Yini i-PON?Ubuchwepheshe bokufinyelela ku-Broadband buyadlondlobala, futhi bumiselwe ukuba inkundla yempi lapho intuthu ingasoze yashabalala.Njengamanje, umkhakha wasekhaya usewubuchwepheshe be-ADSL, kodwa abakhiqizi bemishini abaningi ngokwengeziwe kanye nabaqhubi baphendule ukunaka kwabo kubuchwepheshe bokufinyelela kwenethiwekhi ye-optical.
Izintengo zethusi ziyaqhubeka nokukhuphuka, amanani entengo ekhebula ayaqhubeka nokwehla, futhi isidingo esikhulayo se-IPTV nezinsizakalo zegeyimu yevidiyo kuqhuba ukukhula kwe-FTTH.Ithemba elihle lokushintsha intambo yethusi nentambo ye-coaxial enentambo ngentambo yokubona, ucingo, i-cable TV, kanye nokudlala kathathu kwedatha ye-broadband.
Umfanekiso 1: I-PON topology
Inethiwekhi ye-PON (Passive Optical Network) iwubuchwepheshe obuyinhloko bokubona i-FTTH fiber ekhaya, ihlinzeka ngokufinyelela i-fiber point-to-multipoint, njengoba kukhonjisiwe kuMfanekiso 1, iyi-OLT (itheminali yomugqa wokukhanya) kanye nohlangothi lomsebenzisi uhlangothi lwehhovisi.I-ONU (Optical Network Unit) kanye ne-ODN (Optical Distribution Network) zakhiwe.Ngokujwayelekile, i-downlink isebenzisa imodi yokusakaza ye-TDM bese i-uplink ithatha imodi ye-TDMA (Time Division Multiple Access) ukuze kwakheke i-topology yesihlahla sephoyinti kuya kumaphuzu amaningi. .Okugqama kakhulu kwe-PON njengobuchwepheshe bokufinyelela okubonakalayo “ukwenza okuthile”.I-ODN ayinazo izisetshenziswa zikagesi ezisebenzayo kanye nempahla yamandla kagesi.Zonke zakhiwe izingxenye ze-passive ezifana nezihlukanisi, ezinezindleko eziphansi zokuphatha nokusebenza.
Umlando Wokuthuthukiswa Kwe-PON
Ucwaningo lobuchwepheshe be-PON lwaqala ngo-1995. Ngo-Okthoba 1998, i-ITU yamukela izinga lobuchwepheshe be-PON elisekelwe ku-ATM, G, eligqugquzelwa inhlangano ye-FSAN (inethiwekhi yokufinyelela isevisi egcwele).983. Eyaziwa nangokuthi i-BPON (BroadbandPON).Izinga lingu-155Mbps futhi lingasekela ngokuzikhethela i-622Mbps.
I-EFMA (i-Ethernetin the First Mile Alliance) yethula umqondo we-Ethernet-PON (EPON) ekupheleni kuka-2000 ngezinga lokudlulisela elingu-1 Gbps kanye nesendlalelo sokuxhumanisa esisekelwe ku-Ethernet encapsulation elula.
I-GPON (Gigabit-CapablePON) yahlongozwa yinhlangano ye-FSAN ngoSepthemba 2002, futhi i-ITU yamukela i-G ngoMashi 2003. 984. 1 kanye ne-G. 984. 2 isivumelwano.G. 984.1 Izimpawu eziphelele zesistimu yokufinyelela ye-GPON zicacisiwe.G.984. 2 icacisa isendlalelo esingaphansi esihlobene nokusatshalaliswa ngokomzimba kwe-ODN (Optical Distribution Network) ye-GPON.NgoJuni 2004, i-ITU yadlula ku-G futhi.984. 3, ecacisa izidingo zesendlalelo se-Transmission Convergence (TC).
Ukuqhathaniswa kwemikhiqizo ye-EPON ne-GPON
I-EPON ne-GPON amalungu amabili ayinhloko okufinyelela kwenethiwekhi ye-optical, ngayinye inokufaneleka kwayo, ukuncintisana, ukuphelelisana nokufunda komunye nomunye.Okulandelayo kuziqhathanisa ezicini ezihlukahlukene:
Linganisa
I-EPON ihlinzeka ngokuxhumanisa okugxilile nokwehla kwe-1.25Gbps, isebenzisa umugqa wekhodi ongu-8b/10b, futhi izinga langempela ngu-1Gbps.
I-GPON isekela amamaki esivinini amaningi futhi ingasekela izivinini ze-asymmetric ezikhuphukayo neziphansi, 2.5Gbps noma 1.25Gbps ezansi nomfula, kanye ne-1.25Gbps noma 622Mbps uplink.Ngokwesidingo sangempela, amanani e-uplink ne-downlink ayanqunywa, futhi amamojula ahambisanayo optical akhethiwe ukuze kukhuliswe isilinganiso senani lentengo yedivayisi ebonakalayo.
Lesi siphetho: I-GPON ingcono kune-EPON.
Isilinganiso sokuhlukaniswa
Isilinganiso sokuhlukaniswa ukuthi bangaki ama-ONU (abasebenzisi) athwalwa imbobo eyodwa ye-OLT (ihhovisi).
Izinga le-EPON lichaza isilinganiso sokuhlukaniswa esingu-1:32.
Izinga le-GPON lichaza isilinganiso sokuhlukaniswa kokulandelayo 1:32;1:64;1:128
Eqinisweni, izinhlelo ze-EPON zobuchwepheshe nazo zingafinyelela izilinganiso eziphakeme zokuhlukaniswa, ezifana no-1:64, 1:128, iphrothokholi yokulawula ye-EPON ingasekela ama-ONU amaningi.Isilinganiso somgwaqo sinqunyelwe ikakhulukazi ukucaciswa kokusebenza kwemojula yokubona, kanye nokuhlukaniswa okukhulu. isilinganiso sizokwenza ukuthi izindleko zemojula ye-optical zikhuphuke kakhulu.Ngaphezu kwalokho, ukulahlekelwa kokufaka i-PON kungu-15 kuya ku-18 dB, futhi isilinganiso esikhulu sokuhlukaniswa sinciphisa ibanga lokudlulisela.Umkhawulokudonsa wokwabelana wabasebenzisi omningi kakhulu uyizindleko zesilinganiso esikhulu sokuhlukaniswa.
Lesi siphetho: I-GPON inikeza ukukhetha okuningi, kodwa ukucatshangelwa kwezindleko akubonakali.Ubukhulu bebanga lomzimba elingasekelwa uhlelo lwe-GPON.Uma isilinganiso sokuhlukaniswa kwe-optical singu-1:16, ibanga eliphezulu lomzimba elingu-20km kufanele lisekelwe.Uma isilinganiso sokuhlukaniswa kwe-optical singu-1:32, ibanga eliphezulu lomzimba elingu-10km kufanele lisekelwe.I-EPON iyefana,lesi siphetho: kuyalingana.
I-QOS(Ikhwalithi Yesevisi)
I-EPON yengeza i-MPCP engamabhayithi angu-64(iphrothokholi yokulawula amaphuzu amaningi) kusihloko se-Ethernet sikanhlokweni we-MAC. I-MPCP ilawula ukufinyelela ku-P2MP iphuzu kuya ku-multipoint topology ngemilayezo, imishini yesifunda, nezibali-sikhathi ukuze kusetshenziswe ukwabiwa komkhawulokudonsa oguqukayo we-DBA. I-MPCP ibandakanya ukwabiwa kwezikhala zesikhathi sokudluliswa kwe-ONU, ukutholakala okuzenzakalelayo kanye nokujoyina ama-ONU, kanye nokubika ngokuminyana ezandlalweni eziphakeme ukuze kwabelwe ngamandla umkhawulokudonsa.MPCP inikeza ukusekelwa okuyisisekelo kwe-topology ye-P2MP.Kodwa-ke, umthetho olandelwayo awuzihlukanisi izinto ezibalulekile zesevisi.Zonke izinsiza ziqhudelana ngokungahleliwe kumkhawulokudonsa.I-GPON ine-DBA ephelele kanye nekhono elihle kakhulu lesevisi ye-QoS.
I-GPON ihlukanisa indlela yokwabiwa komkhawulokudonsa wesevisi ibe izinhlobo ezine.Okubalulekile okuphezulu kulungisiwe (Kulungisiwe), Kuqinisekisiwe, Okungaqinisekisiwe, kanye Nomzamo Ongcono Kakhulu.I-DBA iphinde ichaze isiqukathi sethrafikhi (T-CONT) njengeyunithi yokushejula i-uplink, futhi i-T-CONT ngayinye ikhonjwa nge-Alloc-ID.I-T-CONT ngayinye ingaba ne-GEMPort-ID eyodwa noma ngaphezulu.I-T-CONT ihlukaniswe yaba izinhlobo ezinhlanu zamasevisi.Izinhlobo ezahlukene ze-T-CONTs zinezinhlobo ezahlukene zokwabiwa komkhawulokudonsa, ezingahlangabezana nezidingo ezihlukene ze-QoS zokugeleza kwesevisi okuhlukile kokulibaziseka, i-jitter, kanye nezinga lokulahlekelwa kwephakethe.Uhlobo loku-1 lwe-T-CONT lubonakala ngesikhala sesikhathi esimisiwe somkhawulokudonsa, esihambisana isabelo se-fixed-bandwidth (Fixed), esilungele izinsizakalo ezizwelayo ukubambezeleka, njengezinsizakalo zezwi.Uhlobo 2 lubonakala ngomkhawulokudonsa ogxilile kodwa i-slot yesikhathi esinqunyiwe.Isabelo somkhawulokudonsa oqinisekisiwe (Oqinisekisiwe) ohambisanayo sifanele izinsizakalo zomkhawulokudonsa ogxilile ezingadingi i-jitter ephezulu, njengezinsizakalo zevidiyo lapho kudingeka khona.Uhlobo lwesi-3 lubonakala ngesiqinisekiso esincane somkhawulokudonsa kanye nokwabelana okuguquguqukayo komkhawulokudonsa omningi, futhi linomkhawulo womkhawulokudonsa omkhulu, ohambisana nesabelo somkhawulokudonsa ongaqinisekisiwe (Ongaqinisekisiwe), ofanele izinsizakalo ezinezidingo zokuqinisekisa isevisi kanye nethrafikhi yokuqhuma okukhulu.Okufana nokudawuniloda ibhizinisi.Uhlobo lwesi-4 lubonakala nge-BestEffort, akukho siqinisekiso somkhawulokudonsa, esilungele izinsizakalo ezinezimfuneko eziphansi ze-latency kanye ne-jitter, njengesevisi ye-WEB yokuphequlula.Uhlobo lwesi-5 wuhlobo oluyinhlanganisela, ngemva kokwaba umkhawulokudonsa oqinisekisiwe nongaqinisekisiwe, owengeziwe Izidingo zomkhawulokudonsa zabiwa kahle kakhulu ngangokunokwenzeka.
Isiphetho: I-GPON ingcono kune-EPON
Sebenzisa futhi ulondoloze i-OAM
I-EPON ayinakho ukucatshangelwa okuningi kwe-OAM, kodwa ivele ichaze inkomba yephutha yerimothi ye-ONT, i-loopback nokuqapha kwesixhumanisi, futhi iwukusekela kokuzithandela.
I-GPON ichaza i-PLOAM (PhysicalLayerOAM) kusendlalelo esibonakalayo, futhi i-OMCI (ONTManagementandControlInterface) ichazwa kusendlalelo esingaphezulu ukuze yenze ukuphatha kwe-OAM kumaleveli amaningi.I-PLOAM isetshenziselwa ukusebenzisa ukubethela kwedatha, ukutholwa kwesimo, nokuqapha amaphutha.Iphrothokholi yesiteshi se-OMCI isetshenziselwa ukuphatha izinsizakalo ezichazwe ungqimba olungaphezulu, okuhlanganisa isethi yepharamitha yokusebenza ye-ONU, uhlobo nenani lesevisi ye-T-CONT, amapharamitha we-QoS, ulwazi lokumisa isicelo kanye nezibalo zokusebenza, kanye yazisa ngokuzenzakalelayo imicimbi esebenzayo yesistimu ukuze iqalise ukucushwa kwe-OLT ku-ONT.Ukuphathwa kokuxilongwa kwephutha, ukusebenza nokuphepha.
Isiphetho: I-GPON ingcono kune-EPON
Xhuma i-encapsulation yesendlalelo kanye nokusekelwa kwezinsizakalo eziningi
Njengoba kuboniswe kuMfanekiso 2, i-EPON ilandela ifomethi yedatha ye-Ethernet elula, kodwa yengeza iphrothokholi yokulawula iphuzu le-MPCP engu-64-byte kusihloko se-Ethernet ukuze kusetshenziswe ukwabiwa komkhawulokudonsa, umkhawulokudonsa ojikelezayo, kanye nokutholakala okuzenzakalelayo ohlelweni lwe-EPON.Ukuhamba neminye imisebenzi.Alukho ucwaningo oluningi ekusekelweni kwezinsizakalo ngaphandle kwamasevisi edatha (njengamasevisi okuvumelanisa e-TDM).Abathengisi abaningi be-EPON benze imikhiqizo engeyona ejwayelekile ukuze baxazulule le nkinga, kodwa ayilungile futhi kunzima ukuhlangabezana nezidingo ze-QoS zenkampani yenethiwekhi.
Umfanekiso 2: Ukuqhathaniswa kwezitaki zephrothokholi ye-GPON ne-EPON
I-GPON isekelwe kungqimba olusha ngokuphelele lwe-transport convergence (TC), olungaqedela ukulungiswa kwezinsizakalo ezisezingeni eliphezulu.Njengoba kukhonjisiwe kuMfanekiso 2, ichaza i-ATM encapsulation kanye ne-GFP encapsulation (iphrothokholi yozimele evamile).Ungakhetha kokubili.Enye ngeyokuhlanganisa ibhizinisi.Ngokubuka ukuthandwa kwamanje kwezicelo ze-ATM, i-GPON esekela kuphela i-GFP encapsulation iyatholakala.Idivayisi e-lite ibe khona, isusa i-ATM kusitaki sephrothokholi ukuze kwehliswe izindleko.
I-GFP iyinqubo yesendlalelo sesixhumanisi esijwayelekile sezinsizakalo eziningi, echazwa yi-ITU njenge-G. 7041.Inani elincane lokuguqulwa lenziwe ku-GFP ku-GPON, futhi i-PortID yethulwa enhlokweni yohlaka lwe-GFP ukuze isekele ukuphindaphindeka kwamachweba amaningi.Inkomba yokuhlukanisa i-Frag (Fragment) nayo yethulwa ukuze kwandiswe umkhawulokudonsa osebenzayo wohlelo.Futhi isekela kuphela imodi yokucubungula idatha yedatha yobude obuhlukahlukene futhi ayisekeli imodi yokucubungula ebonisa ngale idatha yamabhulokhi wedatha.I-GPON inamandla okuthwala izinsiza eziningi.Isendlalelo se-TC ye-GPON siyavumelana, sisebenzisa u-8 kHz ojwayelekile (125μm) amafreyimu anobude obungaguquki, avumela i-GPON ukuthi isekele isikhathi sokuphela-kuya-ekupheleni nezinye izinsizakalo ezilinganayo, ikakhulukazi zokusekela ngokuqondile izinsizakalo ze-TDM, okuthiwa i-NativeTDM.I-GPON inosekelo "lwemvelo" lwezinsizakalo ze-TDM.
Lesi siphetho: Isendlalelo se-TC esisekela i-GPON yezinsizakalo eziningi sinamandla kune-MPCP ye-EPON.
Isiphetho
I-EPON ne-GPON banezinzuzo zabo siqu.I-GPON ingcono kune-EPON ngokwezinkomba zokusebenza.Nokho, i-EPON inenzuzo yesikhathi nezindleko.I-GPON iyabamba.Ukubheka phambili emakethe yokufinyelela ye-broadband yesikhathi esizayo kungase kungabi indawo, kufanele kuhambisane.Ukuze uthole umkhawulokudonsa, izinsizakalo eziningi, i-QoS ephezulu kanye nezidingo zokuphepha, kanye nobuchwepheshe be-ATM njengekhasimende eliwumgogodla, i-GPON izofaneleka kakhulu.Kumakhasimende anokuzwela kwezindleko eziphansi, i-QoS nezidingo zokuphepha, i-EPON isiphenduke into ehamba phambili.