Yintoni iPON?Itekhnoloji yokufikelela kwi-Broadband iya isanda, kwaye imiselwe ukuba ibe libala ledabi apho umsi ungasoze uphele.Okwangoku, i-mainstream yasekhaya iseyitekhnoloji ye-ADSL, kodwa ngakumbi nangakumbi abavelisi bezixhobo kunye nabaqhubi baye bajika ingqalelo yabo kwitekhnoloji yokufikelela kwinethiwekhi ye-optical network.
Amaxabiso eCopper ayaqhubeka nokunyuka, amaxabiso ekhebula ayaqhubeka nokuhla, kwaye imfuno ekhulayo ye-IPTV kunye neenkonzo zemidlalo yevidiyo iqhuba ukukhula kweFTTH.Ithemba elihle lokutshintsha intambo yobhedu kunye nentambo ye-coaxial enentambo ngentambo yokukhanya, umnxeba, i-TV yentambo, kunye nedatha ye-broadband yokudlala kathathu iyacaca.
Umzobo 1: I-PON topology
I-PON (inethiwekhi ye-Passive Optical Network) yeyona teknoloji ingundoqo yokuqonda i-FTTH ifayibha ekhaya, inika ufikelelo lwefiber point-to-multipoint, njengoko kubonisiwe kuMfanekiso 1, yiOLT (i-terminal yomgca wokukhanya) kunye necala lomsebenzisi icala ofisi.I-ONU (i-Optical Network Unit) kunye ne-ODN (i-Optical Distribution Network) iqulunqwe. Ngokuqhelekileyo, i-downlink ithatha imo yosasazo ye-TDM kunye ne-uplink ithatha i-TDMA (i-Time Division Multiple Access) indlela yokwenza i-point-to-multipoint tree topology. .Eyona nto ibalaseleyo yePON njengobuchwephesha bokufikelela kwi-optical “passive”.I-ODN ayiqulathanga naziphi na izixhobo zombane ezisebenzayo kunye nonikezelo lwamandla ombane.Zonke ziqulunqwe ngamacandelo e-passive afana ne-splitters, ezinolawulo oluphantsi kunye neendleko zokusebenza.
Imbali yoPhuhliso lwePON
Uphando lweteknoloji ye-PON lwaqala ngo-1995. Ngo-Oktobha 1998, i-ITU yamkele umgangatho we-PON wobugcisa obusekelwe kwi-ATM, G, ekhuthazwa ngumbutho we-FSAN (inethiwekhi yokufikelela kwinkonzo epheleleyo).983. Ikwabizwa ngokuba yi-BPON (BroadbandPON).Ireyithi yi-155Mbps kwaye inokuxhasa ngokuzithandela i-622Mbps.
I-EFMA (i-Ethernetin kwi-First Mile Alliance) yazisa ingcamango ye-Ethernet-PON (EPON) ekupheleni kwe-2000 kunye nezinga lokudluliselwa kwe-1 Gbps kunye noluhlu lwekhonkco olusekelwe kwi-encapsulation elula ye-Ethernet.
I-GPON (i-Gigabit-CapablePON) yaphakanyiswa ngumbutho we-FSAN ngoSeptemba 2002, kwaye i-ITU yamkela i-G ngo-Matshi 2003. 984. 1 kunye ne-G. 984. Isivumelwano se-2.G. 984.1 Iimpawu zizonke zenkqubo yofikelelo yeGPON zichaziwe.G.984. I-2 icacisa ukuhanjiswa okubonakalayo okunxulumene ne-sublayer ye-ODN (i-Optical Distribution Network) ye-GPON.NgoJuni ka-2004, i-ITU iphumelele i-G kwakhona.984. 3, echaza iimfuno zoMaleko woThutho lwe-Convergence (TC).
Ukuthelekiswa kwe-EPON kunye neemveliso ze-GPON
I-EPON kunye ne-GPON ngamalungu amabini aphambili okufikelela kwinethiwekhi ye-optical, nganye ineemfanelo zayo, ezikhuphisanayo, ezincedisana kunye nokufunda komnye nomnye.Oku kulandelayo kuyabathelekisa kwiinkalo ezahlukeneyo:
Ixabiso
I-EPON inikezela nge-uplink esisigxina kunye ne-downlink ye-1.25Gbps, usebenzisa i-8b / 10b ikhowudi yomgca, kunye nesantya sangempela yi-1Gbps.
I-GPON isekela amabakala amaninzi esantya kwaye inokuxhasa i-uplink kunye ne-downlink i-asymmetric speeds, i-2.5Gbps okanye i-1.25Gbps ezantsi, kunye ne-1.25Gbps okanye i-622Mbps uplink.Ngokweemfuno zangempela, i-uplink kunye ne-downlink rates inqunywe, kwaye iimodyuli ezihambelanayo ze-optical zikhethwa ukunyusa umlinganiselo wexabiso lexabiso le-optical device.
Esi sigqibo: I-GPON ingcono kune-EPON.
Ukwahlula umlinganiselo
Umlinganiselo wokwahlulwa kukuba zingaphi ii-ONU (abasebenzisi) ezithwalwa lizibuko elinye le-OLT (iofisi).
Umgangatho weEPON uchaza umlinganiselo wokwahlulwa kwe-1:32.
Umgangatho we-GPON uchaza umlinganiselo wokwahlula kwezi zilandelayo 1:32;1:64;1:128
Enyanisweni, iinkqubo ze-EPON zobugcisa zinokufikelela kwimilinganiselo ephezulu yokwahlula, njenge-1: 64, 1:128, i-EPON yokulawula iprotocol inokuxhasa ii-ONU ezininzi. umlinganiselo uya kubangela ukuba ixabiso lemodyuli ye-optical linyuke kakhulu.Ukongezelela, ilahleko yokufaka i-PON yi-15 ukuya kwi-18 dB, kwaye umlinganiselo omkhulu wokwahlula unciphisa umgama wokuhambisa.I-bandwidth enkulu yokwabelana ngabasebenzisi ikwayindleko yomlinganiselo omkhulu wokwahlula.
Esi sigqibo: I-GPON inikeza ukhetho oluninzi, kodwa ukuqwalaselwa kweendleko akubonakali.Owona mgama mkhulu womzimba onokuwuxhaswa yi-GPON system.Xa umlinganiselo we-optical split u-1:16, umgama ophezulu womzimba we-20km kufuneka uxhaswe.Xa i-optical split ratio iyi-1:32, umgama omde womzimba we-10km kufuneka uxhaswe.I-EPON iyafana,esi sigqibo: kuyalingana.
QOS(Umgangatho weNkonzo)
I-EPON yongeza i-MPCP ye-64-byte (iprotocol yokulawula amanqaku amaninzi) kwi-MAC header Ethernet header.MPCP ilawula ukufikelela kwi-P2MP point-to-multipoint topology ngemiyalezo, oomatshini bombuso, kunye nezibali-xesha ukuphumeza ulwabiwo lwe-DBA dynamic bandwidth.I-MPCP ibandakanya Ukwabiwa kwexesha losasazo lwe-ONU, ukufunyanwa okuzenzekelayo kunye nokudityaniswa kwee-ONU, kunye nokunika ingxelo yengxinano ukuya kumaleko aphezulu ukwaba ngokuguquguqukayo i-bandwidth.MPCP ibonelela ngenkxaso esisiseko kwi-topology ye-P2MP.Nangona kunjalo, iprotocol ayihluli izinto eziphambili zenkonzo.Zonke iinkonzo zikhuphisana ngokungenamkhethe kwi-bandwidth.I-GPON ine-DBA epheleleyo kunye neenkonzo ezibalaseleyo zeQoS.
I-GPON yohlula indlela yokwabiwa kwe-bandwidth yenkonzo ibe ziindidi ezine.Eyona nto iphambili ilungisiwe (Fixed), iQinisekile, ayiQinisekanga, kunye neBestEffort.I-DBA ichaza ngakumbi i-traffic container (T-CONT) njengeyunithi yokucwangcisa i-uplink traffic, kwaye i-T-CONT nganye ichongiwe nge-Alloc-ID.I-T-CONT nganye inokuqulatha enye okanye ngaphezulu kwe-GEMPort-ID.T-CONT yahlulwe yaba ziindidi ezintlanu zeenkonzo.Iindidi ezahlukeneyo ze-T-CONT zineendlela ezahlukeneyo zokwabiwa kwe-bandwidth, ezinokuhlangabezana neemfuno ze-QoS ezahlukeneyo zokuhamba kwenkonzo yokulibaziseka, i-jitter, kunye ne-packet loss rate. i-fixed-bandwidth (Fixed) yolwabiwo, efanelekileyo kwiinkonzo zokulibaziseka, ezifana neenkonzo zelizwi.Uhlobo lwe-2 lubonakaliswe yi-bandwidth esisigxina kodwa i-slot yexesha elingapheliyo.I-bandwidth eqinisekisiweyo ehambelanayo (eqinisekisiweyo) ifanelekile kwiinkonzo ze-bandwidth ezisisigxina ezingadingi i-jitter ephezulu, njengevidiyo kwiinkonzo zemfuno.Uhlobo lwe-3 lubonakaliswe ngesiqinisekiso esincinci se-bandwidth kunye nokwabelana ngokuguquguqukayo kwe-bandwidth engapheliyo, kwaye inomthintelo we-bandwidth ephezulu, ehambelana nokunikezelwa kwe-bandwidth engaqinisekanga (engaQinisekanga), ezifanelekileyo kwiinkonzo ezineemfuno zokuqinisekisa ngenkonzo kunye netrafikhi yokuqhuma okukhulu.Njengokukhuphela ishishini.Udidi lwe-4 lubonakaliswa ngu-BestEffort, akukho siqinisekiso se-bandwidth, esifanelekileyo kwiinkonzo ezine-latency ephantsi kunye neemfuno ze-jitter, ezifana nenkonzo yokukhangela i-WEB.Uhlobo lwe-5 luhlobo oludibeneyo, emva kokunikezelwa kwe-bandwidth eqinisekisiweyo kunye ne-non-guaranteed, ezongezelelweyo Iimfuno ze-bandwidth zinikezelwa ngokusemandleni.
Isiphelo: I-GPON ingcono kune-EPON
Sebenza kwaye ugcine i-OAM
I-EPON ayinangqwalaselo eninzi kakhulu ye-OAM, kodwa ichaza ngokulula i-ONT isalathiso sesiphoso esikude, i-loopback kunye nokujongwa kwekhonkco, kwaye iyinkxaso yokuzikhethela.
I-GPON ichaza i-PLOAM (i-PhysicalLayerOAM) kwinqanaba lomzimba, kunye ne-OMCI (i-ONTMagementandControlInterface) ichazwa kwinqanaba eliphezulu ukwenza ulawulo lwe-OAM kumanqanaba amaninzi.I-PLOAM isetyenziselwa ukuphumeza ukubethelwa kwedatha, ukufumanisa isimo, kunye nokujonga iphutha.Iprothokholi yetshaneli ye-OMCI isetyenziselwa ukulawula iinkonzo ezichazwe ngumaleko ongaphezulu, kuquka iparameter yomsebenzi iseti ye ONU, uhlobo kunye nobungakanani benkonzo ye-T-CONT, iparamitha zeQoS, ulwazi loqwalaselo lwesicelo kunye neenkcukacha zokusebenza, kunye ukwazisa ngokuzenzekelayo iziganeko ezisebenzayo zenkqubo ukuphumeza uqwalaselo lwe OLT ukuya kwi ONT.Ukulawulwa kokuxilongwa kwempazamo, ukusebenza kunye nokhuseleko.
Isiphelo: I-GPON ingcono kune-EPON
Ukufakwa kwe-link layer kunye nenkxaso yeenkonzo ezininzi
Njengoko kuboniswe kwi-Figure 2, i-EPON ilandela ifomathi yedatha ye-Ethernet elula, kodwa yongeza i-protocol ye-MPCP ye-64-byte point-to-multipoint kwi-header ye-Ethernet ukuphumeza ulwabiwo lwe-bandwidth, i-bandwidth round-robin, kunye nokufumanisa ngokuzenzekelayo kwinkqubo ye-EPON.Ukuhamba kunye neminye imisebenzi.Akukho uphando oluninzi malunga nenkxaso yeenkonzo ngaphandle kweenkonzo zedatha (ezifana neenkonzo zokuvumelanisa i-TDM).Abathengisi abaninzi be-EPON baye baphuhlisa iimveliso ezingezizo ezisemgangathweni ukusombulula le ngxaki, kodwa ayilunganga kwaye kunzima ukuhlangabezana neemfuno zomthwali we-QoS.
Umzobo 2: Ukuthelekiswa kwe-GPON kunye ne-EPON protocol stacks
I-GPON isekelwe kuluhlu olutsha ngokupheleleyo lwezothutho lwe-convergence (TC), olunokuthi lugqibe ukulungelelaniswa kweenkonzo eziphezulu zokwahluka.Njengoko kuboniswe kwi-Figure 2, ichaza i-ATM encapsulation kunye ne-GFP encapsulation (i-protocol yokuqulunqa ngokubanzi).Unokukhetha zombini.Enye yeyokubethelwa kweshishini.Ngokujonga ukuthandwa kwangoku kwezicelo ze-ATM, i-GPON exhasa kuphela i-GFP encapsulation iyafumaneka.Isixhobo se-lite savela, sisusa i-ATM kwi-protocol stack ukunciphisa iindleko.
I-GFP yinkqubo ye-generic link layer yeenkonzo ezininzi, ezichazwe yi-ITU njenge-G. 7041. Inani elincinci lokuguqulwa lenziwe kwi-GFP kwi-GPON, kwaye i-PortID yaziswa kwintloko yesakhelo se-GFP ukuxhasa i-multi-port multiplexing.Isalathiso sokwahlulwa kweFrag (Isiqhekeza) sikwaziswa ukunyusa umda osebenzayo wenkqubo.Kwaye ixhasa kuphela imo yokusetyenzwa kwedatha yedatha yobude obuguquguqukayo kwaye ayixhasi imowudi yokusetyenzwa elubala kwedatha yeebhloko zedatha.I-GPON inamandla okuthwala iinkonzo ezininzi.I-GPON's TC layer ihambelana ngokuyimfuneko, isebenzisa umgangatho we-8 kHz (125μm) izakhelo ezisisigxina, ezivumela i-GPON ukuba ixhase ixesha lokuphela kokuphela kunye nezinye iinkonzo ze-quasi-synchronous, ngokukodwa ukuxhasa ngokuthe ngqo iinkonzo ze-TDM, ebizwa ngokuba yiNativeTDM.I-GPON inenkxaso "yendalo" yeenkonzo ze-TDM.
Esi sigqibo: Umaleko we-TC oxhasa i-GPON kwiinkonzo ezininzi zomelele kuneMPCP ye-EPON.
Ukuqukumbela
I-EPON kunye ne-GPON zineenzuzo zazo.I-GPON ingcono kune-EPON ngokwezikhombisi zokusebenza.Nangona kunjalo, i-EPON inenzuzo yexesha kunye neendleko.I-GPON iyabamba.Ukujonga phambili kwimakethi yokufikelela kwibroadband yexesha elizayo isenokungabi yithathela indawo, kufuneka ibe yinkxaso.Kwi-bandwidth, i-multi-service, i-QoS ephezulu kunye neemfuno zokhuseleko, kunye nobuchwepheshe be-ATM njengomthengi we-backbone, i-GPON iya kufaneleka ngakumbi.Kubathengi abanovelwano lwexabiso eliphantsi, iQoS kunye neemfuno zokhuseleko, i-EPON ibe yeyona nto iphambili.