Nyob rau xyoo tas los no, fiber ntau rau lub tsev (FTTH) tau pib muaj nqis los ntawm cov tuam txhab sib txuas lus thoob ntiaj teb, thiab cov thev naus laus zis pab tau tab tom tsim kho sai. Muaj ob hom kab ke tseem ceeb rau kev sib txuas FTTH broadband. Cov no yog Active Optical Network (AON) thiab Passive Optical Network (PON). Txog tam sim no, feem ntau FTTH kev xa tawm hauv kev npaj thiab kev xa tawm tau siv PON los txuag cov nqi fiber. PON nyuam qhuav tau nyiam kev saib xyuas vim nws tus nqi qis thiab kev ua tau zoo. Hauv tsab xov xwm no, peb yuav qhia txog ABC ntawm PON, uas feem ntau cuam tshuam nrog cov khoom yooj yim thiab cov thev naus laus zis cuam tshuam ntawm OLT, ONT, ONU thiab ODN.
Ua ntej, nws yog qhov tsim nyog los qhia luv luv txog PON. Sib piv rau AON, ntau tus neeg siv khoom txuas nrog ib lub transceiver los ntawm ib ceg ntoo ntawm cov fiber ntau optical thiab passive splitter / combiner units, uas ua haujlwm tag nrho hauv thaj chaw optical, thiab tsis muaj lub zog muab hluav taws xob hauv PON. Tam sim no muaj ob lub qauv PON tseem ceeb: Gigabit Passive Optical Network (GPON) thiab Ethernet Passive Optical Network (EPON). Txawm li cas los xij, tsis hais hom PON twg, lawv txhua tus muaj tib lub topology yooj yim. Nws lub kaw lus feem ntau muaj lub davhlau ya nyob twg optical kab (OLT) hauv chaw ua haujlwm hauv paus ntawm tus neeg muab kev pabcuam thiab ntau lub chaw ua haujlwm optical network (ONU) lossis optical network terminals (ONT) ze rau tus neeg siv kawg ua optical splitters.
Lub Rooj Sib Tham Txog Kab Optical (OLT)
OLT sib koom ua ke L2/L3 switching khoom siv hauv G/EPON system. Feem ntau, OLT khoom siv suav nrog khib, CSM (tswj thiab hloov module), ELM (EPON txuas module, PON daim npav), kev tiv thaiv redundant -48V DC fais fab mov module lossis 110/220V AC fais fab mov module thiab kiv cua. Hauv cov khoom no, PON daim npav thiab fais fab mov txhawb nqa kev sib pauv kub, thaum lwm cov modules tau tsim rau hauv. Lub luag haujlwm tseem ceeb ntawm OLT yog los tswj kev xa cov ntaub ntawv ob txoj kev ntawm ODN nyob hauv chaw ua haujlwm hauv nruab nrab. Qhov deb tshaj plaws uas txhawb nqa los ntawm ODN kis yog 20 km. OLT muaj ob txoj kev taw qhia: upstream (tau txais ntau hom ntaub ntawv thiab suab tsheb khiav los ntawm cov neeg siv) thiab downstream (tau txais cov ntaub ntawv, suab thiab video tsheb khiav los ntawm metro lossis cov tes hauj lwm ntev, thiab xa mus rau txhua ONTs ntawm lub network Module) ODN.
Chav Optical Network (ONU)
ONU hloov cov teeb liab pom kev uas xa los ntawm cov fibers pom kev mus rau hauv cov teeb liab hluav taws xob. Cov teeb liab hluav taws xob no ces raug xa mus rau txhua tus neeg siv. Feem ntau, muaj qhov deb lossis lwm qhov kev nkag mus rau hauv network ntawm ONU thiab lub tsev ntawm tus neeg siv kawg. Tsis tas li ntawd, ONU tuaj yeem xa, sib sau ua ke thiab npaj ntau hom ntaub ntawv los ntawm cov neeg siv khoom, thiab xa nws mus rau OLT. Kev npaj yog cov txheej txheem ntawm kev ua kom zoo dua thiab rov npaj cov ntaub ntawv, yog li nws tuaj yeem xa tau zoo dua. OLT txhawb nqa kev faib bandwidth, uas tso cai rau cov ntaub ntawv kom raug xa mus rau OLT, uas feem ntau yog qhov xwm txheej tam sim ntawd los ntawm cov neeg siv khoom. ONU tuaj yeem txuas nrog ntau txoj hauv kev thiab hom cable, xws li cov xov tooj liab twisted pair, coaxial cable, optical fiber lossis Wi-Fi.
Chaw Nres Tsheb Optical Network (ONT)
Qhov tseeb, ONT yeej zoo ib yam li ONU. ONT yog ib lo lus ITU-T, thiab ONU yog ib lo lus IEEE. Lawv txhua tus xa mus rau cov khoom siv sab hauv GEPON system. Tab sis qhov tseeb, raws li qhov chaw ntawm ONT thiab ONU, muaj qee qhov sib txawv ntawm lawv. ONT feem ntau nyob ntawm cov neeg siv khoom thaj chaw.
Kev Sib Txuas Lus Txog Kev Faib Khoom Siv Optical (ODN)
ODN yog ib feem tseem ceeb ntawm lub kaw lus PON, uas muab cov khoom siv xa hluav taws xob rau kev sib txuas ntawm ONU thiab OLT. Qhov ncav cuag ntau yog 20 kilometers lossis ntau dua. Hauv ODN, cov xov hluav taws xob, cov khoom sib txuas hluav taws xob, cov khoom sib cais hluav taws xob passive thiab cov khoom pabcuam koom tes ua ke. ODN muaj tsib ntu, uas yog cov khoom siv fiber ntau, qhov chaw faib hluav taws xob, cov khoom faib hluav taws xob, qhov chaw nkag mus rau qhov muag thiab cov khoom siv fiber ntau. Cov khoom siv fiber ntau pib los ntawm lub thav duab faib hluav taws xob (ODF) hauv chav ua haujlwm hauv chaw ua haujlwm (CO) thiab xaus rau ntawm qhov chaw faib teeb rau kev them nqi ntev. Cov khoom faib hluav taws xob los ntawm qhov chaw faib hluav taws xob mus rau qhov chaw nkag mus rau qhov muag faib cov khoom siv fiber ntau mus rau thaj chaw ib sab ntawm nws. Kev qhia txog cov khoom siv fiber ntau txuas qhov chaw nkag mus rau qhov chaw davhlau ya nyob twg (ONT) kom cov khoom siv fiber ntau nkag mus rau hauv tsev ntawm tus neeg siv. Tsis tas li ntawd, ODN yog txoj hauv kev tseem ceeb rau kev xa cov ntaub ntawv PON, thiab nws qhov zoo cuam tshuam ncaj qha rau kev ua tau zoo, kev ntseeg siab thiab kev nthuav dav ntawm PON system.
Lub sijhawm tshaj tawm: Lub Kaum Ob Hlis-31-2021