1 Intangiriro
Hamwe niterambere ryihuse ryikoranabuhanga ryogukoresha umurongo mugari, tekinoroji zitandukanye zigaragara zagutse nyuma yimvura. Nyuma yubuhanga bwa PON nubuhanga bwa DSL nubuhanga bwa kabili, ubundi buryo bwiza bwo kugera, PON irashobora gutanga serivisi nziza cyangwa serivisi za FTTH. EPON ni ubwoko bushya bwa fibre igera kumurongo wa tekinoroji, ukoresheje ingingo kumiterere yibice byinshi, itumanaho ridafite isoko, ritanga serivise zitandukanye za Ethernet. Ikoresha topologiya ya PON kugirango ishyire mubikorwa Ethernet, kandi tekinoroji ya PON ikoreshwa murwego rwumubiri murwego rwumubiri. Kubwibyo, ihuza ibyiza bya tekinoroji ya PON na tekinoroji ya Ethernet: igiciro gito; umurongo mwinshi; imbaraga zikomeye, kuvugurura serivisi byihuse kandi byihuse; guhuza na Ethernet ihari; gucunga neza, nibindi. Ikizamini cya EPON kiratandukanye cyane nibikoresho gakondo bya Ethernet. Iyi ngingo yibanze ku buhanga bwo gupima EPON.
2 Intangiriro ya tekinoroji ya EPON hamwe nikibazo cyo kugerageza
UwitekaEPONsisitemu igizwe nubwinshi bwibikoresho bya optique, itara ryoroheje (OLT), hamwe na kimwe cyangwa byinshi (reba Ishusho 1). Mu cyerekezo cyo kumanura, ibimenyetso byoherejwe na OLT byerekanwa kuri ONU zose. Mu cyerekezo cyo hejuru, tekinoroji ya TDMA ikoreshwa, kandi amakuru yo hejuru ya ONU menshi akora TDM amakuru kuri OLT. 802.3AH Hindura imiterere yikadiri ya Ethernet, ongera usobanure igice cyabanjirije, ongeraho igihe cyagenwe nibiranga amahuza (LLID). LLID igaragaza buri ONU ya sisitemu ya PON ikanagaragaza LLID mugihe cyo kuvumbura.
3 Ikoranabuhanga ryingenzi muri sisitemu ya PON
Muri sisitemu ya EPON, intera igaragara hagati ya buri ONU na OLT murwego rwo hejuru rwohereza amakuru ntabwo aringana. Mubisanzwe, sisitemu ya EPON iteganya ko intera ndende kuva ONU kugeza OLT ari 20km, naho intera ngufi ni 0km. Itandukaniro ryintera ritera gutinda gutandukana hagati ya 0 na 200 natwe. Niba nta cyuho gihagije cyo kwigunga, ibimenyetso biva muri ONU zitandukanye birashobora kugera kumpera ya OLT icyarimwe, bigatera amakimbirane yibimenyetso byo hejuru. Amakimbirane arashobora gutera umubare munini wamakosa no gutakaza igihombo, nibindi, bigatuma sisitemu idakora neza. Ukoresheje uburyo buringaniye, banza upime intera igaragara, hanyuma uhindure ONU zose kurugero rumwe rwumvikana na OLT, hanyuma ukore uburyo bwa TDMA kugirango wirinde amakimbirane. Kugeza ubu uburyo bwakoreshejwe burimo gukwirakwiza-gukwirakwiza urutonde, hanze ya bande no muri bande idirishya rifungura. Kurugero, ukoresheje uburyo-buringaniye buringaniye, banza upime ibimenyetso bya loop itinda kuva kuri buri ONU kugeza kuri OLT, hanyuma ushiremo gutinda kuringaniza gutinda agaciro ka Td kuri buri ONU, kugirango loop itinde kuri ONU zose nyuma yo gushyiramo Td ishobora kuboneka Igihe (byitwa kuringaniza loop gutinda agaciro Tequ) birangana, kandi ibisubizo bisa no kwimura buri ONU kumurongo umwe wumvikana nka OLT, hanyuma wohereze ikadiri neza ukurikije tekinoroji ya TDMA nta kugongana.
OLT isanga ONU muri sisitemu ya PON buri gihe yohereza ubutumwa bwa Gate MPCP. Nyuma yuko ONU itiyandikishije yakiriye ubutumwa bw Irembo, izategereza igihe cyateganijwe (kugirango wirinde icyarimwe kwiyandikisha kuri ONU nyinshi), hanyuma wohereze ubutumwa bwanditse kuri OLT. Nyuma yo kwiyandikisha neza, OLT igenera LLID kuri ONU.
Nyuma yuko ONU yiyandikishije hamwe na OLT, Ethernet OAM kuri ONU itangira inzira yo kuvumbura igashyiraho isano na OLT. Ethernet OAM ikoreshwa mugutahura amakosa ya kure kumurongo wa ONU / OLT, gukurura kure, no kumenya ubuziranenge bwihuza. Nyamara, Ethernet OAM itanga inkunga kubisanzwe OAM PDUs, ibice byamakuru, na raporo zigihe. Benshi mubakora ONU / OLT bakoresha umugereka wa OAM kugirango bashireho imirimo yihariye ya ONU. Porogaramu isanzwe ni ukugenzura umurongo wabakoresha ba nyuma ukoresheje uburyo bwagutse bwagutse bwa moderi muri ONU. Iyi porogaramu itari isanzwe nurufunguzo rwikizamini kandi iba inzitizi yimikoranire hagati ya ONU na OLT.
Iyo OLT ifite traffic yohereza ONU, izatwara amakuru ya LLID yerekanwe ONU mumodoka. Bitewe no gutangaza ibiranga PON, amakuru yoherejwe na OLT azashyikirizwa ONU zose. By'umwihariko, ibihe aho urujya n'uruza rwinshi rwohereza amashusho ya videwo bigomba gusuzumwa. Bitewe no gutangaza ibiranga sisitemu ya EPON, mugihe umukoresha yihitiyemo porogaramu ya videwo, izashyikirizwa abakoresha bose, itwara umurongo mwinshi wo hasi. OLT mubisanzwe ishyigikira IGMP Snooping. Irashobora gukurikirana IGMP Kwinjira Gusaba ubutumwa no kohereza amakuru menshi kubakoresha bijyanye nitsinda aho gutangaza kubakoresha bose, bityo kugabanya traffic.
ONU imwe yonyine irashobora kohereza traffic mugihe runaka. ONU ifite imirongo myinshi yibanze (buri murongo uhuye nurwego rwa QoS. ONU yohereza ubutumwa bwa OLT kugirango isabe amahirwe yo kohereza, isobanura uko buri murongo uhagaze. OLT yohereza ubutumwa bw Irembo kuri ONU kubwira ONU igihe cyo gutangira gukurikira kuri OLT Igomba kuba ishobora gucunga umurongo wa interineti wa ONUs zose, kandi igomba guha umwanya urwego rwohereza. Ukurikije ibyihutirwa byumurongo, kuringaniza ibyifuzo bya ONU nyinshi ushoboye gucunga umurongo wibisabwa bya ONU zose kandi ugabanye imbaraga zo hejuru (ni ukuvuga DBA algorithm).