Na farko, wace matsala ake amfani da PON don magancewa?
● Tare da bayyanar manyan ayyuka na bandwidth irin su bidiyo akan buƙata, wasanni na kan layi da IPTV, masu amfani suna buƙatar gaggawa don haɓaka bandwidth. hanyar watsa iyawa, da tsaro.
● Saboda nisan watsawa mai tsayi, ƙarfin hana tsangwama mai ƙarfi da babban ƙarfin aiki, fiber na gani an yi amfani da shi sosai a cikin cibiyar sadarwa na baya. A cikin 'yan shekarun nan, tare da raguwar farashin na'urar na'ura mai mahimmanci, fiber na gani a hankali ya zama zabi na farko don watsawa na hanyar sadarwa.
● Passive Optical Network (PON) yana da ƙarancin farashi a yanayin samun fiber kuma ana iya haɓaka shi lafiya. Ana ƙara samun tagomashi daga ma'aikatan sadarwa kuma ana ɗaukarsa a matsayin ingantacciyar mafita don magance matsalar "mile na ƙarshe".
Na biyu, abun da ke ciki na PON
PON ya ƙunshi sassa uku: ƙarewar layin gani (OLT), naúrar hanyar sadarwa ta gani (ONU), da kuma mai raba gani na gani (POS).
PON tsari ne na asymmetric, point-to-multipoint (P2MP). Ayyukan daOLTda kumaONUsun bambanta. TheOLTdaidai yake da aikin Jagora, da kumaONUdaidai yake da matsayin Bawa.
Na uku, amfanin PON:
● Ajiye
P2P - N fiber na gani; 2N transceiver na gani
P2PCurb - 1 fiber; 2N + 2 transceiver na gani; yana buƙatar samar da wutar lantarki na gida; yana adana fiber mai yawa
P2MP (PON) - 1 fiber; N+1 mai ɗaukar hoto; adadi mai yawa na fiber na gani da aka ajiye; adadi mai yawa na transceivers na gani
● Abin dogaro
Siginar ba ta wucewa ta na'urar lantarki mai aiki a lokacin tsarin watsawa na PON, yana rage girman yiwuwar gazawar;
Yin amfani da na'urori marasa amfani yana sauƙaƙa tsarin tsarin cibiyar sadarwa, kuma ƙaƙƙarfan tsarin cibiyar sadarwa yana da sauƙin kulawa da sarrafawa.
● Nisa mai tsayi
Nisan watsawa na PON shine 10 zuwa 20km, wanda gaba ɗaya ya shawo kan iyakancewar nisa tsakanin hanyoyin samun damar Ethernet da xDSL, kuma yana haɓaka sassauci sosai na tura ofishin mai aiki na ƙarshe.
● Babban bandwidth
Idan aka kwatanta da xDSL, PON yana da bandwidth mafi girma kuma yana cika bukatun ayyukan watsa shirye-shiryen kan layi na HDTV na gaba.
● M
Samfurin sadarwar PON ba shi da iyaka, kuma ana iya gina hanyar sadarwar itace da topology a sassauƙa.
PON ya dace musamman ga lokatai da wuraren samun damar mai amfani ke warwatse, kuma fiber na gani na akwati na iya gamsar da duk masu amfani don samun damar wuraren bayanai.
Na hudu, babban ma'aunin PON
● GPON - GigabitPON, ITUG.984 ka'idar yarjejeniya, haɓakawa da haɓaka APON, ta amfani da tsarin tsari na gama gari don ba da tallafi ga ayyuka daban-daban. Matsakaicin ƙimar shine 2.5Gbps. GPON yana da abũbuwan amfãni a cikin babban gudu da goyon baya ga ayyuka da yawa, amma fasaha yana da rikitarwa, farashi yana da girma, kuma balagaggen samfurin ba shi da yawa.
● EPON ——Ethernetover PON, IEEE802.3ah ƙa'idar yarjejeniya, wanda ke watsa fakitin tsarin Ethernet akan hanyar sadarwar PON kuma yana iya tallafawa ƙimar ƙimar 1.25Gbps. EPON ya dogara ne akan fasahar Ethernet kuma ƙa'idar tana da sauƙi da inganci. Idan aka kwatanta da APON, GPON yana da fa'idodi a bayyane ta fuskar farashi.
Na biyar, Mabuɗin fasahar EPON
● Yawan tashoshi
Tsarin EPON yana ɗaukar fasahar WDM don gane watsawar fiber guda ɗaya;
Adadin tashar shine 1.25 Gbps sama da ƙasa.
● Yanayin watsa yanayin ƙasa na EPON - yanayin watsa shirye-shirye
● Yanayin watsa sama na EPON - Yanayin TDMA
● Yarjejeniyar Kula da Multipoint - MPCP
Ba kamar tsarin gine-ginen P2P na Ethernet ba, PON shine tsarin P2MP. TheONUyana gasa don samun albarkatun tashoshi masu haɓakawa, kuma ana buƙatar tsarin sasantawa don guje wa haɗuwar bayanan haɗin kai da kuma rarraba albarkatun tashoshi yadda ya kamata. Yarjejeniyar 802.3ah ta ƙayyade ƙa'idar kulawa da ta dace, Ƙa'idar Kulawa ta MAC Control Protocol (MPCP);
lMPCP galibi yana bayyana ma'anar sublayer na MAC Control-point Multi-point don ƙarawa da maye gurbin sublayer na MAC Control wanda aka ayyana ta hanyar 802.3. Firam ɗin sarrafawa na ƙa'idar MPCP yana da fifiko mafi girma fiye da firam ɗin bayanan MAClient.
● Ragewa da jinkirta diyya
Watsawa ta sama ta EPON tana ɗaukar yanayin TDMA. TheOLTyana ƙayyade lokacin donONUdon aika bayanai. Tun kowaceONUdaban da naOLT, za a sami bambancin jinkiri. Idan babu ingantacciyar hanyar biyan diyya mai inganci, har yanzu rikicin watsa bayanai na haɓaka zai faru.
Matsakaicin EPON da jinkirin ramuwa sune mabuɗin fasaha don haɓaka tashoshi mai yawa. Ø A cikin Tsarin Ganowa, daOLTyana ƙididdige ƙimar RTT (RoundTrip Time) na kowaneONUta hanyar auna sabon rijistaONU.
TheOLTyana amfani da RTT don daidaita lokacin izini na kowaneONU.
TheOLTHakanan zai iya fara farawa lokacin da ya karɓi MPCP PDU.
Lissafin RTT:
Firam ɗin GATE ya ƙunshi filin “timestamp” wandaONUyana amfani da shi don sabunta rajistar lokacin gida. TheOLTna iya lissafin RTT ta hanyar firam ɗin RAHOTO da aka karɓa don yin ramuwa na gwaji.
● Ƙididdigar Bandwidth mai ƙarfi (DBA)
Kwatanta ƙayyadaddun ramukan lokaci da ramummuka masu ƙarfi:
