1.1 I-Passive Optical splitter
I-Passive Optical splitter iyingxenye ebalulekile yenethiwekhi ye-PON.Umsebenzi we-passive optical splitter ukuhlukanisa amandla okubona esignali eyodwa yokubona okokufaka kokuphumayo okuningi.Ngokuvamile, isihlukanisi sizuza ukuhlukaniswa okukhanyayo kusuka ku-1:2 kuya ku-1:32 noma ngisho no-1:64.Isici se-passive optical splitter ukuthi ayidingi ukunikezwa kwamandla futhi inokuguquguquka okuqinile kwemvelo.Njengoba isiteshi esikhuphuka nomfula i-EPON sihlukanisa isikhathi siphindaphindwa yibo bonkeI-ONUs, i-ONU ngayinye ingathumela idatha ngaphakathi kwewindi lesikhathi elishiwo.Ngakho-ke, isiteshi esikhuphuka nomfula i-EPON sidlulisa amasiginali okuqhuma, okudinga ukusetshenziswa kwamadivayisi abonakalayo asekela izimpawu zokuqhuma kuma-ONU nama-OLT.
Izihlukanisi ze-Passive Optical kumanethiwekhi we-PON ngokuvamile zihlukaniswa zibe izinhlobo ezimbili: isihlukanisi se-fusion taper esivamile kanye nesihlukanisi se-waveguide sokukhanya esisanda kuvela.
1.2 I-Physical topology
Inethiwekhi ye-EPON yamukela isakhiwo se-point-to-multipoint topology esikhundleni se-point-to-point structure, esisindisa kakhulu inani le-optical fiber kanye nezindleko zokuphatha.I-PONOLTokokusebenza kunciphisa inani lamalaser adingwa ihhovisi elimaphakathi, futhi i-OLT yabelwa abasebenzisi abaningi be-ONU.Ngaphezu kwalokho, i-EPON isebenzisa ubuchwepheshe be-Ethernet nozimele be-Ethernet abajwayelekile ukuze baphathe isevisi yamanje evamile—isevisi ye-IP ngaphandle kwanoma yikuphi ukuguqulwa.
1.3 Ukuvumelanisa okuqhume kwesendlalelo esibonakalayo se-EPON
Ukuze unciphise izindleko ze-ONU, ubuchwepheshe obubalulekile be-I-EPONungqimba olungokwenyama lugxile ku-OLT, okuhlanganisa: ukuvumelanisa okusheshayo kwezimpawu eziqhumayo, ukuvumelanisa kwenethiwekhi, ukulawulwa kwamandla amamojula we-transceiver optical, nokwamukela okuguquguqukayo.
Njengoba isignali etholwe yi-OLT iyisiginali yokuqhuma ye-ONU ngayinye, i-OLT kufanele ikwazi ukuzuza ukuvumelanisa kwesigaba ngesikhathi esifushane, bese ithola idatha.Ukwengeza, ngenxa yokuthi isiteshi se-uplink samukela imodi ye-TDMA, kanye nobuchwepheshe besinxephezelo sokubambezeleka kokudlulisa i-fiber engu-20km bubona ukuvumelanisa kweskhathi senethiwekhi yonke, amaphakethe wedatha afika ngesikhathi esinqunywa i-algorithm ye-OBA.Ngaphezu kwalokho, ngenxa yamabanga ahlukene e-ONU ngayinye ukusuka ku-OLT, kumojula yokwamukela ye-OLT, amandla ezikhala zesikhathi ezihlukene ahlukile.Kuzinhlelo zokusebenza ze-DBA, ngisho namandla e-slot yesikhathi esifanayo ahlukile, okubizwa ngokuthi umphumela oseduze-kude.Ngakho-ke, i-OLT kufanele ikwazi ukulungisa ngokushesha amaphuzu ayo ezinqumo "0" kanye "no-"1".Ukuze kuxazululwe "umphumela oseduze", uhlelo lokulawula amandla luye lwahlongozwa, futhi i-OLT yazisa i-ONU ngezinga lamandla okudlulisa ngokusebenzisa amaphakethe okuphatha nokuphatha (OAM) ngemva kokulinganisa.Ngenxa yokuthi lolu hlelo luzokhuphula izindleko ze-ONU kanye nobunkimbinkimbi bephrothokholi yesendlalelo somzimba, futhi lukhawulele ukusebenza komugqa wokudlulisela ezingeni le-ONU elikude kakhulu ne-OLT, alukamukelwa iqembu elisebenzayo le-EFM.