Cibiyar sadarwar EPON ta ɗauki hanyar FTTB don samar da hanyar sadarwa, kuma ainihin sashin cibiyar sadarwa shine OLT da ONU. OLT yana ba da wadatattun tashoshin PON don kayan aikin ofisoshin tsakiya don haɗa kayan aikin ONU; ONU kayan aikin mai amfani ne wanda ke ba da bayanai masu dacewa da musaya na murya don gane damar sabis na mai amfani. Don aiwatar da ayyuka daban-daban, masu amfani daban-daban da ayyuka daban-daban ana yiwa alama alama ta VLAN daban-daban don watsawa a zahiri zuwa uwar garken samun damar sabis daidai, kuma ana cire alamun VLAN daidai kuma ana aika su zuwa cibiyar sadarwar IP mai ɗaukar hoto don watsawa.
1. Gabatarwar hanyar sadarwa ta EPON
EPON (Ethernet Passive Optical Network) fasaha ce ta hanyar sadarwa ta hanyar fiber na gani mai tasowa. Yana ɗaukar tsarin ma'ana-zuwa-multipoint, yanayin watsa fiber na gani mai ƙarfi, dangane da babban dandamali na Ethernet mai sauri da Rarraba lokaci na MAC (Mai Kula da Media Access Control) yanayin sarrafa kafofin watsa labarai. , Fasahar hanyar sadarwa ta Broadband wacce ke ba da sabis na haɗin kai iri-iri. Abin da ake kira "passive" yana nufin cewa ODN ba ta ƙunshi kowane na'urorin lantarki masu aiki da kayan wuta ba, kuma ya ƙunshi na'urori marasa amfani kamar masu rarraba gani (Splitter). Yana ɗaukar fasahar PON a cikin Layer na zahiri, yana amfani da ka'idar Ethernet a cikin layin haɗin gwiwa, kuma yana fahimtar damar Ethernet ta amfani da tsarin topology na PON. Sabili da haka, yana haɗuwa da fa'idodin fasahar PON da fasahar Ethernet: ƙananan farashi, babban bandwidth, haɓaka mai ƙarfi, daidaitawa da saurin sake tsara sabis, dacewa tare da Ethernet data kasance, sauƙin gudanarwa da sauransu.
EPON na iya gane haɗin murya, bayanai, bidiyo da sabis na wayar hannu. Tsarin EPON ya ƙunshi OLT (tashar layin gani na gani), ONU (naúrar cibiyar sadarwa ta gani), ONT (tashar hanyar sadarwa ta gani) da ODN (cibiyar rarrabawar gani). shiga.
Kayan aikin cibiyar sadarwa mai aiki sun haɗa da kayan tara kayan ofis na tsakiya (OLT) da naúrar cibiyar sadarwa ta gani (ONU). Raka'o'in hanyar sadarwa na gani (ONUs) suna ba masu amfani da mu'amala tsakanin bayanai, bidiyo da cibiyoyin sadarwar waya da PON. Asalin aikin ONU shine karɓar siginar hanyar gani sannan a canza shi zuwa tsarin da mai amfani ke buƙata (Ethernet, watsa shirye-shiryen IP, tarho, T1/E1, da sauransu). Ana haɗa kayan aikin OLT zuwa cibiyar sadarwar IP ta hanyar filaye masu gani. Gabatar da hanyar sadarwa ta hanyar sadarwa, ɗaukar hoto ya kai 20km, yana tabbatar da cewa za a iya haɓaka OLT zuwa kuɗaɗɗen haɗin gwiwar metro na gargajiya daga matakin farko na ginin hanyar sadarwa na gani, ta haka yana sauƙaƙe tsarin hanyar sadarwa na layin haɗin yanar gizo da adanawa. makamashi. yawan ofisoshi na ƙarshe. Bugu da kari, halaye na babban iya aiki, babban damar yin amfani da bandwidth, babban abin dogaro, da ayyuka masu yawa na QoS matakin goyon bayan damar hanyar sadarwa ta hanyar sadarwa suma sun sa juyin halittar hanyar sadarwa ta zama hadadden dandamali mai hadewa, hadewa, da ingantaccen ingantaccen dandamali.
2. Babban ka'idar hanyar sadarwa ta EPON
Tsarin EPON yana amfani da fasahar WDM don gane watsawar fiber guda ɗaya, ta yin amfani da madaidaicin 1310nm na sama da 1490nm mai tsayi don watsa bayanai da murya, yayin da sabis na CATV ke amfani da tsawon zangon 1550nm don ɗauka. An sanya OLT a ƙarshen ofishin tsakiya don rarrabawa da sarrafa haɗin tashar tashar, kuma yana da kulawa na ainihi, gudanarwa da ayyukan kulawa. Ana sanya ONU a gefen mai amfani, kuma OLT da ONU an haɗa su a cikin yanayin 1:16/1:32 ta hanyar hanyar sadarwa mai rarraba kayan gani.
Domin raba siginar zagaye-zagaye na masu amfani da yawa akan fiber iri ɗaya, ana iya amfani da waɗannan dabaru iri-iri guda biyu masu zuwa.
1) The downlink data rafi rungumi dabi'ar watsa shirye-shirye. A cikin EPON, ana aika tsarin watsa bayanan ƙasa daga OLT zuwa ONU masu yawa ta hanyar watsa bayanai. Ana watsa bayanai a ƙasa daga OLT zuwa ONU masu yawa a cikin nau'i na fakiti masu tsayi masu tsayi. Kowane fakitin bayanin yana da taken EPON, wanda ke nuna musamman ko an aika fakitin bayanin zuwa ONU-1, ONU-2 ko ONU-3. Hakanan ana iya gano shi azaman fakitin watsa shirye-shirye zuwa duk ONUs ko zuwa takamaiman rukunin ONU (fakitin multicast). Lokacin da bayanan suka isa ONU, ONU tana karɓar kuma ta gane fakitin bayanan da aka aika zuwa gare ta ta hanyar daidaita adireshin, kuma ta watsar da fakitin bayanan da aka aika zuwa wasu ONUs. Bayan an yi rijistar ONU a matsayin mai aiki, ana ware LLID na musamman; lokacin da OLT ya karɓi bayanai, yana kwatanta lissafin rajista na LLID. Lokacin da ONU ta karɓi bayanai, kawai tana karɓar firam ko firam ɗin watsa shirye-shiryen da suka dace da nata LLID.
2) Rafin bayanai na sama yana ɗaukar fasahar TDMA. OLT yana kwatanta lissafin rajista na LLID kafin karɓar bayanai; kowane ONU yana aika da firam ɗin bayanai a cikin lokacin da aka ware daidai da kayan aikin ofishin OLT; Ramin lokacin da aka keɓance (ta hanyar fasahar kewayon) yana rama bambancin tazara tsakanin kowane ONU kuma yana guje wa kowane karo na ONU tsakanin.
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