PON: Kumvetsetsa OLT, ONU, ONT ndi ODN

M'zaka zaposachedwa, fiber to the home (FTTH) yayamba kuyamikiridwa ndi makampani opanga mauthenga padziko lonse lapansi, ndipo luso lothandizira likukula mofulumira.Pali mitundu iwiri yofunika dongosolo FTTH burodibandi malumikizidwe.Izi ndi Active Optical Network (AON) ndi Passive Optical Network (PON).Pakadali pano, ma FTTH ambiri omwe amatumizidwa pakukonzekera ndi kutumiza agwiritsa ntchito PON kupulumutsa mtengo wa fiber.PON yakopa chidwi posachedwa chifukwa cha mtengo wake wotsika komanso magwiridwe antchito apamwamba.M'nkhaniyi, tikuwonetsani ABC ya PON, yomwe imakhudza makamaka zigawo zikuluzikulu ndi matekinoloje okhudzana ndi OLT, ONT, ONU ndi ODN.

Choyamba, ndikofunikira kufotokozera mwachidule PON.Mosiyana ndi AON, makasitomala ambiri amalumikizidwa ndi transceiver imodzi kudzera mumtengo wa nthambi ya optical fiber ndi passive splitter / combiner units, zomwe zimagwira ntchito zonse mu optical domain, ndipo palibe magetsi mu PON.Pakali pano pali mfundo ziwiri zazikulu za PON: Gigabit Passive Optical Network (GPON) ndi Ethernet Passive Optical Network (EPON).Komabe, ziribe kanthu mtundu wa PON, onse ali ndi topology yofanana.Dongosolo lake nthawi zambiri limakhala ndi optical line terminal (OLT) muofesi yapakati ya othandizira ndi mayunitsi ambiri opangira ma netiweki (ONU) kapena optical network terminals (ONT) pafupi ndi wogwiritsa ntchito ngati optical splitters.

Optical Line Pokwerera (OLT)

OLT imaphatikiza zida zosinthira L2/L3 mu dongosolo la G/EPON.Nthawi zambiri, zida za OLT zimaphatikizapo rack, CSM (control and switching module), ELM (EPON link module, PON khadi), chitetezo chowonjezera -48V DC gawo lamagetsi kapena gawo lamagetsi la 110/220V AC ndi fan.M'zigawozi, khadi la PON ndi mphamvu zothandizira kusinthanitsa kutentha, pamene ma modules ena amamangidwa.Mtunda waukulu wothandizidwa ndi kufalitsa kwa ODN ndi 20 km.OLT ili ndi mayendedwe awiri oyandama: kumtunda (kupeza mitundu yosiyanasiyana ya data ndi kuchuluka kwa mawu kuchokera kwa ogwiritsa ntchito) ndi kutsika (kulandira deta, mawu ndi makanema apamtunda kuchokera kumayendedwe a metro kapena mtunda wautali, ndikutumiza ku ma ONT onse pa netiweki Module) ODN.

Optical Network Unit (ONU)

ONU imatembenuza ma siginecha owoneka omwe amafalitsidwa kudzera mu ulusi wa kuwala kukhala ma siginecha amagetsi.Zizindikiro zamagetsizi zimatumizidwa kwa wogwiritsa ntchito aliyense.Nthawi zambiri, pamakhala mtunda kapena maukonde ena ofikira pakati pa ONU ndi nyumba ya wogwiritsa ntchito.Kuonjezera apo, ONU ikhoza kutumiza, kusonkhanitsa ndi kukonza mitundu yosiyanasiyana ya deta kuchokera kwa makasitomala, ndikutumiza kumtunda kwa OLT.Kukonzekera ndi njira yokonzekera ndi kukonzanso mtsinje wa deta, kotero kuti ukhoza kuperekedwa bwino kwambiri.OLT imathandizira kugawa kwa bandwidth, zomwe zimalola kuti deta isamutsidwe bwino ku OLT, yomwe nthawi zambiri imakhala mwadzidzidzi kuchokera kwa kasitomala.ONU ikhoza kulumikizidwa ndi njira zosiyanasiyana ndi mitundu ya chingwe, monga waya wopindika wamkuwa, chingwe cha coaxial, fiber optical kapena Wi-Fi.

Optical Network Terminal (ONT)

M'malo mwake, ONT ndiyofanana ndi ONU.ONT ndi mawu a ITU-T, ndipo ONU ndi mawu a IEEE.Onse amatchula zida za mbali za ogwiritsa ntchito mu dongosolo la GEPON.Koma kwenikweni, malinga ndi malo a ONT ndi ONU, pali kusiyana pakati pawo.ONT nthawi zambiri imakhala pamalo a kasitomala.

Optical Distribution Network (ODN)

ODN ndi gawo lofunikira la dongosolo la PON, lomwe limapereka njira yolumikizira kuwala kwa kulumikizana kwakuthupi pakati pa ONU ndi OLT.Mtunda wofikirako ndi makilomita 20 kapena kupitirira apo.Mu ODN, zingwe za kuwala, zolumikizira zowoneka bwino, zogawanitsa zapang'onopang'ono ndi zida zothandizira zimagwirizana.ODN makamaka ili ndi magawo asanu, omwe ndi fiber feeder, optical distribution point, distribution fiber, optical access point ndi fiber yomwe ikubwera.Ulusi wa feeder umayambira pa optical distribution frame (ODF) muchipinda chapakati pa ofesi (CO) cholumikizirana ndi kukathera pamalo opangira magetsi kuti azitha kuphimba mtunda wautali.Chingwe chogawa kuchokera kumalo operekera kuwala kupita kumalo opangira kuwala kumagawira ulusi wa kuwala kumalo omwe ali pafupi nawo.Kuyambitsidwa kwa fiber optical kumagwirizanitsa malo opita kumtunda (ONT) kotero kuti kuwala kwa kuwala kumalowa m'nyumba ya wogwiritsa ntchito.Kuphatikiza apo, ODN ndi njira yofunikira kwambiri yotumizira ma data a PON, ndipo mtundu wake umakhudza mwachindunji magwiridwe antchito, kudalirika komanso scalability wa dongosolo la PON.