Chii chinonzi PON?Broadband access tekinoroji iri kuwedzera, uye yakarongerwa kuve nhandare yehondo umo utsi husingazombofi hwakapera.Parizvino, hukuru hwepamba ichiri tekinoroji yeADSL, asi vagadziri vezvishandiso vanowedzera uye vashandisi vakaisa pfungwa kune tekinoroji yekuwana network.
Mitengo yemhangura inoramba ichikwira, mitengo yetambo inoramba ichidzikira, uye kuwedzera kuri kuda kweIPTV nemavhidhiyo mutambo masevhisi kuri kufambisa kukura kweFTTH.Tarisiro yakanaka yekutsiva tambo yemhangura newaya coaxial tambo netambo yekuona, nhare, tambo TV, uye Broadband data kutamba katatu inova pachena.
Mufananidzo 1: PON topology
PON (Passive Optical Network) passive optical network ndiyo tekinoroji huru yekuona FTTH faibha kumba, ichipa point-to-multipoint fiber kuwana, sezvakaratidzwa mumufananidzo 1, ndiyo OLT (optical line terminal) uye mushandisi wedivi hofisi side.Iyo ONU (Optical Network Unit) uye ODN (Optical Distribution Network) inoumbwa.Kazhinji, iyo downlink inotora TDM nhepfenyuro modhi uye iyo uplink inotora iyo TDMA (Time Division Multiple Access) maitiro kuti agadzire poindi-to-multipoint muti topology. .Chikuru chikuru chePON se tekinoroji yekuona ye "passive".Iyo ODN haina chero zvigadzirwa zvemagetsi zvinoshanda uye magetsi emagetsi.Ese anoumbwa nezvinongoita zvinhu zvakaita sezvipatsanuri, zvine manejimendi akaderera uye mutengo wekushandisa.
Nhoroondo yePON Development
Tsvagiridzo yehunyanzvi hwePON yakatanga muna 1995. Muna Gumiguru 1998, ITU yakagamuchira iyo ATM-based PON technology standard, G, inotsigirwa nesangano reFSAN (full service access network).983. Iyo inozivikanwawo seBPON (BroadbandPON).Muyero ndeye 155Mbps uye unogona kusarudza kutsigira 622Mbps.
EFMA (Ethernetin the First Mile Alliance) yakaunza pfungwa yeEthernet-PON (EPON) pakupera kwe2000 ine chiyero chekutumira che 1 Gbps uye chikwata chekubatanidza chinobva pane nyore Ethernet encapsulation.
GPON (Gigabit-CapablePON) yakarongwa nesangano reFSAN munaSeptember 2002, uye ITU yakagamuchira G muna March 2003. 984. 1 uye G. 984. 2 chibvumirano.G. 984.1 Hunhu hwese hweGPON access system hunotsanangurwa.G.984. 2 inotsanangura kugoverwa kwenyama kunoenderana nechikamu cheODN (Optical Distribution Network) yeGPON.Muna Chikumi 2004, ITU yakapfuura G zvakare.984. 3, iyo inotsanangura zvinodiwa zveTransmission Convergence (TC) layer.
Kuenzanisa kweEPON uye GPON zvigadzirwa
EPON neGPON ndidzo nhengo mbiri huru dzeOptical network access, imwe neimwe iine kwayo kwayo, ichikwikwidzana, ichizadzisana uye kudzidza kubva kune mumwe nemumwe.Izvi zvinotevera zvinovaenzanisa muzvikamu zvakasiyana-siyana:
Rate
EPON inopa yakagadziriswa uplink uye downlink ye1.25Gbps, uchishandisa 8b/10b mutsara wekodhi, uye chiyero chaicho i1Gbps.
GPON inotsigira magiredhi akawanda ekumhanya uye inogona kutsigira uplink uye downlink asymmetric kumhanya, 2.5Gbps kana 1.25Gbps pasi perwizi, uye 1.25Gbps kana 622Mbps uplink.Zvinoenderana nezvinodiwa chaizvo, iyo uplink uye downlink mazinga akatemerwa, uye anowirirana optical modules anosarudzwa kuti awedzere optical mudziyo wekumhanyisa mutengo ratio.
Mhedziso iyi: GPON iri nani pane EPON.
Split ratio
Chiyero chekupatsanura ndechekuti vangani maONU (vashandisi) vanotakurwa nechiteshi chimwe cheOLT (hofisi).
Iyo EPON chiyero inotsanangura chikamu chekupatsanura che1:32.
Iyo GPON chiyero inotsanangura kupatsanurwa reshiyo kune inotevera 1:32;1:64;1:128
Muchokwadi, tekinoroji yeEPON masisitimu anogonawo kuwana yakakwira kupatsanurwa ratios, senge 1:64, 1:128, EPON control protocol inogona kutsigira mamwe ONUs.Chiyero chemugwagwa chinonyanya kuganhurirwa nemaitiro ekuita kweiyo optical module, uye kupatsanurwa kukuru. chiyero chichaita kuti iyo optical module mutengo ukwire zvakanyanya.Pamusoro pezvo, iyo PON yekuisa kurasikirwa ndeye 15 kusvika 18 dB, uye yakakura kupatsanura reshiyo inoderedza kureba kwekutapurirana.Yakawandisa mushandisi kugovera bandwidth zvakare mutengo weiyo yakakura kupatsanura reshiyo.
Mhedziso iyi: GPON inopa kusarudzwa kwakawanda, asi kutariswa kwemutengo hakusi pachena.Iyo yakanyanya kureba yemuviri iyo iyo GPON system inogona kutsigira.Kana iyo optical split reshiyo iri 1:16, iyo yakakura yemuviri chinhambwe che20km inofanira kutsigirwa.Kana iyo optical split reshiyo iri 1:32, iyo yakakura yemuviri chinhambwe che10km inofanira kutsigirwa.EPON yakafanana,mhedziso iyi: kuenzana.
QOS (Hunhu hweSevhisi)
EPON inowedzera 64-byte MPCP(multi point control protocol) kuMAC header Ethernet musoro.MPCP inodzora kupinda kuP2MP point-to-multipoint topology kuburikidza nemeseji, michina yenyika, uye nguva yekushandisa DBA dynamic bandwidth kugoverwa. kugoverwa kweONU transmission time slots, kuwanikwa otomatiki uye kujoinwa kweONU, uye kushuma kwekusangana kune yakakwirira layers kugovera zvine simba bandwidth.MPCP inopa rubatsiro rwekutanga rweP2MP topology.Nekudaro, iyo protocol haigadzirise zvekutanga sevhisi.Masevhisi ese anokwikwidza zvisina tsarukano kune bandwidth.GPON ine DBA yakazara uye yakanakisa QoS sevhisi kugona.
GPON inokamura sevhisi bandwidth yekugovera nzira mumhando ina.Iyo inonyanya kukosha inogadziriswa (Yakagadziriswa), Yakavimbiswa, Isiri-Yakavimbiswa, uye BestEffort.Iyo DBA inotsanangura zvakare chigaba chetraffic (T-CONT) seuplink traffic yekuronga unit, uye imwe neimwe T-CONT inozivikanwa neAlloc-ID.T-CONT yega yega inogona kunge iine imwe kana anopfuura maGEMPort-IDs.T-CONT yakakamurwa kuita mhando shanu dzesevhisi.Mhando dzakasiyana dzeT-CONTs dzine maitiro akasiyana-siyana ekugoverwa kwebhanwidth, iyo inogona kusangana neQoS zvakasiyana-siyana zvinodiwa zvakasiyana-siyana zvekuyerera kwesevhisi kunonoka, jitter, uye packet kurasikirwa. a fixed-bandwidth (Fixed) allocation, akakodzera kunonoka-sensitive services, akadai sezwi rezwi.Type 2 inoratidzirwa neyakagadziriswa bandwidth asi indeterminate time slot.Iyo inoenderana yakavimbiswa bandwidth (Yakavimbiswa) yakagoverwa inokodzera yakagadziriswa bandwidth masevhisi ayo asingade yakakwira jitter, senge vhidhiyo pane inodiwa masevhisi.Rudzi rwechitatu runoratidzwa nediki bandwidth garandi uye kugovana kwakasimba kweiyo redundant bandwidth, uye ine chirambidzo chepamusoro bandwidth, inoenderana neasina-assured bandwidth (Non-Assured) allocation, akakodzera masevhisi ane sevhisi vimbiso zvinodiwa uye yakakura kuputika traffic.Zvakadai sekudhawunirodha bhizinesi.Type 4 inoratidzirwa neBestEffort, hapana bandwidth garandi, inokodzera masevhisi ane low latency uye jitter zvinodiwa, senge WEB browsing service.Rudzi rwe5 imhando yekubatanidza, mushure mekugovera yakavimbiswa uye isina-yakavimbiswa bandwidth, kuwedzera Izvo zvinodiwa bandwidth zvakagoverwa zvakanyanya sezvinobvira.
Mhedziso: GPON iri nani pane EPON
Shanda uye chengetedza OAM
EPON haina kunyanya kufunga nezveOAM, asi inongotsanangura ONT kure kure chiratidzo, loopback uye yekutarisa yekutarisa, uye inotsigira sarudzo.
GPON inotsanangura PLOAM (PhysicalLayerOAM) pachikamu chemuviri, uye OMTI (ONTMagementandControlInterface) inotsanangurwa pachikamu chepamusoro kuti iite OAM management pamatanho akawanda.PLOAM inoshandiswa kuita encryption data, kuona mamiriro, uye kuongorora kukanganisa.Iyo OMCI chiteshi protocol inoshandiswa kubata masevhisi anotsanangurwa neiyo yepamusoro layer, kusanganisira iyo basa parameter seti yeONU, mhando uye huwandu hwesevhisi yeT-CONT, iyo QoS paramita, ruzivo rwekumisikidza uye huwandu hwekuita, uye zivisa otomatiki zviitiko zvinomhanya zvesisitimu yekushandisa kumisikidzwa kweOLT kune ONT.Kutungamira kwekukanganisa kuongororwa, kuita uye kuchengetedza.
Mhedziso: GPON iri nani pane EPON
Batanidza layer encapsulation uye akawanda-sevhisi rutsigiro
Sezvinoratidzwa muMufananidzo 2, EPON inotevera Ethernet data format yakapfava, asi inowedzera 64-byte MPCP point-to-multipoint control protocol kune Ethernet header kuti iite bandwidth allocation, bandwidth round-robin, uye kuwanikwa otomatiki muEPON system.Range uye mamwe mabasa.Iko hakuna kutsvagisa kwakawanda parutsigiro rwesevhisi kunze kwesevhisi data (seTDM synchronization services).Vazhinji vatengesi veEPON vakagadzira zvimwe zvisiri-yakajairwa zvigadzirwa kugadzirisa dambudziko iri, asi hazvina kunaka uye zvakaoma kuzadzisa zvinodiwa mutakuri-kirasi QoS.
Mufananidzo 2: Kuenzaniswa kweGPON uye EPON protocol stacks
GPON yakavakirwa pane nyowani nyowani yekufambisa convergence (TC) layer, iyo inogona kupedzisa kuchinjika kwepamusoro-level diversity services.Sezvinoratidzwa mumufananidzo 2, inotsanangura ATM encapsulation uye GFP encapsulation (general framing protocol).Unogona kusarudza zvose.Imwe ndeye bhizinesi encapsulation.Tichifunga nezve mukurumbira wazvino weATM application, GPON inongotsigira GFP encapsulation inowanikwa.Iyo lite mudziyo yakatanga, ichibvisa ATM kubva kune protocol stack kuderedza mutengo.
GFP is a generic link layer process for multiple services, inotsanangurwa neITU seG. 7041. Nhamba shoma yekushandura yakagadzirwa kuGFP muGPON, uye PortID yakaunzwa pamusoro weGFP frame kuti itsigire multi-port multiplexing.A Frag (Chimedu) chikamu chechiratidzo chinounzwa zvakare kuti iwedzere inoshanda bandwidth yehurongwa.Uye inongotsigira iyo data yekugadzirisa modhi yekusiyana kureba data uye haitsigire iyo data yakajeka yekugadzirisa maitiro ezvidhinha data.GPON ine simba rekutakura mabasa akawanda.GPON's TC layer inonyanya kuenderana, uchishandisa yakajairwa 8 kHz (125μm) mafuremu akareba, ayo anobvumira GPON kutsigira nguva yekupedzisira-kusvika-kumagumo uye mamwe masevhisi e-quasi-synchronous, kunyanya kutsigira zvakananga TDM masevhisi, anonzi NativeTDM.GPON ine "zvakasikwa" tsigiro yeTDM masevhisi.
Mhedziso iyi: Iyo TC layer inotsigira GPON yeakawanda-sevhisi yakasimba kupfuura MPCP yeEPON.
Mhedziso
EPON neGPON vane zvazvakanakira.GPON iri nani pane EPON maererano nezviratidzo zvekushanda.Nekudaro, EPON ine mukana wenguva uye mutengo.GPON iri kubata.Kutarisira remangwana Broadband yekuwana musika inogona kunge isiri yekutsiva, inofanirwa kuwirirana.Kune bandwidth, akawanda-sevhisi, yakakwirira QoS uye chengetedzo zvinodiwa, uye tekinoroji yeATM semutengi wemusana, GPON ichave yakakodzera.Kune vatengi vane mutengo wakaderera wekunzwa, QoS uye kuchengetedza zvinodiwa, EPON yave chinhu chikuru.