Gii php mng khng dyMng khng dy (Wreess Network hay W) h thng mng cho php cc thet b} du cu truy cp den h thng mng cuc b, mng Internet thng qua m trung truyen sng Rado. y mt g php m, c rat nheu uu dem so v cc ket n mng c dy (wre ne) truyen thng. Ngu dng van c the duy tr ket n v ton mngkh d chuyen trong vng phu sng. 1.1 Nhu cu v s pht trin ca !"N# Hn nay, ket n mng khng dy dang ngy cng tang v d tro thnh mt nhu cu thet yeu t cc van phng, khch sn, cc h ngh}, h tho.Theo thng k t M th tcd tang truong s ngu dng mng khng dy tang trung bnh 30,9% mt nam (t nam 2002 den 2007). y mt con s dng mng cho cc nh cung cap thet b} mng khng dy. -S uong thet b} du cu duoc tch hop san kh nang ket n mng khng dy ngy cng pho ben (aptop, PDA, .). -Nhu cu thay do v} tr, d chuyen n tuc, cua ngu dng ngy cng tang do yu cu cua cng vc hn d. -Cc ng dung duoc tch hop v tuong thch trong m trung mng khng dy ngy cng da dng (V du nhu dn tho IP, VPN .) -Cc chun ket n mng khng dy ra d, ngy cng chat ch, cho php cc thet b} mng cua cc hng hon ton c the dong b v nhau, tang kh nang ua chon cua khch hng. 1.$1 !%i &ch ca !"N# gii php k't n(i mng khng dy )*m +i ch, khch hng r-t nhi.u +%i &ch v. m/t kinh t' -Tang nang suat m vc cua cc nhn vn, kh ho khng cn b} phu thuc vo 1 v} tr t bn m vc nhu truc, gm mt phn p uc tnh thn cho nhn vn. -Khng mat ch ph cho vc chy dy xung quanh phng m vc bng cp dong, cp quang . -Khng ph bo ch ph m kh d}ch chuyen v} tr m vc cua nhn vn kh thm nhn vn, d}ch chuyen bn m vc ..1.0 1c chu2n !"N# T th ky du, kh cng ngh WLAN m ra d, cc chun WLAN khng chat ch, tc d truyen hn che. en th dem hn t, kh h thng WLAN d pht tren rng d, nheu to chc quan tm den hon. Cc chun WLAN m ra d h tro cho bo mt, tang tc d dung truyen, tang kh nang tuong tc ga sn phm cua cc hng khc nhau tt hon. 1.0.11c chu2n !"N th' h3 th4 nh-t# -802.11 ho cc chun WLAN th kydu, tc d truyen truyen d u t 1-2Mbps. -802.11a chun cho php truyen d u o tc d cao 54Mbps, hot dng o bang tn 5GHz. Do hotdngo bang tn cao cho php gm bt mt s vande ve nhu so v kh hot dng obang tn 2,4GHz. Tuy nhn t mt s quc ga, bang tn 5GHz b} cam de trnh xung dt v cch thng cng cng cng. Cc thet b} cua Norte hot dng che d Turbo mode c the n t 108Mbps. -802.11b chun cho php truyen d u tc d 11Mbps, hot dng o bang tn 2,4Ghz. V bang tn ny, chun 802.11bduoc pht tren rat rng r trn the g. 1.0.$1c chu2n !"N th' h3 th4 hai# -802.11g: chun nyduoc pht tren t chun 802.11b, tuong thchduoc v 802.11b. N hotdngo bang tn 2,4GHz, cho php truyen d u tda 54Mbps. Chun ny dang duoc su dung rng r tuong tu nhu chun 802.11b. -802.11d: Chun qud}nh co che Roamng kh thet b} khng dy d chuyen tvng phu sng ny sang vng phu sng khc. -802.11e: chun ve dm bo chat uong d}ch vu (OoS) trong mng khng dy, kh nang phn o d}ch vu dua trn ng dung, h tro cc ng dung th gan thuc nhu vdeo, voce ... -802.11f: cc khuyen co dng de qu chun thet b} khng dy cua cc hng khc nhau, de chng c the dng chung duoc. -802.11: Chun cho m ho d u trong mng khng dy yu cu bo mt. -802.11x: Co che xc thuc vdeu khen truy nhp dua trn gao thc EAP (Extensbe Authentcaton Protoco). 1.5 Nhu cu ca khch hng khi 6y dng h3 th(ng !"N Ta d bet duoc rng hn nay nhu cu xy dung h thng mng khng dy WLAN rat n. Tuy nhn ta cn ph heu r cc yu cu cua khch hng kh xy dung mt h thng WLAN g?Cc nhu cu d : kh nang bo mt, tnh nh hot, kh nang qun tr}. 1.5.17&nh 8, m9t ca h3 th(ng# An nnh cua h thng WLAN mt van de rat quan trong v un duoc dat n hng du. V mt h thng Wre-ne ta c the d dng kem sot vc cam dy vo mng, nhung v WLAN ta khng the ngan cn vc thu pht sng Rado trong khu vuc phu sng cua mng mnh. Chnh v vy m bo mt van de rat khng the theu duoc trong mt h thng WLAN. Vc dm bo an nnh trong mng WLAN kh hon nheu so v mng LAN thng thung. Bo v mng khng dy ch}u cc hnh thc tan cng nhu mt mng LAN thng thung + cc hnh thc tan cng dac th rng cua mng truyen sng Rado. 1.5.$7&nh +inh h,t ca h3 th(ng# H thng mng WLAN cng nhu mt h thng mngbat ky un d ho tnh nh hot cua h thng trong su dung, bo tr, nng cap. -Mt h thng WLAN tt ph c kh nang cung cap co che chuyen vng (roamng) ga cc AP (Access Pont). eu ny dm bo cho ngu dng ket n cua ngu dng un duoc duy tr n tuc, ke c kh ho d chuyen t vng phu sng cua AP ny sang vng phu sng cua AP khc. -H tro cc ng dung th gan thuc trn mng khng dy nhu Voce, Vdeo, . -C the tn dung duoc cc h thng mng LAN c san cua doanh nghp. -Kh nang d dng mo rng h thng trong tuong a. 1.5.0:h n;ng