Gabatarwar tsarin PON daban-daban
1. Fasahar APON
A tsakiyar shekarun 1990, wasu manyan kamfanonin sadarwa sun kafa Full Service Access Network Alliance (FSAN), wadda manufarta ita ce samar da wani tsari na bai daya na kayan aikin PON ta yadda masana'antun da masu sarrafa kayan aiki za su iya shiga kasuwar kayan aikin PON su yi gasa tare. Sakamakon farko shine ƙayyadaddun tsarin tsarin PON na 155Mbit / s a cikin jerin shawarwarin ITU-T G.983. Domin ana amfani da ATM a matsayin yarjejeniya, wannan tsarin shi ake kira APON system, kuma galibi ana fahimtarsa cewa yana samar da sabis na ATM ne kawai. Saboda haka, an sake masa suna Broadband Passive Optical Network (BPON) tsarin don nuna cewa wannan tsarin zai iya samar da sabis na Broadband na Ethernet kamar damar hanyar sadarwa, rarraba bidiyo, da manyan layin haya. Koyaya, ga wannan ƙarni na tsarin FSAN, sunan da aka fi amfani dashi shine APON. Daga baya, an inganta ma'auni na APON, kuma ya fara tallafawa ƙimar 622 Mbit / s downlink, kuma an ƙara sabbin abubuwa cikin hanyoyin kariya, ƙayyadaddun bandwidth mai ƙarfi (DBA), da sauran fannoni.
APON yana amfani da ATM azaman ka'idar mai ɗaukar kaya. Watsawa ƙasa rafi ne mai ci gaba na ATM tare da ƙimar bit na 155.52Mbit / s ko 622.08Mbit / s. Ana shigar da tantanin halitta na musamman na sarrafa aiki da kulawa (PLOAM) a cikin rafin bayanai. Watsawa na sama shine ƙwayoyin ATM a cikin fashe. Don cimma fashewar watsawa da liyafar, ana ƙara sama da sama na 3-byte a gaban kowace tantanin halitta mai 53-byte. Don ƙimar asali na 155.52 Mbit / s, ƙa'idar watsawa ta dogara ne akan firam ɗin ƙasa wanda ke ɗauke da sel 56 ATM (bytes 53 kowace tantanin halitta); Lokacin da aka ƙara ƙimar bit zuwa 622.08 Mbit / s, an faɗaɗa firam ɗin ƙasa zuwa 224 Cell. A ainihin ƙimar 155.52 Mbit / s, tsarin firam ɗin uplink shine sel 53, kowane tantanin halitta shine 56 bytes (53 bytes ATM da 3 bytes sama). Baya ga sel bayanan 54 a cikin firam ɗin ƙasa, akwai ƙwayoyin PLOAM guda biyu, ɗaya a farkon firam ɗin ɗayan kuma a tsakiyar firam. Kowane tantanin halitta na PLOAM ya ƙunshi izinin watsa sama don takamaiman tantanin halitta a cikin firam na sama (53 Ƙwayoyin firam na sama suna da tallafin 53 da aka tsara cikin ƙwayoyin PLOAM) da bayanan OAM & P. APON yana ba da arziƙi sosai kuma cikakke ayyukan OAM, gami da saka idanu akan ƙimar kuskuren bit, mai ban tsoro, ganowa ta atomatik, da bincike ta atomatik. A matsayin tsarin tsaro, yana iya rutsawa da rufaffen bayanan da ke ƙasa.
Daga mahangar sarrafa bayanai, a cikin APON, dole ne a watsa bayanan mai amfani a ƙarƙashin canjin yarjejeniya (AAL1/2 don TDM da AAL5 don watsa fakitin bayanai). Wannan jujjuyawar yana da wuyar daidaitawa zuwa babban bandwidth, kuma kayan aikin da ke yin wannan aikin sun haɗa da wasu kayan aikin taimako masu alaƙa, irin su ƙwaƙwalwar ƙwayar cuta, Glue Logic, da sauransu, wanda kuma yana ƙara yawan farashin tsarin.
Yanzu, ko cibiyar sadarwa ce mai nisa mai nisa ko babban yanki na samun damar hanyar sadarwa ta hanyar sadarwa, fasahar sadarwar dijital sannu a hankali ta canza daga ATM-centric zuwa tushen IP don samar da bidiyo, sauti, da sadarwar bayanai. Sabili da haka, kawai tsarin hanyar sadarwa na hanyar sadarwa wanda zai iya daidaitawa zuwa duka damar shiga na yanzu da kuma fasahar cibiyar sadarwa na gaba na gaba zai iya sa makomar gaba ta IP ta zama gaskiya.
A hankali APON ya janye daga kasuwa saboda sarkakiyar sa da kuma karancin isar da bayanai.
2. EPON
Kusan a lokaci guda da tsarin APON, IEEE kuma ya kafa ƙungiyar bincike ta farko ta hanyar Ethernet (EFM) don ƙaddamar da EPON (Ethernet Passive Optical Network) na tushen Ethernet dangane da hanyoyin sadarwar fiber, yana nuna kyakkyawar kasuwa. Ƙungiyar binciken na cikin ƙungiyar IEEE 802.3 wacce ta haɓaka daidaitattun Ethernet. Hakazalika, iyakar bincikensa kuma yana iyakance ga gine-gine, kuma dole ne ya dace da ayyukan Layer na 802.3 na samun damar shiga kafofin watsa labarai (MAC). A cikin Afrilu 2004, ƙungiyar bincike ta gabatar da daidaitattun IEEE 802.3ah don EPON, tare da haɓakawa da haɓaka ƙimar 1 Gbit / s (ta amfani da lambar 8B / 10B, da ƙimar layin 1.25 Gbit / s), yana kawo ƙarshen masana'antun EPON. amfani da ka'idoji masu zaman kansu don haɓaka matsayin daidaitaccen kayan aiki.
EPON shine tsarin shiga yanar gizo dangane da fasahar Ethernet. Yana amfani da PON topology don aiwatar da damar Ethernet. Mabuɗin fasahar layin haɗin bayanan sun haɗa da: Multiple Access Control Protocol (MPCP) don tashar haɗin kai, toshewa da matsalar wasaONU, da jeri da jinkirta ka'idojin diyya naOLT, da kuma al'amurran da suka dace da yarjejeniya.
Layer na zahiri na IEEE 802.3ah ya haɗa da duka-duka-zuwa-aya (P2P) filayen gani na gani da wayoyi na jan karfe, da kuma yanayin hanyar sadarwa na PON don maki-zuwa-multipoint (P2MP). Domin sauƙaƙe aikin cibiyar sadarwa da gyara kuskure, ana kuma haɗa tsarin OAM. Domin P2MP cibiyar sadarwa topology, EPON dogara ne a kan wani inji da ake kira Multipoint Control Protocol (MPCP), wanda shi ne aiki a cikin MAC sublayer. MPCP yana amfani da saƙonni, injinan jihohi, da masu ƙidayar lokaci don sarrafa damar zuwa cibiyar sadarwar P2MP. Kowane naúrar hanyar sadarwa ta gani (ONU) a cikin P2MP cibiyar sadarwa topology yana da mahaɗin ladabi na MPCP wanda ke sadarwa tare da mahaɗin yarjejeniyar MPCP a cikinOLT. .
Tushen ka'idar EPON/MPCP shine sublayer simulation na aya-zuwa-aya, wanda ke sa hanyar sadarwar P2MP ta yi kama da tarin hanyoyin haɗin P2P zuwa manyan yadudduka na yarjejeniya.
Domin rage farashin daONU, Mabuɗin fasahar EPON na zahiri sun mayar da hankali kanOLT, gami da aiki tare da sauri na fashe sigina, aiki tare na cibiyar sadarwa, sarrafa iko na na'urorin transceiver na gani, da liyafar daidaitacce.
EPON ya haɗu da fa'idodin PON da samfuran bayanan Ethernet don samar da fa'idodi na musamman. Tsarin EPON na iya samar da haɓakar haɗin kai da saukar da bandwidth har zuwa 1 Gbit / s, wanda zai iya biyan bukatun masu amfani a nan gaba na dogon lokaci. EPON yana amfani da fasaha mai yawa don tallafawa ƙarin masu amfani, kuma kowane mai amfani zai iya jin daɗin bandwidth mafi girma. Tsarin EPON baya amfani da kayan ATM masu tsada da kayan SONET, kuma yana dacewa da Ethernet data kasance, yana sauƙaƙa tsarin tsarin sosai, ƙarancin farashi, da sauƙin haɓakawa. Saboda dadewar rayuwar na'urorin gani na gani, farashin kula da layin waje yana raguwa sosai. A lokaci guda, daidaitattun hanyoyin sadarwa na Ethernet na iya cin gajiyar kayan aikin Ethernet maras tsada da ke akwai kuma ya adana farashi. Tsarin PON da kansa yana ƙayyade cewa hanyar sadarwa tana da girma sosai. Muddin an maye gurbin kayan aikin tasha, ana iya haɓaka hanyar sadarwar zuwa 10 Gbit/s ko sama. EPON ba zai iya haɗa TV ɗin kebul na yanzu ba, bayanai da sabis na murya, amma kuma ya dace da ayyuka na gaba kamar dijital TV, VoIP, taron bidiyo da VOD, da dai sauransu, don cimma haɗin haɗin sabis.
Cikakken amfani da mai ɗaukar EPON da sauran fasahohin samun dama yana ƙara wadatar hanyoyin fasahar samun damar buɗaɗɗen.
Yin amfani da EPON na iya sa DSL karya ƙayyadaddun nisa na gargajiya da faɗaɗa ɗaukar hoto. Lokacin daONUAn haɗa shi cikin Digital Subscriber Line Access Multiplexer (DSLAM), kewayon DSL da yuwuwar rukunin masu amfani zai ƙaru sosai.
Hakazalika, ta hanyar haɗa CMTS (Cable Modem Termination System) naONU, EPON na iya samar da bandwidth zuwa hanyoyin haɗin Cable na yanzu, kuma ya ba da damar masu amfani da kebul don aiwatar da ayyukan haɗin gwiwar gaske yayin da rage farashin gini da aiki.
A cikin duka biyun, masu aiki zasu iya haɓaka tushen mai amfani bisa tsarin hanyar sadarwar da suke da su da kuma saka hannun jari. EPON kuma na iya tsawaita maki-zuwa-maki MSPP (Platform Samar da Sabis da yawa) da IP / Ethernet.
Bugu da ƙari, ana iya amfani da fasahar EPON don magance matsalar haɓakar bayanan da aka haɗa ta tashar tushe a cikin fasahar shiga mara waya da aka haɗa zuwa cibiyar sadarwar.
3.GPON
A cikin 2001, FSAN ta ƙaddamar da wani sabon ƙoƙari don daidaita hanyoyin sadarwar PON da ke aiki sama da 1 Gbit / s. Baya ga tallafawa manyan ƙima, duk yarjejeniya ta buɗe don sake tunani da nemo mafi kyawun mafita mafi inganci dangane da tallafawa sabis da yawa, ayyukan OAM & P da haɓakawa. A wani bangare na aikin GPON, FSAN ta fara tattara bukatun dukkan membobinta (ciki har da manyan kamfanoni a duniya), sannan a kan haka, ta rubuta takarda mai suna Gigabit Service Requirements (GSR) kuma ta ba da shawara ga hukuma (G.GON. GSR) zuwa ITU-T. Babban buƙatun GPON da aka kwatanta a cikin fayil ɗin GSR sune kamar haka.
l Yana goyan bayan cikakkun ayyuka, gami da murya (TDM, SONET / SDH), Ethernet (10/100 Base-T), ATM, layin haya, da sauransu.
l Nisan jiki da aka rufe shine aƙalla 20km, kuma nisa mai ma'ana yana iyakance zuwa 60km.
l Yana goyan bayan ƙimar bit iri daban-daban ta amfani da yarjejeniya iri ɗaya, gami da madaidaicin 622 Mbit / s, madaidaicin 1.25 Gbit / s, ƙasa 2.5 Gbit / s da sama 1.25 Gbit / s, da sauran ƙimar bit.
l OAM & P ayyuka masu ƙarfi waɗanda zasu iya ba da kulawar sabis na ƙarshe zuwa ƙarshen.
l Saboda halayen watsa shirye-shirye na PON, dole ne a ba da garantin tsaro na ayyukan ƙasa a matakin yarjejeniya.
FSAN ta ba da shawarar cewa zayyana ma'aunin GPON ya dace da manufofin da ke gaba.
l Za a iya fadada tsarin firam daga 622Mbit / s zuwa 2.5Gbit / s, kuma yana goyan bayan ƙimar bit asymmetric.
l Garanti babban amfani da bandwidth da ingantaccen inganci ga kowane kasuwanci.
l Sanya kowane sabis (TDM da fakiti) cikin firam 125ms ta hanyar GFP.
l watsawa mai inganci da kyauta na sabis na TDM masu tsafta.
l Rarraba bandwidth mai ƙarfi ga kowaneONUta hanyar ma'anar bandwidth.
Tunda GPON ya sake duba aikace-aikace da buƙatun PON tun daga ƙasa zuwa sama, ya kafa harsashin sabon mafita kuma ba ya dogara da ƙa'idar APON da ta gabata, don haka wasu masana'antun suna kiranta na asali PON (natural mode PON). A gefe guda, GPON yana riƙe da ayyuka da yawa waɗanda basu da alaƙa kai tsaye da PON, kamar saƙonnin OAM, DBA, da sauransu. GFP (tsarin ƙira na gabaɗaya) wanda FSAN ya zaɓa ƙa'idar tushen firam ce wacce ke daidaita bayanan sabis daga manyan abokan cinikin hanyar sadarwar sufuri ta hanyar gama gari. Hanyoyin sadarwa na iya zama kowane nau'i na hanyar sadarwa, kamar SONET / SDH da ITU-T G.709 (OTN), da dai sauransu. Bayanan abokin ciniki na iya zama tushen fakiti (kamar IP / PPP, watau IP / Point to Point Protocal). , ko Ethernet MAC Frames, da dai sauransu), Hakanan zai iya zama madaidaicin rafi ko wasu nau'ikan bayanan kasuwanci. GFP an daidaita shi bisa hukuma azaman ITU-T misali G.7041. Saboda GFP yana ba da ingantacciyar hanya mai sauƙi don watsa ayyuka daban-daban akan hanyar sadarwa ta aiki tare, yana da kyau a yi amfani da shi azaman tushen GPON TC Layer. Bugu da ƙari, lokacin amfani da GFP, GPON TC yana aiki tare da gaske kuma yana amfani da daidaitattun firam ɗin SONET/SDH 8kHz (125ms), wanda ke ba GPON damar tallafawa ayyukan TDM kai tsaye. A cikin ƙa'idar G.984.3 da aka fitar a hukumance, shawarar FSAN akan GFP yayin da aka karɓi fasahar gyare-gyaren Layer na TC, kuma an ƙara sauƙaƙe aiki, mai suna GPON hanyar encapsulation (GEM, GPONEncapsulationMethod).
Aikace-aikacen tsarin EPON
EPON, a matsayin sabuwar fasahar samun hanyar sadarwa, wani dandamali ne na samar da cikakken sabis wanda zai iya tallafawa ayyukan bayanai da kuma ayyuka na ainihi kamar murya da bidiyo.
Tsarin hanyar gani na EPON na iya amfani da tsawon raƙuman ruwa 3. Idan baku yi la'akari da tallafawa ayyukan CATV ko DWDM ba, ana amfani da tsayin raƙuman ruwa guda biyu gabaɗaya. Lokacin amfani da tsawon raƙuman raƙuman ruwa 3, tsayin raƙuman ruwa na sama shine 1310nm, madaidaicin raƙuman ruwa shine 1490nm, an ƙara ƙarin tsayin 1550nm. Ana amfani da ƙaƙƙarfan tsayin igiyoyin 1550nm don watsa siginar bidiyo na analog kai tsaye. Saboda siginar bidiyo na analog na yanzu yana mamaye ayyukan rediyo da talabijin, an kiyasta cewa ba za a maye gurbinsa gaba ɗaya da sabis na bidiyo na dijital ba har sai 2015. Saboda haka, tsarin EPON da aka tsara a halin yanzu yakamata ya goyi bayan sabis na bidiyo na dijital da sabis na bidiyo na analog. 1490nm na asali har yanzu yana ɗaukar bayanan ƙasa, bidiyo na dijital da sabis na murya, kuma 1310nm yana watsa siginar muryar mai amfani da haɓaka, bidiyo na dijital akan buƙata (VOD), da neman bayanai don zazzage bayanai.
Siginonin murya suna da tsauraran buƙatu akan jinkiri da jitter, kuma Ethernet baya samar da jinkirin fakitin ƙare-zuwa-ƙarshe, ƙimar fakitin fakiti, da ikon sarrafa bandwidth. Don haka, yadda ake tabbatar da ingancin sabis lokacin da EPON ke haɓaka siginar murya matsala ce ta gaggawa da za a warware.
1. TDM kasuwanci
A halin yanzu, mafi yawan abin tambaya game da damar sabis na EPON shine ikonsa na watsa ayyukan TDM na gargajiya.
Ayyukan TDM da aka ambata anan sun haɗa da nau'ikan sabis na murya guda biyu (POTS, Mashahurin Tsohon Wayar Waya) da sabis na kewayawa (T1 / El, N'64kbit / s layukan hayar).
Lokacin da tsarin EPON ke ɗaukar sabis na sadaukar da bayanai (2048kbit / s ko 13'64kbit / s sabis na bayanan), ana ba da shawarar TDM akan Ethernet. Tsarin EPON na iya ɗaukar juyawa da'ira ko VolP lokacin ɗaukar sabis na murya.
A cikin 'yan shekaru masu zuwa, saboda har yanzu buƙatun kasuwa na sabis na kewaya yana da girma sosai, ana buƙatar tsarin EPON don ɗaukar fakiti biyu-canzaayyuka da kewaye-canzaayyuka. Ta yaya EFM ke ɗaukar TDM akan EPON da yadda ake tabbatar da ingancin ayyukan TDM. Babu takamaiman tanadi a fasaha, amma dole ne su dace da tsarin firam ɗin Ethernet. Multi-service EPON (MS-EPON) yana ɗaukar fasahar E1 Over Ethernet, wanda ke magance matsalar daidaita ayyukan TDM akan firam ɗin Ethernet, yana ba EPON damar fahimtar watsa sabis da dama. A lokaci guda, MS-EPON ya shawo kan rata tsakaninOLTkumaONU. Lamarin rikice-rikicen bandwidth da aka raba yana ba masu amfani da Ethernet tabbacin garantin bandwidth.
Hanyar encapsulation na Ethernet ya sa fasahar EPON ta dace sosai don ɗaukar ayyukan IP, amma kuma tana fuskantar babbar matsala - yana da wuya a ɗauka ayyukan TDM kamar bayanan murya ko kewaye. EPON cibiyar sadarwa ce ta asynchronous ta tushen Ethernet. Ba shi da madaidaicin agogo mai aiki tare a cikin hanyar sadarwa, kuma yana da wahala a cika buƙatun lokaci da aiki tare na sabis na TDM. Don warware matsalar daidaita lokaci na ayyukan TDM yayin tabbatar da matsalolin fasaha kamar QoS na ayyukan TDM, dole ne mu ba kawai inganta ƙirar tsarin EPON kanta ba, har ma muna buƙatar ɗaukar wasu takamaiman fasaha.
Ma'anar aikin kewayawacanzaSabis na murya yana nuna cewa lokacin da tsarin EPON yayi amfani da kewayecanzaHanyar ɗaukar sabis na murya, ya kamata ya dace da buƙatun YDN 065-1997 "Ƙararren Ƙwararren Ƙwararren Ƙwararren Watsa Labarai na Ma'aikatar Watsa Labarai da Sadarwa" da YD / T 1128-2001 ) “bukatun don zagayawa mai tsaftacanzaingancin murya. Saboda haka, EPON a halin yanzu yana da matsaloli masu zuwa tare da ayyukan TDM.
① Sabis na TDM garantin QoS: Ko da yake bandwidth ɗin da sabis ɗin TDM ya mamaye yana ƙarami, yana da manyan buƙatu akan alamomi kamar jinkirtawa, jitter, drift, da ƙimar kuskuren bit. Wannan yana buƙatar ba kawai don la'akari da yadda za a rage jinkirin watsawa da jitter na sabis na TDM yayin rarraba bandwidth mai ƙarfi ba, har ma don tabbatar da cewa sabis ɗin TDM yana sarrafa tsaiko da jitter a cikin dabarun sarrafa bandwidth na ƙasa.
② Lokaci da aiki tare na sabis na TDM: Ayyukan TDM suna da takamaiman buƙatu akan lokaci da aiki tare. EPON ainihin hanyar sadarwar watsawa ce ta asynchronous dangane da fasahar Ethernet. Babu madaidaicin agogon sadarwa da aka daidaita a ko'ina cikin hanyar sadarwa. Daidaiton agogon da Ethernet ya ayyana shine ± 100′10 kuma daidaiton agogon da sabis na TDM na gargajiya ke buƙata shine ± 50′10. Bugu da kari, yayin samar da agogon sadarwa da ke aiki tare a ko'ina cikin hanyar sadarwa, dole ne a watsa bayanan TDM lokaci-lokaci don saduwa da buƙatun jitter da kuskure.
③ Rayuwar EPON: Sabis ɗin TDM kuma yana buƙatar cewa cibiyar sadarwar mai ɗaukar nauyi dole ne ta sami ingantaccen rayuwa. Lokacin da babbar gazawa ta faru, sabis ɗin na iya zama abin dogarocanzaa cikin mafi kankantar lokaci mai yiwuwa. Saboda ana amfani da EPON galibi don gina hanyar sadarwa, yana da kusanci da masu amfani, kuma aikace-aikace daban-daban da yanayin amfani suna da rikitarwa. Abubuwan da ba a san su ba kamar gine-ginen birane suna shafar shi cikin sauƙi, yana haifar da haɗari kamar katsewar hanyar haɗin gwiwa. Sabili da haka, ana buƙatar tsarin EPON cikin gaggawa don samar da tsarin kariya mai tsada mai tsada.
2. Ayyukan IP
EPON yana watsa fakitin bayanan IP ba tare da canza yarjejeniya ba kuma yana da inganci sosai, wanda ya dace da sabis na bayanai.
Fasahar VolP, a matsayin fasaha mai zafi a cikin ci gaba, ta cimma wani ma'auni na aikace-aikace a cikin 'yan shekarun nan, kuma hanya ce mai mahimmanci don ɗaukar sabis na murya akan hanyoyin sadarwar IP. A cikin tsarin EPON, kuma yana yiwuwa a aiwatar da damar yin amfani da sabis na tarho na gargajiya ta hanyar ƙara wasu kayan aikin VoIP ko ayyuka. Yin amfani da fasahar VoIP, idan dai an tabbatar da jinkiri da halayen jitter na sabis na murya na EPON, ana barin sauran ayyuka zuwa na'urar haɗakarwa ta gefen mai amfani (IAD, Integrated Access Device) da na'urar ƙofa ta tsakiya don aiwatar da sabis na murya. Watsawa Wannan hanyar tana da sauƙin aiwatarwa kuma tana iya kai tsaye tashar jiragen ruwa data kasance, amma tana buƙatar kayan aikin shiga ofis na tsakiya masu tsada, tsadar ginin cibiyar sadarwa, kuma an iyakance ta da gazawar fasahar VoIP kanta. Bugu da kari, E1 da N'64kbit / s data sabis ba za a iya samar.
Lokacin da tsarin EPON yayi amfani da VoIP don ɗaukar sabis na murya, ya kamata ya dace da waɗannan alamun aiki don sabis na muryar VoIP.
① Lokacin canza murya mai ƙarfi bai wuce 60ms ba.
② Ya kamata ya kasance yana da ƙarfin ma'auni na 80ms don tabbatar da cewa babu yanke magana da jitters da ke faruwa.
③ Maƙasudin kimanta murya: Lokacin da yanayin cibiyar sadarwa yayi kyau, matsakaicin ƙimar PSQM bai wuce 1.5 ba; lokacin da yanayin cibiyar sadarwa ba su da kyau (kuɗin asarar fakiti = 1%, jitter = 20ms, jinkiri = 100ms), matsakaicin ƙimar PSQM shine <1.8; Lokacin da sharuɗɗan ba su da kyau (ƙididdigar asarar fakiti = 5%, jitter = 60ms, jinkiri = 400ms), matsakaicin PSQM bai wuce 2.0 ba.
④ Mahimman ƙima na magana: Lokacin da yanayin sadarwar ke da kyau, matsakaicin ƙimar MOS shine> 4.0; lokacin da yanayin sadarwar ba su da kyau (asara fakiti = 1%, jitter = 20ms, jinkirta = 100ms), matsakaicin darajar MOS shine <3.5; cibiyar sadarwa Lokacin da yanayi ba su da kyau (kuɗin asarar fakiti = 5%, jitter = 60ms, jinkiri = 400ms), matsakaicin ƙimar MOS <3.0.
⑤ Ƙimar ɓoyewa: G.711, ƙimar ɓoyewa = 64kbit / s. Don G.729a, ƙimar coding da ake buƙata shine <18kbit / s. Domin G.723.1, G.723.1 (5.3) yawan coding shine <18kbit / s, kuma G.723.1 (6.3) adadin coding shine <15kbit / s.
⑥ Ma'anar jinkiri (jinkirin madauki): Jinkirin VoIP ya haɗa da jinkirin codec, jinkirin shigar da buffer a ƙarshen karɓa, da jinkirin layi na ciki. Lokacin da G.729a aka yi amfani da ɓoye, jinkirin madauki shine <150ms. Lokacin da G.723.1 aka yi amfani da ɓoye, jinkirin madauki shine <200ms.
3.CATV kasuwar kasuwa
Don ayyukan CATV na analog, ana iya ɗaukar EPON kamar yadda GPON: ƙara tsawon zango (a gaskiya wannan fasaha ce ta WDM kuma ba ta da alaƙa da EPON da GPON kanta).
Fasahar PON ita ce hanya mafi kyau don samun damar shiga FTTx. EPON sabuwar fasaha ce ta hanyar sadarwar gani da aka kirkira ta hanyar hada fasahar Ethernet da fasahar PON. Ana iya amfani da shi don watsa murya, bayanai da sabis na bidiyo kuma yana dacewa. Ga wasu sabbin ayyuka a nan gaba, EPON za ta zama babbar fasaha don samun cikakkiyar hanyar sadarwa ta hanyar sadarwa tare da cikakkiyar fa'idodinsa kamar babban bandwidth, inganci mai inganci, da sauƙin haɓakawa.
Tsarin kariya na tsarin PON
Domin inganta amincin cibiyar sadarwa da rayuwa, ana iya amfani da tsarin canza yanayin kariyar fiber a cikin tsarin PON. Ana iya aiwatar da tsarin canza yanayin kariyar fiber na gani ta hanyoyi biyu: ① sauyawa ta atomatik, wanda aka gano ta hanyar gano kuskure; ② sauyawar tilastawa, wanda abubuwan gudanarwa suka jawo.
Akwai manyan nau'ikan kariyar fiber guda uku: kariyar kariyar fiber kashin baya,OLTPON kariyar sake dawowa tashar jiragen ruwa, da cikakken kariya, kamar yadda aka nuna a hoto 1.16.
Kariyar rashin aikin fiber na baya (Hoto 1.16 (a)): Yin amfani da tashar PON guda ɗaya tare da ginanniyar 1'2 na gani.canzaa cikinOLTtashar PON; ta amfani da 2: N mai raba kayan gani; daOLTyana gano matsayin layi; Babu buƙatu na musamman donONU.
OLTPON tashar jiragen ruwa kariya kariya (Hoto 1.16 (b)): Tashar PON jiran aiki yana cikin yanayin jiran aiki mai sanyi, ta amfani da 2: N mai raba gani; daOLTyana gano matsayin layin, kuma ana yin sauyawa ta hanyarOLT, ba tare da buƙatu na musamman donONU.
Cikakken kariya (Hoto 1.16 (c)): duka manyan tashoshin PON da madaidaicin suna cikin yanayin aiki; biyu 2: N Ana amfani da masu rarraba kayan gani; na ganicanzaan gina shi a gabanONUPON tashar jiragen ruwa, da kumaONUyana gano matsayin layin kuma yana ƙayyade babban amfani Layuka da sauyawa ana yin su ta hanyarONU.
Tsarin sauyawa na kariyar tsarin PON na iya tallafawa dawowa ta atomatik ko dawo da sabis ɗin da aka kare da hannu. Don yanayin dawowa ta atomatik, bayan kawar da gazawar sauyawa, bayan wani takamaiman lokacin jiran dawowar, sabis ɗin da aka kare yakamata ya dawo ta atomatik zuwa asalin hanyar aiki. Za a iya saita lokacin jiran dawowa.