Sơ lược về công nghệ WIFI & WIMAX

MNG KHNG DY

S lc v cng ngh WIFI & WIMAXLp cao hc CH10CNK1Ging vinPhm Th Qu.Nhm thc hin:ng Tuyt Chinh.Nguyn L Phng.V Th Mai.Phm Th Trang.ng c DngNguyn H Nguyt.

Ni dung trnh byWiFiWIFIKhi nim wifiDng chun 802.11Hot ng ca mng wifiTn s hot ngGii hn v mnh tn hiuTc d liu bng thngKnhCc tham s cu hnhim truy cp khng dy v nh tuynBo mt trong mng wifiBo mt bng WEP (Wired Equivalent Privacy)Bo mt bng WPA (Wifi Protected Access )Tng cng bo mt vi chun 802.11iPhng php ti u v mt s bin php gi mng Wifi an tonKt lunWiFiTNG QUAN V MNG KHNG DYMng khng dy l gu im:Nhc im:Phn loi mng khng dyCc m hnh mng khng dyM hnh mng AD-HOCM hnh mng INFRASTRUCTUREWiMAXTng quan v WiMaxCc chun WiMAXChun 802.16Cu trc mng (Network Topology)Chng giao thc (Protocol stack)Cng ngh iu chCng ngh song cng.Cng ngh ghp knhCht lng dch vuCc chun b sung ca WiMAXVn bo mtCc im yu trong bo mt ca WiMAXBin php tng cng bo mt cho WiMAXKt lunu im v ng dngWIFIMNG KHNG DYGiao tip thng qua sng v tuyn khng cn kt ni vt l . Da trn cng ngh 802.11

H thngMng Khng dyMng C dyTc 11/54/108Mbps10/100/1000MbpsBo mtBo mt khng m bo bng c dy do pht sng thng tin ra mi phaBo mt m bo ch b l thng tin nu can thip thng vo v tr dy dnThi cng v trin khaiThi cng trin khai nhanh v d dngPhc tp do phi thit k i dy cho ton b h thngKh nng m rngKh nng m rng khong cch tt vi chi ph hp li hi chi ph cao khi mun m rng h thng mng c bit l m rng bng cp quangTnh mm doCc v tr kt ni mng c th thay i m khng cn phi thit k liCc v tr thit k khng c ng phi thit k li nu thay i cc v tr kt ni mng

Phn loi mng khng dyDa trn vng ph sng

Da trn cc cng ngh mngKt ni s dng tia hng ngoi. S dng cng ngh Bluetooth. Kt ni bng chun Wi-fi.

WIFIKhi nim WifiDng chun 802.11Hot ng ca mng WifiBo mt trong mng WifiLi ch v ng dng ca Wifi

Khi nim WifiWi-Fi vit tt t Wireless Fidelity hay mng 802.11S dng sng v tuyn, ging nh in thoi di ng, truyn hnh v radio.Cho php truy cp internet ti nhng khu vc c sng ca h thng m khng cn cp ni: sn bay, qun caf, th vin, vn phng, nh ring3 chun thng dng ca WiFi hin nay l 802.11a/b/gM hnh TCP (wifi)Slide ny cn b sung (Kin trc.M hnh TCP nm tng.)

Dng chun 802.11802.11 c pht trin t nm 1997 bi nhm IEEE (M)IEEE 802.11 gm c 4 chun trong h 802.11 v 1 chun ang th nghim:802.11 - l chun IEEE gc ca mng khng dy (hot ng tng s 2.4GHz, tc 1 Mbps 2Mbps). 802.11b - (pht trin vo nm 1999, hot ng tng s 2.4-2.48GHz, tc t 1Mpbs - 11Mbps).802.11a - (pht trin vo nm 1999, hot ng tng s 5GHz 6GHz, tc 54Mbps)

Dng chun 802.11802.11g - (mt chun tng t nh chun b nhng c tc cao hn t 20Mbps - 54Mbps, hin ang ph bin nht). 802.11e - l phin bn th nghim cung cp c tnh QoS (Quality of Service) v h tr MultimediaThc t cn mt vi chun khc thuc h 802.11 l: 802.11F, IEEE 802.11h, IEEE 802.11j, IEEE 802.11d, IEEE 802.11sHot ng ca mng wifiTruyn thng qua mng khng dy l truyn thng v tuyn hai chiu:Thit b adapter khng dy (hay b chuyn tn hiu khng dy) ca my tnh chuyn i d liu sang tn hiu v tuyn v pht nhng tn hiu ny i bng mt ngten.

Thit b router khng dy nhn nhng tn hiu ny v gii m chng. N gi thng tin ti Internet thng qua kt ni hu tuyn Ethernet.

Tn s v knh C hai tn hiu tn s hin ang c s dng:2.4 GHz - Bao gm 14 knh, mi ln vi mt bng thng ca MHz hot ng khong 20-22 trong bng ISM. 5 GHz - Bao gm 13 knh, mi ln vi mt bng thng ca cc hot ng khong 20 MHz trong bng U-NII.

Cc c tnh ca mng wifi802.11a802.11b802.11g802.11nTc ti a54Mbps11Mbps54Mbps300Mbps hay cao hnDi tn s trung tn (RF)5GHz2,4GHZ2,4GHZ2,4GHz hay 5GHz rng bng thng 20MHz20MHz20MHz20 MHz hay 40 MHz

Bo mt trong mng wifiChun WifiBo mtIEEE 802.11, IEEE 802.1x,WEP, WEP2IEEE 802.11i,..WPA, WPA2MAC

Bo mt bng WEPS dng stream cipher RC4 cng vi mt m 40 bit v mt s ngu nhin 24 bit (initialization vector - IV) m ha thng tin.Thng tin m ha c to ra bng cch thc hin operation XOR gia keystream v plain text.Thng tin m ha v IV s c gi n ngi nhn. Ngi nhn s gii m thng tin da vo IV v kha WEP bit trc.

Bo mt trong mng wifi (tip) Bo mt trong mng wifi (tip)Bo mt bng WPA: ci tin hn WEPS dng mt kha ng m c thay i mt cch t ng nh vo giao thc TKIPCho php kim tra xem thng tin c b thay i trn ng truyn hay khng nh vo MIC message.Cho php multual authentication bng cch s dng giao thc 802.1x.Tng cng bo mt vi chun 802.11i (WPA 2)S dng thut ton m ha AES (Advanced Encryption Standard)

WiMAXTng quan v cng ngh WiMAXWiMax (Worldwide Interoperability for Microwave Access) .Mng khng dy bng thng rng.S dng k thut sng v tuyn kt ni cc my tnh.

Tng quan v cng ngh WiMAXc im.Cu trc mm do.Cht lng dch v QoS.Trin khai nhanh.Dch v a mc.Tnh tng thch.Di ng.Li nhun.Ph sng rng hn.Dung lng caoCc chun WiMAX

Chun 802.16H thng truy cp khng dy c nh (FBWA).Hot ng trn di tn c cp php 10-66GHz.Ch s dng cho cc kt ni (tm nhn thng) line of sight (LOS)Cu trc mng (Network Topology)Point to point.Point to multipoint.Thnh phn:Trm c s WiMAX (base station - BS) Trm thu bao (subscriber - SS)

Chng giao thc (Protocol stack)MAC (tng lin kt d liu) Service-specific convergence (hi t) sublayer.MAC common part sublayer (CPS).Security sublayer.PHY (tng vt l).

Cng ngh iu ch

Cng ngh song cngPhn tn(FDD).Phn thi (TDD).Cng ngh ghp knhTDM time division multiplexing.TDMA (time division multiple access).Cht lng dch vuUnsolicited grant services (UGS).Real-time polling services (rtPS).Nonreal-time polling services (nrtPS).Best-effort (BE) services.Vn bo mtCc im yu trong bo mt ca WiMAXLp vt l v lp con bo mt:D b tn cng bi cc phng thc tn cng Jamming v Scrambling.Lp con bo mt c mc ch chnh l bo v cc nh cung cp dch v ngn chn vic n cp dch v.Khng phi l bo v nhng ngi s dng (NSD) dch v.n cp ID.Vn nhn thc ln nhauCc chng nhn cho cc nh sn xut.Cc chng nhn SS.Khng c chng nhn cho BS.Mt s vn khcCc nh ngha khng r rng.D liu ringQun l kha.Cc im yu khc

Bin php tng cng bo mt cho WiMAXNhn thc ln nhauCc li bo v d liuDES-CBC cho m ha d liu.Ci thin bo mt tch hp trong 802.16ePKMv2 s c s dng thay th cho PKM.EAP (Extensible Authentication Protocol).u im v ng dngBackhaul.Last mile.Cu trc mm do.Cht lng dch v QoS.Trin khai nhanh.Dch v a mc.Tnh tng thch.Di ng.Li nhun.Ph sng rng hn.Dung lng cao.Tnh m rng.Bo mt.