Subnet Masks thiab Subnetting
Ib lub subnet tso cai rau kev khiav tsheb ntawm cov kev sib tshuam hauv network los ntawm kev sib cais raws li lub network configuration. Los ntawm kev koom nrog cov tswvcuab hauv cov pab pawg neeg muaj tswv yim, subnetting tuaj yeem txhim kho kev ruaj ntseg thiab kev ua haujlwm.
Subnet Mask
Tej zaum qhov tseem ceeb tshaj plaws ntawm subnetting yog lub khwb qhov ncauj qhov ncauj . Zoo li tus IP chaw , ib daim npog lub subnet muaj plaub bytes (32 khoom) thiab feem ntau yog siv cov cim "dotted-decimal".
Piv txwv li, ib qho ntsej muag ntau lub vas npliag hauv nws cov sawv cev ntawm binary :
- 11111111 11111111 11111111 00000000
Feem ntau pom tshwm hauv qhov sib npaug, cov ntawv nyeem tau zoo dua:
- 255.255.255.0
Thov ib daim npog Subnet
Ib daim npog lub subnet tsis ua haujlwm zoo li IP chaw nyob lossis nws tsis muaj nws tus kheej. Xwb, subnet masks nrog tus IP chaw nyob thiab ob qhov tseem ceeb ua hauj lwm ua ke. Thov lub npog ntsej muag subnet rau qhov IP chaw faib qhov chaw nyob rau hauv ob qho chaw, ib qhov chaw nyob txuas xov tooj thiab ib qhov chaw nyob.
Rau ib daim npog lub subnet kom siv tau, nws cov khoom seem sab nrauv yuav tsum tau teem rau '1'. Piv txwv li:
- 00000000 00000000 00000000 00000000
Yog ib qho tsis muaj kev ruaj ntseg subnet ntsej muag vim hais tias qhov tsawg kawg nkaus me ntsis yog teem rau '0'.
Tshaj ntawd, cov khoom me me nyob hauv ib lub looj ntsej muag subnet yuav tsum tau teem rau '0', tsis yog '1'. Yog li no:
- 11111111 11111111 11111111 11111111
Yog tsis muaj tseeb.
Txhua qhov siv tau lub qhov ncauj qhov ntswg muaj ob ntu: sab laug sab nraud nrog txhua lub npog ntsej muag rau '1' (txuas ntxiv network) thiab sab xis nrog tag nrho cov khoom rau '0' (tus tswv tsev feem), xws li thawj tus qauv saum toj no .
Subnetting hauv Xyaum
Subnetting ua hauj lwm los ntawm kev siv lub tswv yim ntawm kev sib txuas lus txuas mus rau lub tshuab computer (thiab lwm qhov chaw network) chaw nyob. Ib lub chaw txuas txuas ntxiv muaj xws li ib qhov chaw nyob hauv network thiab cov khoom ntxiv uas sawv cev rau subnet naj npawb . Ua ke, cov lus qhia ob ntawm no txhawb ob theem kev sib tham uas pom tau los ntawm tus qauv siv ntawm IP.
Lub chaw nyob network thiab tus xov tooj ntawm subnet, thaum ua ke nrog tus neeg tuaj yeem chaw nyob , yog li pab txhawb peb lub tswv yim.
Xav txog qhov piv txwv nram qab no. Ib lub lag luam me kev lag luam siv lub network 192.168.1.0 rau nws cov khoom sab hauv ( intranet ). Lub chaw pabcuam pejxeem xav kom lawv lub computer mus rau ib qhov kev txwv ntawm lub network vim lawv khaws cov ntaub ntawv them nyiaj thiab lwm cov ntaub ntawv ua haujlwm rau cov neeg ua haujlwm. Tab sis vim qhov no yog Class C network, lub npog lub npog nruab nrab ntawm 255.255.255.0 tso cai rau tag nrho cov computers hauv lub network los ua cov phooj ywg (xa cov lus sib tham ncaj qha mus rau ib leeg) ua ntej.
Thawj plaub khoom ntawm 192.168.1.0 -
1100
Muab qhov chaw txuas rau hauv chav kawm C thiab tseem kho qhov ntev ntawm qhov chaw nyob ntawm 24 teev. Rau subnet no network, ntau tshaj 24 khoom yuav tsum tau teem rau '1' ntawm sab laug ntawm lub npog qhov ncauj. Piv txwv, daim npog 25-ntsis 255.255.255.128 tsim ob-subnet network raws li qhia hauv daim ntawv 1.
Rau txhua tus me ntsis ntxiv rau '1' hauv daim npog qhov ncauj, lwm tus me ntsis ua muaj nyob hauv tus xov tooj subnet rau index ntxiv subnets. Ib tug xov tooj ob-ntsis subnet muaj peev xwm txhawb nqa txog plaub subnets, ib tug xov tooj-peb-npawb txhawb nqa txog yim lub subnets, thiab ntxiv rau.
Cov Haujlwm Ntiag Tug thiab Thaj Chaw
Raws li tau hais ua ntej ntawm qhov kev qhia no, pawg tswj hwm uas tswj cov kev cai lij choj hauv Internet tau muab qee cov kev sib txuas rau hauv kev siv sab hauv.
Feem ntau, intranets siv khiav cov tes hauj lwm no tau tswj ntau txoj kev tswj lawv tus IP configuration thiab siv Internet. Tham nrog RFC 1918 kom paub ntau ntxiv txog cov kev sib txuas lus tshwj xeeb no.
Txoj kev xaus
Subnetting pub rau cov neeg khiav dej num hauv ib qho yooj yim hauv kev txheeb xyuas cov kev sib raug zoo ntawm cov chaw ntaus network. Hosts on sib txawv subnets tsuas sib tham tau sib txuas los ntawm kev sib txuas lus tshwj xeeb network xws li routers . Lub peev xwm los lim cov tsheb ciav hlau ntawm subnets tuaj yeem ua ntau dua bandwidth muaj rau cov ntawv thov thiab txo tau kev nkag tau rau hauv cov kev ntshaw.