Wi-Fi yog wireless LAN thev naus laus zis raws li IEEE 802.11 tus qauv. Cov khoom siv uas tuaj yeem siv cov thev naus laus zis no suav nrog cov khoos phis tawj tus kheej, game consoles, xov tooj thiab ntsiav tshuaj, lub koob yees duab digital, qee lub TV, audio player, thiab cov tshuab luam ntawv niaj hnub.
Wi-Fi enabled li tuaj yeem txuas rau Is Taws Nem ntawm WLAN thiab wireless hotspot. Cov tom kawg muaj thaj tsam li 20 meters sab hauv tsev thiab ntau sab nraum zoov. Kev pab them nqi nkag tuaj yeem yog me me (ib chav nrog xov tooj cua thaiv phab ntsa) lossis loj heev (ob peb square kilometers), ua tiav los ntawm kev siv ntau qhov sib tshooj nkag.
Qhov no yog dab tsi?
Lub npe ntawm lub wireless network - Wi-Fi - pib siv thaum Lub Yim Hli 1999. Nws yog tsim los ntawm lub tuam txhab kev sab laj Interbrand nrog lub hom phiaj ntawm kev tsim lub npe uas yuav yooj yim rau nco ntsoov.
Lub Wi-Fi Developers Alliance tau siv cov lus tshaj tawm tsis tseem ceeb rau lub sijhawm luv luv tom qab nws tsim cov cim lag luam, uas zoo li "Tus Qauv Wirelessprecision." Nws tau hloov pauv sai sai rau WirelessFidelity.
Nws ua haujlwm li cas?
Cov ntaub ntawv tseem ceeb ntawm Wi-Fi tes hauj lwm yog raws li hauv qab no.
Tus qauv IEEE 802.11 yog txheej txheej ntawm kev tswj hwm kev nkag mus rau hauv xov xwm (MAC) thiab cov txheej txheem lub cev (PHY) cov lus qhia tshwj xeeb rau kev sib txuas lus hauv computer hla lub wireless hauv zos network (WLAN) hauv zaus bands 2, 4, 3, 6, 5 thiab 60 GHz. Lawv raug tsim thiab tswj los ntawm IEEE LAN/MAN Standards Committee (IEEE 802). Cov txheej txheem yooj yim ntawm tus qauv tau tshaj tawm hauv xyoo 1997 thiab tau raug hloov kho tom ntej. Lawv muab lub hauv paus rau cov khoom siv sib txuas wireless siv lub hom Wi-Fi. Txawm hais tias txhua qhov kev hloov kho tau raug tshem tawm thaum nws suav nrog qhov tseeb version ntawm tus qauv, cov tuam txhab ntiaj teb nyiam muag cov kev hloov pauv vim lawv succinctly txhais lub peev xwm ntawm lawv cov khoom. Yog li ntawd, txhua qhov kev hloov pauv yuav dhau los ua nws tus qauv.
Wireless Wi-Fi tes hauj lwm feem ntau siv 2.4 GHz (12 cm) UHF thiab 5.8 GHz (5 cm) UHF xov tooj cua zaus bands. Txhua tus neeg nyob hauv thaj tsam ntawm modem tuaj yeem sim nkag mus rau kev sib txuas. Vim li no, Wi-Fi thiaj li muaj kev cuam tshuam ntau dua li cov xov tooj sib txuas.
Wi-Fi Protected Access yog ib tsev neeg ntawm cov thev naus laus zis tsim los tiv thaiv cov ntaub ntawv txav mus los ntawm cov tes hauj lwm, suav nrog kev sib koom tes ntawm tus kheej thiab koom nrog. Cov yam ntxwv kev ruaj ntseg tau hloov zuj zus mus los muab kev tiv thaiv zoo dua thiab cov txheej txheem tshiab.
Kuv yuav teeb tsa lub wireless Wi-Fi li cas?
Txhawm rau txuas rau Wi-nkaus LAN, koj lub computer yuav tsum tau nruab nrog lub wireless network interface tswj. Kev sib xyaw ua ke ntawm lub khoos phis tawj thiab tus tswj hwm interface yog hu ua chaw nres tsheb. Rau tag nrho cov chaw nres tsheb uas siv ib lub xov tooj cua zaus sib txuas lus channel, kev sib kis ntawm nws tau txais nyob rau hauv qhov ntau. Kev hloov pauv tsis tau lees paub thiab yog li ntawd yog qhov kev siv dag zog zoo tshaj plaws. Ib tus neeg nqa khoom nthwv dej yog siv los xa cov ntaub ntawv. Cov nthwv dej no tau teeb tsa rau hauv pob ntawv xa tawm ntawm Ethernet txuas.
nkag mus hauv internet
Ntawm Wi-Fi thev naus laus zis tuaj yeem siv los muab kev nkag mus rau Is Taws Nem rau cov khoom siv hauv cov teeb liab. Qhov kev pab cuam ntawm ib lossis ntau qhov kev sib txuas ntawm cov ntsiab lus nkag tuaj yeem nyob ntawm thaj chaw me me mus rau ntau qhov square kilometers. Kev pab them nqi tshaj ib cheeb tsam loj yuav xav tau ib pab pawg APs nrog kev sib tshooj.
Wi-Fi muab kev pabcuam hauv tsev ntiag tug, kev lag luam, thiab pej xeem hotspots uas tau teeb tsa tsis pub dawb lossis them nyiaj, feem ntau siv nplooj ntawv web tshwj xeeb los muab kev nkag. Cov koom haum thiab kev lag luam xws li tshav dav hlau, tsev so, thiab tsev noj mov feem ntau muab kev sib txuas dawb los nyiam cov neeg siv khoom.
Routers suav nrog cov neeg siv digital lossis cable modem thiab Wi-Fi hotspot. Lawv feem ntau ntsia hauv cov tsev nyob.thiab lwm lub tsev thiab muab kev siv Internet thiab kev sib txuas rau txhua yam khoom siv txuas nrog lawv wirelessly lossis ntawm cable.
portable routers
Teeb tsa lub wireless Wi-Fi tes hauj lwm kuj tuaj yeem ua tiav ntawm cov khoom siv nqa tau. Roj teeb-powered routers yuav suav nrog xov tooj cua hauv internet thiab Wi-Fi hotspot. Thaum sau npe mus rau lub xov tooj ntawm tes, lawv tso cai rau cov chaw nyob sib ze nkag tau hauv Is Taws Nem ntawm 2G, 3G lossis 4G tes hauj lwm siv cov cuab yeej sib txuas. Ntau lub xov tooj smartphones muaj qhov muaj peev xwm ua tau zoo li no, suav nrog cov raws li Android, BlackBerry, Bada, iOS (iPhone), WindowsPhone, thiab Symbian, txawm hais tias cov neeg nqa khoom feem ntau lov tes taw cov yam ntxwv no lossis them tus nqi los pab nws, tshwj xeeb tshaj yog rau cov neeg siv khoom tsis txwv cov ntaub ntawv.. Qee lub laptops nrog daim npav cellular modem tuaj yeem ua raws li mobile Internet hotspots.
Ad-hoc kev sib txuas
Wi-Fi tes hauj lwm tseem tso cai rau koj sib txuas lus ncaj qha los ntawm ib lub computer mus rau lwm qhov yam tsis muaj qhov nruab nrab. Qhov no yog hu ua tshwj xeeb signaling. Qhov Ad-hoc wireless networking hom no tau ua pov thawj nrov nyob rau hauv multiplayer handheld game consoles xws li Nintendo DS, PlayStation Portable, digital koob yees duab, thiab lwm yam khoom siv hluav taws xob siv. Qee cov khoom siv kuj tuaj yeem siv lawv cov kev sib txuas hauv Is Taws Nem hauv adhoc hom, dhau los ua "hotspots" lossis "virtual routers".
Lwm txoj hauv kev sib txuas lus ncaj qha dhau ntawm Wi-nkaus network yog Tunneled Direct Link Setup (TDLS), uas tso cai rau ob lub cuab yeej ntawm tib lub network sib txuas lus ncaj qha tsis yog los ntawm qhov chaw nkag.
Hardware
Wi-Fi ua rau nws pheej yig dua los txuas cov tes hauj lwm hauv zos. Tsis tas li ntawd, kev sib txuas wireless tuaj yeem muab tso rau qhov twg siv tsis tau cable (xws li cov chaw qhib thiab cov tsev keeb kwm). Txawm li cas los xij, lub tsev phab ntsa ua los ntawm qee yam khoom siv (xws li pob zeb nrog cov ntsiab lus hlau siab) tuaj yeem thaiv Wi-Fi wireless LAN signals.
Cov tuam txhab niaj hnub tsim cov khoom siv sib txuas sib txuas hauv ntau lub laptops. Tus nqi ntawm Wi-Fi chipset tseem poob qis, ua rau nws txoj kev xaiv nyiaj txiag sib txuas nrog rau hauv ntau cov khoom siv.
Ntau hom kev sib tw ntawm cov ntsiab lus nkag thiab cov neeg siv khoom sib txuas sib txuas tuaj yeem cuam tshuam txog qib kev pabcuam. Cov khoom tsim los ua "Wi-Fi Certified" los ntawm Wi-Fi Alliance yog rov qab sib xws. Tsis zoo li lub xov tooj ntawm tes, txhua yam khoom siv yuav ua haujlwm nyob txhua qhov chaw hauv ntiaj teb.
USB adapters
Ib qho chaw nkag wireless (WAP) txuas ib pab pawg ntawm cov khoom siv wireless mus rau ib qho chaw nyob ze ntawm LAN. Nws zoo ib yam li lub network hub, relaying cov ntaub ntawv ntawm cov khoom sib txuas ntxiv rau ib qho (feem ntau) wired txuas nrog gadget, feem ntau yog Ethernet hloov. nwstso cai rau txhua yam khoom siv txuas nrog sib txuas lus.
Wireless adapters tso cai rau cov khoom siv txuas rau lub vev xaib. Lawv synchronize nrog cov khoom siv siv ntau yam kev sib txuas sab nraud lossis sab hauv xws li PCI, miniPCI, USB, ExpressCard, Cardbus, thiab PC Card. Txij li thaum xyoo 2010, feem ntau ntawm cov khoos phis tawj tshiab tshiab tau muaj cov khoom siv ua ke.
Wireless routers koom ua ke qhov chaw nkag, hloov Ethernet, thiab sab hauv router firmware uas muab IP chaw nyob xa mus, NAT, thiab DNS xa mus los ntawm kev tsim WAN interface. Cov cuab yeej no tso cai rau koj los txuas cov xov tooj thiab wireless Ethernet LAN rau cov khoom siv WAN li niaj zaus (xws li cable lossis DSL modem).
Lub wireless router tso cai rau koj los teeb tsa tag nrho peb yam (tsuas yog nkag mus thiab router) los ntawm ib qho chaw siv hluav taws xob. Nws feem ntau yog ib qho kev sib koom ua ke hauv web server nkag mus rau cov xaim thiab wireless LANs, thiab feem ntau rau WAN cov neeg siv khoom. Qhov kev siv hluav taws xob no tseem tuaj yeem yog daim ntawv thov uas khiav ntawm lub khoos phis tawj, ib yam li Apple's AirPort, uas tau tswj hwm siv AirPort Utility ntawm macOS thiab iOS.
Ib lub wireless network txuas txuas txuas txuas txuas mus rau lub wireless network. Nws txawv ntawm qhov chaw nkag: tom kawg txuas cov khoom siv wireless mus rau cable network ntawm qib cov ntaub ntawv txuas. Ob lub wireless txuas tuaj yeem siv los txuas obcable networks hla nws tus kheej kab, uas yog ib qho tseem ceeb nyob rau hauv lub sij hawm uas ib tug wired kev twb kev txuas tej zaum yuav tsis muaj, xws li ntawm ob lub tsev sib cais los yog tej thaj chaw deb qhov chaw.
Lub Dual Band Wireless Choj kuj tseem siv tau los muab 5GHz network ntawm lub cuab yeej uas tsuas yog txhawb nqa 2.4GHz wireless thiab muaj Ethernet cable chaw nres nkoj. Tsis tas li ntawd, ntau yam extensioners lossis repeaters tuaj yeem txuas ntxiv ntau yam ntawm Wi-Fi network uas twb muaj lawm.
Embedded systems
Tsis ntev los no (tshwj xeeb tshaj yog txij li xyoo 2007), cov khoom siv hauv Wi-nkaus tau nthuav tawm ntau thiab ntau dua. Lawv suav nrog lub sijhawm ua haujlwm tiag tiag thiab muab txoj hauv kev yooj yim rau wirelessly txuas txhua lub cuab yeej uas muaj qhov chaw nres nkoj serial thiab xa cov ntaub ntawv los ntawm nws. Qhov no tso cai rau koj los tsim cov cuab yeej tswj tau yooj yim. Ib qho piv txwv yuav yog ib qho khoom siv ECG portable saib xyuas tus neeg mob hauv tsev. Nrog kev txhawb nqa Wi-Fi, nws tuaj yeem sib txuas lus nrog lub khoos phis tawj nyob deb nroog hauv Is Taws Nem.
Cov qauv no yog tsim los ntawm OEMs, yog li cov neeg tsim khoom siv tsuas yog kev paub txog Wi-Fi cov ntaub ntawv tsawg kawg nkaus kom pab lawv cov khoom sib txuas.
Network Security
Qhov teeb meem tseem ceeb ntawm kev ruaj ntseg network wireless yog tias nws yooj yim rau kev nkag mus tau yooj yim dua li cov kab ke ib txwm muaj (xws li Ethernet). Nrog rau kev sib txuas nrog, koj yuav tsum tau nkag mus rau lub tsev (lub cevtxuas mus rau ib lub network sab hauv), los yog tawg los ntawm sab nraud firewall. Txhawm rau qhib Wi-nkaus, koj tsuas yog yuav tsum nyob hauv thaj chaw teeb liab. Feem ntau cov tuam txhab koom tes tiv thaiv cov ntaub ntawv rhiab thiab cov tshuab los ntawm kev sim tsis kam nkag mus rau sab nraud. Ua kom siv thev naus laus zis no txo kev ruaj ntseg yog tias lub network tsis siv encryption.
Wi-Fi Security
Ib qho kev ntsuas los tiv thaiv kev nkag mus los ntawm cov neeg siv tsis tau tso cai yog zais lub npe ntawm qhov chaw nkag los ntawm kev kaw SSID tshaj tawm. Thaum qhov no muaj txiaj ntsig zoo rau cov neeg siv tsis tu ncua, nws tsis tuaj yeem ntseeg tau raws li txoj hauv kev ruaj ntseg vim tias SSID raug xa tawm ncaj qha rau cov lus teb rau cov neeg siv khoom thov. Lwm txoj hauv kev yog tso cai rau cov khoos phis tawj uas paub MAC chaw nyob txuas mus rau Wi-Fi network, tab sis kuj tseem muaj qhov tsis zoo ntawm no. Qee cov cuab yeej mloog tuaj yeem koom nrog hauv lub network los ntawm kev dag ib qho chaw nyob.
Wired Equivalent Privacy (WEP) encryption tau tsim los tiv thaiv kev sib tsoo, tab sis tsis suav tias yog kev nyab xeeb ntxiv lawm. Cov cuab yeej zoo li AirSnort lossis Aircrack-ng tuaj yeem rov qab tau WEP cov yuam sij sai. Vim li no, Wi-Fi Alliance tau pom zoo siv Wi-Fi Protected Access (WPA), uas siv TKIP. Txoj kev tiv thaiv no tau tsim tshwj xeeb los siv rau cov khoom qub qub, feem ntau los ntawm kev hloov kho firmware. Txawm hais tias muaj kev nyab xeeb ntau dua li WEP, WPA kuj pom muaj qhov tsis zoo. Kev ntsuas kev ruaj ntseg ntxivtso cai rau hloov kho qhov thev naus laus zis no.
Txoj kev ruaj ntseg WPA2 siv Advanced Encryption Standard yog thawj zaug hauv xyoo 2004. Nws tau txais kev txhawb nqa los ntawm cov cuab yeej tshiab Wi-Fi feem ntau thiab ua tiav WPA ua raws. Hauv xyoo 2017, qhov tsis txaus ntseeg tau pom nyob rau hauv cov txheej txheem no thiab. Qhov tsis muaj teeb meem cuam tshuam txog kev tawm tsam siv qhov tseem ceeb rov qab hu ua KRACK.
