1. Isingeniso senethiwekhi ye-EPON
I-EPON(I-Ethernet Passive Optical Network) ubuchwepheshe benethiwekhi obusafufusa be-fiber optical, obusebenzisa isakhiwo se-point-to-multipoint, imodi yokudlulisa i-fiber optical passive, esekelwe ku-high-speed Ethernet platform kanye ne-TDM time division MAC (MediaAccessControl) imodi yokulawula ukufinyelela kwemidiya, Nikeza ngezinhlobonhlobo zobuchwepheshe bokufinyelela ku-broadband ukuze uthole izinsiza ezihlanganisiwe. Okubizwa ngokuthi "i-passive" kusho ukuthi i-ODN ayinazo izisetshenziswa zikagesi ezisebenzayo kanye nempahla yamandla, futhi konke kuqukethe amadivaysi angenayo njengama-optical splitters (Splitter). Isebenzisa ubuchwepheshe be-PON kungqimba ebonakalayo, iphrothokholi ye-Ethernet kungqimba yesixhumanisi, futhi isebenzisa i-PON topology ukuze ifinyelele 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 ye-optical) kanye ne-ODN (inethiwekhi yokusabalalisa optical). Isezingeni lenethiwekhi yokufinyelela yenethiwekhi futhi ilungele kakhulu ukuxhumana kwe-fiber optical yezinsizakalo ze-broadband. Ingene.
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 ifinyelela ku-20km, okuqinisekisa ukuthiOLTingathuthukiswa iye endaweni yendabuko ye-metropolitan convergence node kusukela esigabeni sokuqala sokwakhiwa kwenethiwekhi yokufinyelela optical, ngaleyo ndlela kube lula ukwakheka kwenethiwekhi ye-convergence layer yenethiwekhi yokufinyelela kanye nokulondoloza Inombolo yamahhovisi okugcina. Ukwengeza, 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 lubone ukudluliswa kwe-bidirectional ye-fiber eyodwa, kusetshenziswa ubude begagasi obungu-1310nm obukhuphuka nomfula obungu-1490nm obungezansi ukuze budlulise idatha nezwi, futhi izinsiza ze-CATV zisebenzisa ubude beza beza obungu-1550nm ukuze buthwale. IOLTibekwe ehhovisi elimaphakathi ukuze isabalalise futhi ilawule ukuxhunywa kwesiteshi, futhi inemisebenzi yokuqapha, yokuphatha kanye neyokunakekela ngesikhathi sangempela. II-ONUibekwe ohlangothini lomsebenzisi, futhi iOLTkanye neI-ONUaxhunywe ngendlela engu-1:16/1:32 ngenethiwekhi yokusabalalisa engabonakali. Ukuze kuhlukaniswe amasignali kubasebenzisi abaningi ku-fiber efanayo, izindlela ezimbili ezilandelayo zokuphindaphinda zingasetshenziswa.
(1) Ukusakaza kwedatha engezansi kusebenzisa ubuchwepheshe bokusakaza. Ku-EPON, inqubo yokudluliswa kwedatha eya phansi kusuka ku-OLTkokuningiAma-ONUithunyelwa ngokusakazwa kwedatha. Idatha isakazwa phansi kusukela ku-OLTkokuningiAma-ONUngendlela yamaphakethe olwazi anobude obuguquguqukayo. Iphakethe ngalinye lolwazi linombhalo wephakethe we-EPON, okhomba ngokukhethekile ukuthi iphakethe lolwazi lithunyelwa kuI-ONU-1,I-ONU-2 nomaI-ONU-3. Ingase futhi imakwe njengephakethe lolwazi lokusakaza elithunyelwa kubo bonkeAma-ONUnoma kokuthileI-ONUiqembu (iphakethe lolwazi lokusakaza okuningi). Lapho idatha ifika ku-I-ONU, iI-ONUithola futhi ibone amaphakethe olwazi athunyelwe kuyo 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 ebangeni ngalinyeI-ONUfuthi igwema ngayinyeI-ONUUkungqubuzana phakathi.
