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 iphambili yokuqonda i-FTTH fiber ekhaya, ibonelela ngofikelelo lwefiber point-to-multipoint, njengoko kubonisiwe kuMfanekiso 1, yeyona nto.OLT(itheminali yomgca wokukhanya) kunye necala lomsebenzisi wecala leofisi. II-ONU(Iyunithi yeNethiwekhi ye-Optical Network) kunye ne-ODN (i-Optical Distribution Network) iqulunqwe. Ngokuqhelekileyo, i-downlink ithatha imo yosasazo ye-TDM kwaye i-uplink ithatha i-TDMA (i-Time Division Multiple Access) indlela yokwenza i-point-to-multipoint tree topology. Eyona nto ibalaseleyo ye-PON njengetekhnoloji yokufikelela kwi-optical "i-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 wokwahlula ukuba bangaphiIi-ONU(abasebenzisi) bathwalwa ngomnyeOLTizibuko (iofisi).
Umgangatho weEPON uchaza umlinganiselo wokwahlulwa kwe-1:32.
Umgangatho we-GPON uchaza umlinganiselo wokwahlula kwezi zilandelayo 1:32; 1:64; 1:128
Ngapha koko, iinkqubo zobugcisa ze-EPON zinokufikelela kwireyishini ephezulu yokwahlula, efana ne-1:64, 1:128, i-EPON yokulawula iprotocol inokuxhasa ngakumbi.Ii-ONU.Umlinganiselo wendlela unqunyelwe ngokukodwa ngokucaciswa kokusebenza kwemodyuli ye-optical, kwaye umlinganiselo omkhulu wokwahlula uya kubangela ukuba iindleko zemodyuli ye-optical inyuke 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 ulwabiwo lweI-ONUiindawo zokubeka ixesha lokuthumela, ukufunyanwa okuzenzekelayo kunye nokujoyinaIi-ONU, kunye nokunika ingxelo yoxinaniso kwiileya eziphezulu zokwaba i-bandwidth.MPCP ibonelela ngenkxaso esisiseko ye-P2MP topology. 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 lubonakaliswe 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 yeOMCI isetyenziselwa ukulawula iinkonzo ezichazwe ngumaleko ongaphezulu, ukuquka iparameter yomsebenzi iseti yeI-ONU, uhlobo kunye nobungakanani benkonzo ye-T-CONT, iiparamitha zeQoS, ulwazi loqwalaselo lwesicelo kunye neenkcukacha zokusebenza, kwaye ngokuzenzekelayo ukwazisa iziganeko ezisebenzayo zenkqubo ukuphumeza uqwalaselo lweOLTukuya 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.