1. EPON network sumo
EPON(Ethernet Passive Optical Network) inobuda optical fiber access network tekinoroji, iyo inotora point-to-multipoint chimiro, passive optical fiber transmission mode, yakavakirwa pakakwirira-speed Ethernet papuratifomu uye TDM nguva kupatsanura MAC (MediaAccessControl) midhiya yekudzora nzira, Ipa akasiyana siyana eBroadband kuwana matekinoroji emasevhisi akabatanidzwa.Izvo zvinonzi "passive" zvinoreva kuti ODN haina chero zvigadzirwa zvemagetsi zvinoshanda uye magetsi emagetsi, uye zvese zvine zvigadziriso zvakadai semagetsi emagetsi (Splitter).Inoshandisa tekinoroji yePON pachikamu chemuviri, Ethernet protocol padanho rekubatanidza, uye inoshandisa iyo PON topology kuwana Ethernet yekuwana.Naizvozvo, inosanganisa zvakanakira zvePON tekinoroji uye Ethernet tekinoroji: mutengo wakaderera, wakakwira bandwidth, yakasimba scalability, inochinjika uye nekukurumidza sevhisi kurongazve, kuenderana neiyo iripo Ethernet, nyore manejimendi, zvichingodaro.
EPON inogona kuona kubatanidzwa kwezwi, data, vhidhiyo, uye nharembozha.Iyo EPON system inonyanya kuumbwa neOLT (optical line terminal),ONU(optical network unit), ONT (optical network terminal) uye ODN (optical distribution network).Iyo iri padanho retiweki retiweki uye inonyanya kukodzera optical fiber yekubatanidza yebroadband masevhisi.Into.
Active network midziyo inosanganisira yepakati hofisi rack michina (OLT) uye optical network unit (ONU).Iyo optical network unit (ONU) inopa vashandisi chimiro pakati pe data, vhidhiyo, uye nhare network nePON.Basa rekutanga reONU nderekugamuchira chiratidzo chemaziso uye wozochishandura kuva chimiro chinodiwa nemushandisi (Ethernet, IP nhepfenyuro, foni, T1 / E1, nezvimwewo).OLT midziyo yakabatana neiyo IP core network kuburikidza neoptical fiber.Iko kuunzwa kweiyo optical access network ine kufukidzwa kunosvika 20km, iyo inovimbisa kutiOLTinogona kukwidziridzwa kune yechinyakare metropolitan convergence node kubva padanho rekutanga reiyo optical access network yekuvaka, nekudaro kurerutsa iyo network chimiro cheiyo convergence layer yekuwana network uye kuchengetedza Nhamba yekupera mahofisi.Pamusoro pezvo, hunhu hweiyo optical access network yakakura, yakakwirira yekupinda bandwidth, yakakwirira kuvimbika, uye akawanda-sevhisi QoS level tsigiro yaitawo shanduko yetiweki yekuwana kune yakabatana, yakabatanidzwa, uye inoshanda mutakuri chikuva.
2. Basic Principles yeEPON Network
Iyo EPON sisitimu inoshandisa tekinoroji yeWDM kuona kutapurirana-fiber bidirectional, uchishandisa kumusoro 1310nm nekudzika 1490nm wavelengths kufambisa data nezwi, uye masevhisi eCATV anoshandisa 1550nm wavelength kutakura.Iyo OLT inoiswa muhofisi yepakati kuti igovere uye kudzora kubatana kwechiteshi, uye ine chaiyo-nguva yekutarisa, manejimendi uye kugadzirisa mabasa.Iyo ONU inoiswa kudivi remushandisi, uye OLT neONU zvakabatanidzwa nenzira ye1:16/1:32 kuburikidza neine passive optical distribution network.Kuti uparadzanise zviratidzo kubva kune vakawanda vashandisi pane imwechete fiber, nzira mbiri dzinotevera dze multiplexing dzinogona kushandiswa.
(1) Iyo yakadzika data rwizi inotora tekinoroji yekutepfenyura.MuEPON, maitiro ekufambisa data kubva kuOLT kuenda kune akawanda ONU anotumirwa nekutepfenyura data.Data inotepfenyurwa yakadzika kubva kuOLT kuenda kune akawanda maONU nenzira yemapaketi eruzivo rwekusiyana-urefu.Packet yega yega yeruzivo ine musoro weEPON wepacket, unotaridza zvakasiyana kuti packet yeruzivo yakatumirwa kuONU-1, ONU-2 kana ONU-3.Inogona zvakare kumakwa sepaketi yeruzivo rwenhepfenyuro inotumirwa kune ese maONU kana kune chaiyo ONU boka (multicast information packet).Kana iyo data yasvika paONU, ONU inogamuchira uye inoziva mapepa emashoko anotumirwa kwairi kuburikidza nekero yekuenzanisa, uye inorasa mapepa emashoko anotumirwa kune mamwe maONU.LLID yakasarudzika inopihwa mushure mekunge ONU yanyoreswa;iyo OLT inoenzanisa iyo LLID yekunyoreswa runyorwa kana ichigamuchira data, uye kana ONU yagamuchira data, inongogashira mafuremu kana kutepfenyura mafuremu anofanana neLLID yayo.
(2) Kukwidza kwedata kuyerera kunotora tekinoroji yeTDMA.Iyo OLT inoenzanisa iyo LLID yekunyoresa runyorwa isati yagamuchira data;ONU yega yega inotumira data furemu munguva yenguva yakagoverwa zvakafanana nepakati hofisi midziyo OLT;iyo yakagoverwa nguva yakarongedzerwa (kuburikidza nerange tekinoroji) inotsiva gaka riri kure neONU yega yega uye inodzivirira yega yega ONU Collision pakati.
