b e strung together to provid e w irel e tipl ess access to far aw ay l ocations from the centralaccess point. Figure 5: Extension Point. W irel ess connected com puters using an Access P oint w ith an Extension P oint. (Figure) 4. What is Roaming? ‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 9
    10. A w irel ess com puter can "roam " from one access point to another, w ith the softw are and hard w are m aintaining a stead y netw ork connection b y m onitoring the signalstrength from in-range access points and l ocking on to the one w ith the b est qual ity. U sualy this is com pl y l etel transparent to the user; they are not aw are that a d ifferent access point is b eing used from area to area. S om e access point configurations require security authentication w hen sw app ing access points, usualy in the form of a passw ord d ial b ox. l og Access points are req uired to have overl ping w irel ap ess areas to achieve this as can b e seen in the folow ing d iagram : l Figure 6: Roaming. A user can m ove from Area 1 to Area 2 transparentl T he W irel y. ess netw orking hard w are autom aticaly sw aps to the Access P oint w ith the b est signal l . N ot al access points are capab l of b eing configured to support roam ing. Al of note is that any l e so access points for a singl vend or shoul b e used w hen im pl enting roam ing, as there is no e d em officialstand ard for this feature. 5. If my computer is connected to a wireless LAN, can it communicate with computers on a wired LAN as well? T o d o this you w il need som e sort of b rid ge b etw een the w irel l ess and w ired netw ork. T his can b e accom pl ished either w ith a hard w are access point or a softw are access point. H ard w are access points are avail l w ith various types of netw ork interfaces, such as Ethernet or T oken R ing, b ut ab e typicaly require extra hard w are to b e purchased if your netw orking req uirem ents change. If l ‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 10
    11. netw orking requirem ents go b eyond just interconnecting a w ired netw ork netw ork to a sm al l w irel ess netw ork, a softw are access point m ay b e the b est sol ution. A softw are access point d oes not l it the type or num b er of netw ork interfaces you use. It m ay im al alow consid erab l fl so l e exib il in provid ing access to d ifferent netw ork types, such as d ifferent ity types of Ethernet, W irel ess and T oken R ing netw orks. S uch connections are onl l ited b y the y im num b er of sl or interfaces in the com puter used for this task. F urther to this the softw are access ots point m ay incl e significant ad d itional features such as shared Internet access, w eb caching or ud content fil tering, provid ing significant b enefits to users and ad m inistrators. 6. Can we use a wireless network to interconnect two LANs? Y es. W ireless netw orking offers a cost-effective sol ution to users w ith d ifficul physical t instalations such as cam puses, hospital or b usinesses w ith m ore than one l l s ocation in im m ed iate proxim ity b ut separated b y p ub l thoroughfare. T his type of instalation requires tw o access ic l points. Each access point acts as a b rid ge or router connecting its ow n LAN to the w irel ess connection. T he w ireless connection alow s the tw o access points to com m unicate w ith each l other, and therefore interconnect the tw o LAN 's. ‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 11
    12. Figure 7: LAN to LAN Wireless Communications: A H ard w are Access P oint provid ing w irel ess connectivity to l ocalcom puters and a softw are access point. T he softw are access point provid es W ired Ethernet netw ork 2 com puters access to W ired N etw ork 1. N ote that not al hard w are access points have the ab il to d irectl interconnect to another l ity y hard w are access point, and that the sub ject of interconnecting LA N 's over w irel ess connections is al arge and com pl one, and is b eyond the scope of this introd uction. ex 7. How to use a wireless network to share an Internet connection? T o share an Internet connection across a LAN you need tw o things: a. an Internet sharing hard w are d evice or softw are program b . a LAN ‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 12
    13. If your LAN is w irel ess, the sam e criteria appl Y ou need a hard w are or softw are access point and y. a w ireless LAN . Any com puter equip ped w ith a w ireless netw ork card running suitab l Internet e sharing softw are can b e used as a softw are access p oint. A num b er of vend ors offer hard w are access points. A hard w are access point m ay provid e Internet S haring capab il ities to W ired LAN com puters, b ut d oes not usualy p rovid e m uch fl l exib il b eyond very sim pl configurations. ity e Figure 8: Software Access Point. W irel ess connected com puters using a S oftw are Access P oint for shared Internet access. ‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 13
    14. Figure 9: Hardware Access Point. W irel ess connected com puters using a H ard w are Access P oint for shared Internet access. 8. If I have more than one hardware access point, how can I share a single Internet connection? If an existing w ired LAN alread y has an Internet connection, then the hard w are access points sim pl connect to your LAN and alow w irel y l ess com puters to access the existing Internet connection in the sam e w ay as w ired LAN com puters. ‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 14
    15. Figure 10: Multiple Access Points. W irel ess connected com puters using M ul e Access P oints. tipl If there is no existing Internet connection, then this d epend s on the access point: Figure 11: Software Access Point sharing one Internet connection. W irel ess connected com puters using M ul e Access P oints. Al w ired and w irel tipl l ess com puters access the Internet through a singl softw are access point. e (Figure) If an access point provid es som e form of Internet sharing itsel then having m ul e such f, tipl access points connected to a w ired LA N m ay require som e specialconfiguration, or possib l m ay y require an ad d itionalInternet sharing d evice or softw are program . ‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 15
    16. 9. Is it true that wireless networking is only good for laptop computers? Al though w irel ess netw orking offers ob vious b enefits to users of l aptops w ho m ove from location to location throughout the d ay, there are b enefits for users of fixed p osition com puters as w el. M any school and b usinesses have unsuitab l b uil ing l l s e d ayouts or w als that cannot b e w ired l for various reasons m aking it d ifficul or im p ossib l to b uil a w ired netw ork. W irel t e d ess netw orking in these environm ents is a very cost effective al ternative al provid ing future fl so exib il In cases ity. w here a sm al num b er of com puters are separated from a m ain netw ork a w irel l ess l m ay b e ink m ore cost effective than netw ork cab l ing al though the l atter is perfectl feasib l T em porary y e. w ireless LAN s can easil b e created for exhib itions, school or b usiness p rojects, al w ithout any y l trail cab l ing ing. Problems faced by a Wi-Fi network… 1. Security is the biggest concern. T he signalb eing R F is freel transm itted in air, hence anyone in the vicinity of the AP can y access the d ata. T o overcom e w e use S S ID . W P A (W irel ess P rotected Access) is one of the w id el used encryption stand ard , it is a y successor of the W EP (W ireless Equival P rivacy) . ent O ptions such as isol ating the AP s (W ired & W irel ess) can hel p. 2. Network Congestion. 3. Heavy LAN cannot be carried out. ‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 16
    17. George B ush d uring P resend ential D eb ate w as rum oured to have b een using such a d evice ‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 17

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    A brief description about Wi-Fi

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