Inethiwekhi ye-EPON isebenzisa indlela ye-FTTB ukwenza inethiwekhi, futhi amayunithi ayo enethiwekhi ayisisekeloOLTfuthiI-ONU. IOLTihlinzeka ngamachweba amaningi e-PON ukuze kuxhunywe imishini yehhovisi elimaphakathiI-ONUokokusebenza;I-ONUiyisisetshenziswa somsebenzisi esihlinzeka ngedatha ehambisanayo nezixhumi zezwi ukuze kuqhamuke ukufinyelela kwesevisi yomsebenzisi.Ukwenziwa kokufinyelela ezinsizeni ezihlukene ikakhulukazi ukusebenzisa amathegi ahlukene e-VLAN kubasebenzisi abahlukene kanye nezinsiza ezahlukene ukuze kudluliselwe ngokusobala kuseva yokufinyelela yesevisi ehambisanayo, nokuthumela amathegi e-VLAN ahambelanayo kunethiwekhi yenkampani ye-IP ukuze adluliselwe.
1.Isingeniso ku-EPON Network
I-EPON (i-Ethernet Passive Optical Network) iwubuchwepheshe benethiwekhi obusafufusa be-fiber optical, obusebenzisa isakhiwo se-point-to-multipoint, imodi yokudlulisa i-fiber optical passive, esekelwe kupulatifomu ye-Ethernet enesivinini esikhulu kanye ne-TDM yesigaba sokuhlukanisa isikhathi se-MAC (MediaAccessControl) imodi yokulawula ukufinyelela kwemidiya. , Nikeza ubuchwepheshe bokufinyelela ku-broadband ezinhlobonhlobo zezinsizakalo ezihlanganisiwe.Lokho okubizwa ngokuthi "i-passive" kusho ukuthi i-ODN ayiqukethe noma yiziphi izisetshenziswa zikagesi ezisebenzayo kanye nempahla yamandla, futhi yakhiwe ngokuphelele amadivaysi angenzi lutho njengama-optical splitters (Splitter). Isebenzisa ubuchwepheshe be-PON kungqimba olubonakalayo, iphrothokholi ye-Ethernet kungqimba yesixhumanisi, futhi isebenzisa i-PON topology ukuzuza ukufinyelela kwe-Ethernet. Ngakho-ke, ihlanganisa izinzuzo zobuchwepheshe be-PON nobuchwepheshe be-Ethernet: izindleko eziphansi, umkhawulokudonsa ophezulu, ukuqina okuqinile, ukuhlelwa kabusha kwesevisi okuguquguqukayo nokushesha, ukuhambisana ne-Ethernet ekhona, ukuphathwa okulula, njalonjalo.
I-EPON ingabona ukuhlanganiswa kwezwi, idatha, ividiyo, namasevisi eselula. Isistimu ye-EPON yakhiwe ikakhulukaziOLT(itheminali ye-optical line),I-ONU(iyunithi yenethiwekhi ye-optical), i-ONT (itheminali yenethiwekhi yokubona) kanye ne-ODN (inethiwekhi yokusabalalisa ebonakalayo), Isezingeni lenethiwekhi yokufinyelela yenethiwekhi futhi ifaneleka kakhulu ukufinyelela kwe-fiber optical kumasevisi e-broadband.
Imishini yenethiwekhi esebenzayo ihlanganisa imishini yokubeka ehhovisi emaphakathi (OLT) kanye neyunithi yenethiwekhi yokubona (I-ONU). Iyunithi yenethiwekhi ye-optical (I-ONU) inikeza abasebenzisi ukuxhumana phakathi kwedatha, ividiyo, namanethiwekhi ocingo kanye ne-PON. Indima yokuqala yeI-ONUiwukwamukela isignali yokubona bese uyiguqulela kufomethi edingwa umsebenzisi (i-Ethernet, ukusakaza kwe-IP, ucingo, i-T1/E1, njll.).OLTokokusebenza kuxhunywe kunethiwekhi ye-IP core nge-fiber optical. Ukwethulwa kwenethiwekhi ye-optical access inendawo efinyelela ku-20km, okuqinisekisa ukuthiOLTingathuthukiswa iye endaweni yendabuko yokuhlangana yedolobha elikhulu kusukela esigabeni sokuqala sokwakhiwa kwenethiwekhi yokufinyelela optical, ngaleyo ndlela kube lula ukwakheka kwenethiwekhi yesendlalelo sokuhlangana kwenethiwekhi nokulondoloza inani lamahhovisi okugcina. Ngaphezu kwalokho, izici zomthamo omkhulu wenethiwekhi yokufinyelela okubonakalayo, umkhawulokudonsa ophezulu wokufinyelela, ukwethembeka okuphezulu, namandla okusekelwa kwezinga le-QoS lezinsizakalo eziningi nakho kwenze ukuvela kwenethiwekhi yokufinyelela kufinyelele endaweni yesikhulumi esihlangene, esihlanganisiwe, nesisebenzayo saba ngokoqobo.
2.Izimiso Eziyisisekelo ze-EPON Network
Uhlelo lwe-EPON lusebenzisa ubuchwepheshe be-WDM ukuze kuzuzwe ukudluliswa kwe-bidirectional ye-fiber eyodwa, kusetshenziswa i-1310nm ekhuphuka nomfula kanye no-1490nm wamaza owela phansi ukuze idlulise idatha nezwi, futhi izinsiza ze-CATV zisebenzisa ubude begagasi obungu-1550nm ukuthwala.OLTibekwe ehhovisi elikhulu ukuze ihlukanise futhi ilawule ukuxhunywa kwesiteshi, futhi inomsebenzi wokuqapha, wokuphatha nowokugcina ngesikhathi sangempela. II-ONUibekwe ohlangothini lomsebenzisi, futhi iOLTkanye neI-ONUaxhunywe ngendlela engu-1:16/1:32 ngenethiwekhi yokusabalalisa engabonakali.
Ukuze uhlukanise amasignali kubasebenzisi abaningi ku-fiber efanayo, izindlela ezimbili ezilandelayo zokuphindaphinda zingasetshenziswa.
1) Ukusakazwa kwedatha okwehlayo kusebenzisa ubuchwepheshe bokusakaza.
Ku-EPON, inqubo yokudluliswa kwedatha eya phansi kusukaOLTkokuningiAma-ONUithunyelwa ngokusakazwa kwedatha. Idatha isakazwa phansi kusukela ku-OLTkokuningiAma-ONUngendlela yamaphakethe anobude obuguquguqukayo.Iphakethe ngalinye lolwazi line-I-EPONunhlokweni wephakethe, okhomba ngokukhethekile ukuthi iphakethe lolwazi lithunyelwa kuloI-ONU-1,I-ONU-2 nomaI-ONU-3. Ingaphinde ikhonjwe njengephakethe lokusakaza elithunyelwa kubo bonkeAma-ONUnoma kokuthileI-ONUiqembu (iphakethe lokusakaza okuningi). Lapho idatha ifika ku-I-ONU,iI-ONUyamukela futhi ihlonze amaphakethe olwazi athunyelwe kuwo ngokufaniswa kwekheli, futhi ilahle amaphakethe olwazi athunyelwe kwamanyeAma-ONU. I-LLID ehlukile inikezwa ngemuva kwe-I-ONUibhalisiwe; iOLTuqhathanisa uhlu lokubhalisa lwe-LLID lapho uthola idatha, futhi laphoI-ONUithola idatha, ithola kuphela ozimele noma ozimele abasakazayo abafana ne-LLID yayo.
2) Ukugeleza kwedatha okukhuphukayo kusebenzisa ubuchwepheshe be-TDMA.
IOLTuqhathanisa uhlu lokubhalisa lwe-LLID ngaphambi kokuthola idatha; ngamunyeI-ONUithumela uhlaka lwedatha esikhaleni sesikhathi esabelwe izinto zokusebenza zehhovisi elimaphakathiOLT; isikhathi esabiwe (ngokusebenzisa ubuchwepheshe obuhlukahlukene) sinxephezela igebe lebanga phakathi kwesinyeI-ONUfuthi igwema ngayinyeI-ONUUkungqubuzana phakathi.