Ukuqaliswa kweenkqubo ezahlukeneyo zePON
1. Iteknoloji ye-APON
Phakathi kwiminyaka yee-1990, abanye abaqhubi benethiwekhi abakhulu baseka i-Full Service Access Network Alliance (FSAN), injongo yayo kukuqulunqa umgangatho odibeneyo wezixhobo ze-PON ukuze abenzi bezixhobo kunye nabaqhubi bangene kwimarike yezixhobo ze-PON kwaye bakhuphisane kunye. Isiphumo sokuqala kukucaciswa komgangatho we-PON ye-155Mbit / s kwi-ITU-T G.983 uluhlu lweengcebiso. Ngenxa yokuba i-ATM isetyenziswa njenge-protocol yomphathi, le nkqubo ibizwa ngokuba yi-APON system, kwaye isoloko ingaqondwa njengokubonelela ngeenkonzo ze-ATM kuphela. Ngoko ke, ibizwa ngokuba yi-Broadband Passive Optical Network (BPON) inkqubo yokubonisa ukuba le nkqubo inokubonelela ngeenkonzo ze-Ethernet Broadband ezifana nokufikelela kwinethiwekhi, ukuhanjiswa kwevidiyo, kunye nemigca yokuqeshisa ngesantya esiphezulu. Nangona kunjalo, kwesi sizukulwana seenkqubo zeFSAN, igama elisetyenziswa kakhulu yi-APON. Kamva, umgangatho we-APON uphuculwe, kwaye waqala ukuxhasa i-downlink 622 Mbit / s rates, kwaye iimpawu ezintsha zongezwa kwiindlela zokukhusela, ulwabiwo lwe-bandwidth (DBA), kunye nezinye iinkalo.
I-APON isebenzisa i-ATM njengeprotocol yomphathi. Ukuhanjiswa kwe-downstream yi-ATM eqhubekayo kunye nesantya esincinci se-155.52Mbit / s okanye i-622.08Mbit / s. Ulawulo olukhethekileyo lomsebenzi womzimba kunye nokugcinwa (PLOAM) iseli ifakwe kwi-data stream.Ukuhanjiswa kwe-Upstream ngamaseli e-ATM kwifomu yokuqhuma. Ukuze ufezekise ukugqithiswa kunye nokwamkelwa, i-3-byte overhead yomzimba yongezwa phambi kweseli nganye ye-53-byte. Ngomlinganiselo osisiseko we-155.52 Mbit / s, i-protocol yokudlulisa isekelwe kwi-downlink frame equkethe iiseli ze-ATM ze-56 (i-53 bytes ngeseli); xa i-bit rate inyuswe ukuya kwi-622.08 Mbit / s, ifreyim ye-downlink yandisiwe ukuya kwi-224 Cell. Kwinqanaba elisisiseko le-155.52 Mbit / s, ifomathi ye-uplink frame ngamaseli angama-53, iseli nganye i-56 bytes (i-53 ATM cell bytes plus 3 bytes overhead). Ukongeza kwiiseli zedatha ezingama-54 kwisakhelo se-downlink, kukho iiseli ezimbini ze-PLOAM, enye ekuqaleni kwesakhelo kwaye enye iphakathi kwesakhelo. Iseli nganye ye-PLOAM iqulethe ugunyaziso lokuhanjiswa kwe-uplink kwiseli ethile kwisakhelo esinyukayo (iiseli zefreyimu ezingama-53 eziPhezulu zinezibonelelo ze-53 ezifakwe kwiiseli ze-PLOAM) kunye nolwazi lwe-OAM & P. I-APON ibonelela ngezinto ezityebileyo nezipheleleyo ze-OAM, kubandakanya ukujonga impazamo encinci, ukothusa, ukufumanisa okuzenzekelayo, kunye nokukhangela okuzenzekelayo. Njengesixhobo sokhuseleko, inokukrazula kwaye ibethelele idatha yekhonkco ezantsi.
Ngokombono wokucubungula idatha, kwi-APON, idatha yomsebenzisi kufuneka ihanjiswe phantsi kokuguqulwa kweprotocol (AAL1 / 2 ye-TDM kunye ne-AAL5 yokuhanjiswa kwepakethe yedatha). Olu tshintsho lunzima ukulungelelanisa kwi-bandwidth ephezulu, kwaye izixhobo ezenza lo msebenzi zibandakanya ezinye izixhobo ezincedisayo ezinxulumene nazo, ezifana nememori yeseli, i-Glue Logic, njl., eyongeza kakhulu kwiindleko zenkqubo.
Ngoku, nokuba inethiwekhi engundoqo yothumelo lomgama omde okanye i-metropolitan area access network convergence layer, itekhnoloji yonxibelelwano lwedijithali ithe chu kancinci ukusuka kwi-ATM-centric ukuya kwi-IP-based ukubonelela ngevidiyo, iaudio, kunye nonxibelelwano lwedatha. Ngoko ke, kuphela isakhelo sothungelwano sokufikelela esinokuziqhelanisa nakokubini ukufikelela kwangoku kunye nobuchwepheshe obuphambili bothungelwano lwexesha elizayo lunokwenza ikamva lenethiwekhi ye-IP ibe yinyani.
I-APON iye yahoxiswa ngokuthe ngcembe kwimarike ngenxa yobunzima bayo kunye nokusebenza kakuhle kokuhanjiswa kwedatha.
2. EPON
Phantse ngexesha elifanayo kunye nenkqubo ye-APON, i-IEEE iphinde yaseka iqela lokuqala lophando lwe-Ethernet (EFM) ukuqalisa i-Ethernet-based EPON (i-Ethernet Passive Optical Network) ngokubhekiselele kwinethiwekhi yokufikelela kwifiber, ebonisa ithemba elihle lemarike. Iqela lokufunda leleqela le-IEEE 802.3 eliphuhlise umgangatho we-Ethernet. Ngokufanayo, umda wayo wophando ukhawulelwe kuyilo, kwaye kufuneka uhambelane ne-802.3 ekhoyo yolawulo lokufikelela kwimidiya (MAC) imisebenzi yomaleko. Ngo-Epreli 2004, iqela lophando lazisa umgangatho we-IEEE 802.3ah we-EPON, kunye ne-uplink kunye ne-downlink rate ye-1 Gbit / s (usebenzisa i-coding ye-8B / 10B, kunye nomgca we-1.25 Gbit / s), ukuphelisa abavelisi be-EPON ' ukusetyenziswa kweeprothokholi zabucala ukuphuhlisa umgangatho wesixhobo.
I-EPON yinkqubo yokufikelela kwi-broadband esekelwe kwi-teknoloji ye-Ethernet. Isebenzisa i-PON topology ukuphumeza ukufikelela kwe-Ethernet. Ubuchwephesha obuphambili bomaleko wekhonkco ledatha ikakhulu bubandakanya: iProtokholi yoLawulo lokuFikeleleka okuninzi (MPCP) yetshaneli ye-uplink, iplagi kunye nengxaki yokudlala yeI-ONU, ukusukela kunye nokulibaziseka kwembuyekezo yemigaqo yeOLT, kunye nemiba yokuhambelana kweprotocol.
Uluhlu lomzimba lwe-IEEE 802.3ah lubandakanya zombini i-point-to-point (P2P) i-fiber optical edibeneyo kunye neengcingo zobhedu, kunye neemeko zenethiwekhi ye-PON ye-point-to-multipoint (P2MP). Ukuze kuququzelelwe ukusebenza kwenethiwekhi kunye nokulungiswa kwempazamo, indlela ye-OAM nayo ifakiwe. Kwi-topology yenethiwekhi ye-P2MP, i-EPON isekwe kwindlela ebizwa ngokuba yi-Multipoint Control Protocol (MPCP), engumsebenzi ngaphakathi kwe-MAC sublayer. I-MPCP isebenzisa imiyalezo, oomatshini bombuso, kunye nezibali-xesha ukulawula ukufikelela kwi-topology yenethiwekhi ye-P2MP. Iyunithi nganye yenethiwekhi yamehlo (I-ONU) kwi-topology ye-P2MP yothungelwano ine-MPCP protocol ekhoyo enxibelelana ne-MPCP protocol ekhoyoOLT. .
Isiseko se-EPON / i-MPCP ye-protocol yi-point-to-point simulation sublayer, eyenza inethiwekhi ye-P2MP ibonakale njengengqokelela ye-P2P yekhonkco kwi-protocol layers ephezulu.
Ukuze kuncitshiswe iindleko zeI-ONU, itekhnoloji eziphambili ze-EPON umaleko womzimba zigxininiswe kwiOLT, kubandakanywa ukuvumelanisa ngokukhawuleza kwezibonakaliso ezigqabhukileyo, ukuvumelanisa kwenethiwekhi, ukulawula amandla kwiimodyuli ze-transceiver optical, kunye nokwamkelwa okuguquguqukayo.
I-EPON idibanisa iingenelo zePON kunye neemveliso zedatha ye-Ethernet ukwenza iinzuzo ezininzi ezizodwa. Inkqubo ye-EPON inokubonelela nge-uplink kunye ne-downlink bandwidths ukuya kwi-1 Gbit / s, enokuthi ihlangabezane neemfuno zabasebenzisi kwixesha elizayo ixesha elide. I-EPON isebenzisa itekhnoloji yokuphindaphinda ukuxhasa abasebenzisi abaninzi, kwaye umsebenzisi ngamnye unokonwabela i-bandwidth enkulu. Inkqubo ye-EPON ayisebenzisi izixhobo ze-ATM ezibizayo kunye nezixhobo ze-SONET, kwaye iyahambelana ne-Ethernet ekhoyo, ilula kakhulu isakhiwo senkqubo, ixabiso eliphantsi, kunye nokulula ukuphucula. Ngenxa yobomi obude bezixhobo ze-passive optical, iindleko zokugcinwa kwemigca yangaphandle ziyancipha kakhulu. Kwangaxeshanye, ujongano oluqhelekileyo lwe-Ethernet lunokuthatha ithuba lezixhobo ze-Ethernet ezikhoyo zexabiso eliphantsi kunye nokugcina iindleko. Ulwakhiwo lwePON ngokwalo lumisela ukuba uthungelwano lunokala kakhulu. Ngethuba nje isixhobo se-terminal sitshintshwa, inethiwekhi inokuphuculwa ukuya kwi-10 Gbit / s okanye ngaphezulu. I-EPON ayikwazi nje ukudibanisa i-cable cable ekhoyo, iinkonzo zedatha kunye nezwi, kodwa kwakhona ihambelane neenkonzo ezizayo ezifana ne-TV yedijithali, i-VoIP, i-conferencing yevidiyo kunye ne-VOD, njl., ukufezekisa ukufikelela kwinkonzo edibeneyo.
Ukusetyenziswa ngokubanzi komthwali we-EPON kunye nobunye ubugcisa bofikelelo kuqhubela phambili ukutyebisa izisombululo zobuchwepheshe bokufikelela kwibroadband.
Ukusebenzisa i-EPON kunokwenza i-DSL iphule umda wesiqhelo kwaye yandise ukhuseleko. Xa iI-ONUidityaniswe kwi-Digital Subscriber Line Access Multiplexer (DSLAM), uluhlu olufikelelekayo lwe-DSL kunye neqela lalo lomsebenzisi elinokwenzeka liya kwanda kakhulu.
Ngokufanayo, ngokudibanisa i-CMTS (iCable Modem Termination System) yeI-ONU, I-EPON inokubonelela nge-bandwidth kunxibelelwano lweCable ekhoyo, kwaye ivumele abaqhubi bekhebula ukuba baphumeze iinkonzo ezisebenzisanayo ngokwenene ngelixa benciphisa iindleko zokwakha kunye nokusebenza.
Kuzo zombini iimeko, abaqhubi banokwandisa isiseko sabo somsebenzisi ngokusekelwe kwisakhiwo senethiwekhi ekhoyo kunye notyalo-mali. I-EPON inokwandisa i-MSPP ye-point-to-point (i-Multiple Services Provisioning Platform) kunye ne-IP / Ethernet.
Ukongezelela, iteknoloji ye-EPON ingasetyenziselwa ukusombulula ingxaki yedatha ye-uplink yesikhululo sesiseko kwi-teknoloji yokufikelela kwi-wireless ehlanganiswe kwinethiwekhi engundoqo.
3.GPON
Kwi-2001, i-FSAN iqalise umzamo omtsha wokulinganisa iinethiwekhi ze-PON ezisebenza ngaphezu kwe-1 Gbit / s. Ukongeza ekuxhaseni amaxabiso aphezulu, yonke iprotocol ivuliwe ukuze iphinde icinge kwaye ifumane isisombululo esilungileyo kunye nesona sisebenzayo malunga nokuxhasa iinkonzo ezininzi, imisebenzi ye-OAM & P kunye ne-scalability. Njengenxalenye yomsebenzi we-GPON, i-FSAN yaqala ukuqokelela iimfuno zawo onke amalungu ayo (kubandakanywa nabaqhubi abakhulu emhlabeni wonke), ngoko ngokusekelwe kule nto, wabhala uxwebhu olubizwa ngokuba yi-Gigabit Service Requirements (GSR) kwaye yenza isincomo esisemthethweni ( G.GON. GSR) ukuya kwi-ITU-T. Iimfuno eziphambili zeGPON ezichazwe kwifayile yeGSR zezi zilandelayo.
l Ixhasa iinkonzo ezipheleleyo, kubandakanywa ilizwi (TDM, SONET / SDH), Ethernet (10/100 Base-T), i-ATM, imigca eqeshisayo, njl.
l Umgama okhoyo owenziweyo ubuncinci yi-20km, kwaye umgama osengqiqweni ulinganiselwe ukuya kuma-60km.
l Ixhasa imilinganiselo yebit eyahlukeneyo usebenzisa iprothokholi efanayo, kuquka i-symmetrical 622 Mbit / s, symmetrical 1.25 Gbit / s, ezantsi 2.5 Gbit / s kunye nomlambo onyukayo 1.25 Gbit / s, kunye nezinye iireyithi ze-bit.
l I-OAM & P imisebenzi enamandla enokubonelela ngolawulo lwenkonzo yokuphela kokuphela.
l Ngenxa yeempawu zokusasazwa kwe-PON, ukhuseleko lweenkonzo ze-downlink kufuneka ziqinisekiswe kwinqanaba leprotocol.
I-FSAN iphakamise ukuba uyilo lomgangatho we-GPON kufuneka luhlangabezane nezi njongo zilandelayo.
l Ulwakhiwo lwesakhelo lunokwandiswa ukusuka kwi-622Mbit / s ukuya kwi-2.5Gbit / s, kwaye ixhasa i-asymmetric bit rate.
l Isiqinisekiso sokusetyenziswa kwe-bandwidth ephezulu kunye nokusebenza okuphezulu kulo naliphi na ishishini.
l Faka nayiphi na inkonzo (i-TDM kunye nepakethe) kwisakhelo se-125ms nge-GFP.
l Usasazo olusebenzayo nolungenandleko lweenkonzo zeTDM ezisulungekileyo.
l Ulwabiwo lwebhanwidth eDynamic nganyeI-ONUngesalathisi se-bandwidth.
Ekubeni i-GPON iphinde yaqwalasela isicelo kunye neemfuno ze-PON ukusuka ezantsi ukuya phezulu, yabeka isiseko sesisombululo esitsha kwaye ayisekho kumgangatho we-APON wangaphambili, ngoko ke abanye abavelisi bayibiza ngokuba yi-PON yendalo (indlela yendalo ye-PON). Ngakolunye uhlangothi, i-GPON igcina imisebenzi emininzi engahambelani ngokuthe ngqo kwi-PON, njengemiyalezo ye-OAM, i-DBA, njl. Ngakolunye uhlangothi, i-GPON isekelwe kwi-TC entsha (convergence transmission) layer. I-GFP (inkqubo yokuqulunqa ngokubanzi) ekhethwe yi-FSAN yi-protocol esekelwe kwisakhelo esilungisa ulwazi lwenkonzo evela kubathengi abaphezulu benethiwekhi yezothutho ngokusebenzisa indlela eqhelekileyo. Uthungelwano lwezothutho lunokuba naluphi na uhlobo lwenethiwekhi, njenge-SONET / SDH kunye ne-ITU-T G.709 (OTN), njl. Ulwazi lomxhasi lunokuba yipakethe-based (njenge-IP / PPP, okt IP / Point to Point protocal , okanye i-Ethernet MAC izakhelo, njl. ), Inokuthi ibe yisantya sesantya esiqhubekayo okanye ezinye iintlobo zolwazi lweshishini. I-GFP imiselwe ngokusemthethweni njenge-ITU-T eqhelekileyo G.7041. Ngenxa yokuba i-GFP inikezela ngendlela esebenzayo kunye nelula yokuhambisa iinkonzo ezahlukeneyo kwinethiwekhi yokuhanjiswa kwe-synchronous, kulungele ukuyisebenzisa njengesiseko se-GPON TC layer. Ukongezelela, xa usebenzisa i-GFP, i-GPON TC ihambelana ngokuyimfuneko kwaye isebenzisa iifreyimu eziqhelekileyo ze-SONET / SDH 8kHz (125ms), eyenza i-GPON ixhase ngokuthe ngqo iinkonzo ze-TDM. Kumgangatho okhutshwe ngokusemthethweni we-G.984.3, isiphakamiso se-FSAN kwi-GFP njengoko iteknoloji yokulungelelanisa i-TC yamukelwa, kunye nokucubungula okwenziwe lula kwenziwa, okubizwa ngokuba yi-GPON encapsulation method (GEM, GPONEncapsulationMethod).
Ukusetyenziswa kwenkqubo ye-EPON
I-EPON, njengeteknoloji entsha yokufikelela kwi-broadband, yinkqubo yokubonelela ngenkonzo epheleleyo enokuxhasa iinkonzo zedatha kunye neenkonzo zexesha langempela ezifana nezwi kunye nevidiyo.
Uyilo lwendlela yokubona ye-EPON inokusebenzisa i-3 wavelengths. Ukuba awucingi ukuxhasa iinkonzo ze-CATV okanye ze-DWDM, i-wavelengths ezimbini zisetyenziswa ngokubanzi. Xa usebenzisa amaza amaza ama-3, i-wavelength enyukayo yi-1310nm, i-wavelength esezantsi yi-1490nm, kunye ne-1550nm eyongezelelweyo ye-wavelength iyongezwa. Ukunyuka kwe-1550nm wavelength kusetyenziselwa ukuhambisa ngokuthe ngqo imiqondiso yevidiyo ye-analog. Ngenxa yokuba isignali yevidiyo ye-analog yangoku isalawulwa yi-rediyo kunye neenkonzo zethelevishini, kuqikelelwa ukuba ayiyi kutshintshwa ngokupheleleyo kwiinkonzo zevidiyo zedijithali kude kube ngu-2015. Ngoko ke, inkqubo ye-EPON esele yenziwe ngoku kufuneka ixhase zombini iinkonzo zevidiyo zedijithali kunye neenkonzo zevidiyo ze-analog. I-1490nm yasekuqaleni isaphethe idatha ye-downlink, ividiyo yedijithali kunye neenkonzo zezwi, kwaye i-1310nm ihambisa izibonakaliso zezwi lomsebenzisi we-uplink, ividiyo yedijithali kwimfuno (VOD), kunye nokucela ulwazi lokukhuphela idatha.
Izibonakaliso zezwi zineemfuno eziqinileyo zokulibaziseka kunye ne-jitter, kwaye i-Ethernet ayinikezeli ukulibaziseka kwepakethi yokuphela kokuphela, izinga lokulahleka kwepakethi, kunye namandla okulawula i-bandwidth. Ngoko ke, indlela yokuqinisekisa umgangatho wenkonzo xa i-EPON iphakamisa iimpawu zelizwi yingxaki engxamisekileyo ukuba isonjululwe.
1. TDM ishishini
Okwangoku, eyona nto ithandabuzekayo ye-EPON yeenkonzo ezininzi zokukwazi ukuhambisa iinkonzo ze-TDM zemveli.
Iinkonzo ze-TDM ezikhankanywe apha ziquka iindidi ezimbini zeenkonzo zelizwi (i-POTS, iNkonzo yeFowuni edumileyo yakudala) kunye neenkonzo zesekethe (T1 / El, N´64kbit / s iintambo eziqeshiweyo).
Xa iinkqubo ze-EPON ziphethe iinkonzo zedatha ezinikezelweyo (2048kbit / s okanye 13´64kbit / s iinkonzo zedatha), i-TDM phezu kwe-Ethernet iyacetyiswa. Inkqubo ye-EPON inokwamkela ukutshintshwa kwesekethe okanye iVolP xa uphethe iinkonzo zelizwi.
Kwiminyaka embalwa ezayo, ngenxa yokuba imfuno yemarike yeenkonzo zesekethe isenkulu kakhulu, inkqubo yeEPON iyafuneka ukuba iphathe zombini ipakethe-itshintshiweiinkonzo kunye nesekethe-itshintshiweiinkonzo. I-EFM iyithwala njani i-TDM kwi-EPON kunye nendlela yokuqinisekisa umgangatho weenkonzo ze-TDM. Akukho malungiselelo athile kwithekhnoloji, kodwa kufuneka ahambelane nefomathi yesakhelo se-Ethernet. I-EPON yeenkonzo ezininzi (MS-EPON) ithatha iteknoloji ye-E1 Over Ethernet, eyisombulula ngokufanelekileyo ingxaki yokulungelelaniswa kweenkonzo ze-TDM kwiifreyimu ze-Ethernet, eyenza i-EPON iqonde ukuhanjiswa kweenkonzo ezininzi kunye nokufikelela. Kwangaxeshanye, iMS-EPON yoyisa umsantsa phakathiOLTkwayeI-ONU. Into ekwabelwana ngayo ingxabano ye-bandwidth inika abasebenzisi be-Ethernet isiqinisekiso esiqinisekisiweyo se-bandwidth.
Indlela ye-encapsulation ye-Ethernet yenza iteknoloji ye-EPON ifaneleke kakhulu ukuthwala iinkonzo ze-IP, kodwa iphinda ibhekane nengxaki enkulu-kunzima ukuthwala iinkonzo ze-TDM ezifana nedatha yezwi okanye yesiphaluka. I-EPON yi-Ethernet-based asynchronous transmission network. Ayinayo iwotshi echanekileyo ephezulu edityaniswe kwinethiwekhi yonke, kwaye kunzima ukuhlangabezana neemfuno zexesha kunye nongqamaniso lweenkonzo ze-TDM. Ukusombulula ingxaki yokuvumelanisa ixesha leenkonzo ze-TDM ngelixa uqinisekisa ubunzima bezobuchwepheshe obufana ne-QoS yeenkonzo ze-TDM, akufuneki siphucule kuphela uyilo lwenkqubo ye-EPON ngokwayo, kodwa kufuneka samkele iteknoloji ethile.
Isalathiso sokusebenza seseketheitshintshiweinkonzo yelizwi ibonisa ukuba xa inkqubo ye-EPON isebenzisa iseketheitshintshiweindlela yokuthwala iinkonzo zezwi, kufuneka ihlangabezane neemfuno ze-YDN 065-1997 "Inkcazo yoBugcisa ngokuBanzi kwiSixhobo soTshintsho lweMnxeba yeSebe lezoThutho kunye noNxibelelwano lwezoThutho" kunye ne-YD / T 1128-2001 "Izixhobo zoTshintsho zeFowuni Jikelele" IiNkcazo zoBugcisa (iSihlomelo 1 ) “iimfuno zesekethe esulungekileyoitshintshiweumgangatho welizwi. Ke ngoko, i-EPON okwangoku inezi ngxaki zilandelayo ngeenkonzo ze-TDM.
① Inkonzo ye-TDM isiqinisekiso seQoS: Nangona i-bandwidth ethathwe yinkonzo ye-TDM incinci, ineemfuno eziphezulu kwiimpawu ezifana nokulibaziseka, i-jitter, i-drift, kunye ne-bit error rate. Oku akufuni kuphela ukuqwalasela indlela yokunciphisa ukulibaziseka kokuhanjiswa kunye ne-jitter yenkonzo ye-TDM ngexesha lokwabiwa kwe-bandwidth ye-uplink, kodwa nokuqinisekisa ukuba inkonzo ye-TDM ilawula ngokungqongqo ukulibaziseka kunye ne-jitter kwisicwangciso sokulawula i-downlink bandwidth.
② Ixesha kunye nongqamaniso lweenkonzo ze-TDM: Iinkonzo ze-TDM zineemfuno ezingqongqo ngokukodwa kwixesha kunye nongqamaniso. I-EPON ngokusisiseko yinethiwekhi yothumelo esynchronous esekwe kubuchwephesha be-Ethernet. Akukho iwotshi yonxibelelwano ngefowuni echanekileyo ephezulu edityaniswe kuyo yonke inethiwekhi. Ukuchaneka kwewotshi echazwa yi-Ethernet yi ± 100′10 kunye nokuchaneka kwewotshi efunwa ziinkonzo zesiqhelo ze-TDM yi-± 50′10. Ukongeza, ngelixa unikezela ngewotshi yonxibelelwano ngefowuni edityaniswe kuyo yonke inethiwekhi, idatha ye-TDM kufuneka idluliselwe ngamaxesha athile ukuze ihlangabezane neemfuno zayo ze-jitter kunye neempazamo.
③ Ukusinda kwe-EPON: Inkonzo ye-TDM ikwafuna ukuba umnatha womthwali kufuneka ube nokuphila okulungileyo. Xa ukusilela okukhulu kwenzeka, inkonzo inokuthembeka ngokuthembekileyoitshintshiwengelona xesha lifutshane. Ngenxa yokuba i-EPON isetyenziselwa ukufikelela kulwakhiwo lwenethiwekhi, isondele kakhulu kubasebenzisi, kwaye izicelo ezahlukeneyo kunye neendawo zokusebenzisa zinzima. Ichaphazeleka ngokulula ngezinto ezingaziwayo ezifana nokwakhiwa kwedolophu, okubangela iingozi ezifana nokuphazamiseka kwekhonkco. Ngoko ke, inkqubo ye-EPON ifuneka ngokukhawuleza ukubonelela ngesisombululo sokukhusela inkqubo yeendleko.
2. Iinkonzo ze-IP
I-EPON idlulisela iipakethi zedatha ye-IP ngaphandle kokuguqulwa kweprotocol kwaye inokusebenza okuphezulu, efanelekileyo kakhulu kwiinkonzo zedatha.
Itekhnoloji ye-VolP, njengeteknoloji eshushu ekuphuhlisweni, ifezekise umlinganiselo othile wesicelo kwiminyaka yakutshanje, kwaye iyindlela esebenzayo yokuthwala iinkonzo zelizwi kwiinethiwekhi ze-IP. Kwinkqubo ye-EPON, kunokwenzeka kwakhona ukuphumeza ukufikelela kwiinkonzo zomnxeba zendabuko ngokongeza izixhobo ezithile zeVoIP okanye imisebenzi. Ukusebenzisa iteknoloji yeVoIP, nje ukuba ukulibaziseka kunye neempawu ze-jitter zenkonzo yezwi ye-EPON ziqinisekisiwe, eminye imisebenzi ishiywe kwisixhobo sokufikelela esihlangeneyo somsebenzisi (i-IAD, iDivaysi yokuFikelela eDityanisiweyo) kunye nesixhobo sokufikelela kwisango eliphakathi ukuze kuqhutywe inkonzo yezwi. Ugqithiso. Le ndlela ilula kakhulu ukuyiphumeza kwaye inokubukisa ngokuthe ngqo ubugcisa obukhoyo, kodwa ifuna izixhobo zokungena kwi-ofisi esembindini ezibizayo, iindleko zokwakhiwa kothungelwano eziphezulu, kwaye inqunyanyiswa ziziphene zetekhnoloji yeVoIP ngokwayo. Ukongeza, iinkonzo zedatha ye-E1 kunye ne-N64kbit / s ayinakubonelelwa.
Xa inkqubo ye-EPON isebenzisa i-VoIP ukuthwala iinkonzo zelizwi, kufuneka ihlangabezane nezi zalathisi zokusebenza ezilandelayo kwiinkonzo zezwi leVoIP.
① Ixesha lokutshintsha okuguquguqukayo lokukhowudwa kwelizwi lingaphantsi kwe-60ms.
② Kufuneka ibene-80ms yesakhono sokugcina isithinteli ukuze kuqinisekiswe ukuba akukho kucinywa kwentetho kunye namajita ayenzekayo.
③ Uvavanyo lwenjongo yelizwi: Xa iimeko zothungelwano zilungile, ixabiso eliqhelekileyo le-PSQM lingaphantsi kwe-1.5; xa iimeko zenethiwekhi zihluphekile (iipakethi ilahleko izinga = 1%, jitter = 20ms, ukulibaziseka = 100ms), ixabiso eliqhelekileyo le-PSQM ngu <1.8; Xa iimeko zimbi (iipakethi ilahleko izinga = 5%, jitter = 60ms, ukulibaziseka = 400ms), umyinge we-PSQM ungaphantsi kwe-2.0.
④ Uvavanyo lwentetho lwentetho: Xa iimeko zothungelwano zilungile, ixabiso eliphakathi kweMOS ngu> 4.0; xa iimeko zenethiwekhi zihluphekile (iipakethi ilahleko izinga = 1%, jitter = 20ms, ukulibaziseka = 100ms), ixabiso eliqhelekileyo leMOS ngu <3.5; inethiwekhi Xa iimeko zimbi (iipakethi ilahleko izinga = 5%, jitter = 60ms, ukulibaziseka = 400ms), ixabiso eliqhelekileyo leMOS <3.0.
⑤ Ireyithi yokufaka ikhowudi: G.711, ireyithi yokufaka ikhowudi = 64kbit / s. Kwi-G.729a, ireyithi yekhowudi efunekayo yi<18kbit / s. Kwi-G.723.1, ireyithi yekhowudi ye-G.723.1 (5.3) yi-<18kbit / s, kunye ne-G.723.1 (6.3) ireyithi yekhowudi <15kbit / s.
⑥ Isalathiso sokulibazisa (ukulibaziseka kwe-loopback): Ukulibaziseka kwe-VoIP kubandakanya ukulibaziseka kwe-codec, ukulibaziseka kwe-input buffer ekupheleni kokufumana, kunye nokulibaziseka komgca wangaphakathi. Xa kusetyenziswa i-encoding ye-G.729a, ukulibaziseka kwe-loopback yi-<150ms. Xa kusetyenziswa i-encoding ye-G.723.1, ukulibaziseka kwe-loopback yi-<200ms.
3.ishishini CATV
Kwiinkonzo ze-CATV ze-analog, i-EPON inokuthi iqhutywe ngendlela efanayo ne-GPON: yongeza i-wavelength (ngokwenene le yiteknoloji ye-WDM kwaye ayinanto yokwenza ne-EPON kunye ne-GPON ngokwayo).
Itekhnoloji ye-PON yeyona ndlela ilungileyo yokufikelela kwi-FTTx yokufikelela kwibroadband. I-EPON yiteknoloji entsha ye-optical access network eyenziwe ngokudibanisa iteknoloji ye-Ethernet kunye ne-PON iteknoloji. Ingasetyenziselwa ukuhambisa ilizwi, idatha kunye neenkonzo zevidiyo kwaye iyahambelana. Kwiinkonzo ezithile ezintsha kwixesha elizayo, i-EPON iya kuba yeyona teknoloji ibalaseleyo yenkonzo epheleleyo yokufikelela kwi-broadband optical kunye nezibonelelo zayo ezigqibeleleyo ezifana ne-bandwidth ephezulu, ukusebenza kakuhle, kunye nokwandiswa okulula.
Inkqubo yokukhusela yePON
Ukuze kuphuculwe ukuthembeka kwenethiwekhi kunye nokuphila, indlela yokutshintsha i-fiber yokukhusela ingasetyenziswa kwinkqubo ye-PON. Indlela yokutshintsha i-fiber optical inokwenziwa ngeendlela ezimbini: ① ukutshintshela ngokuzenzekelayo, okubangelwa kukubona iimpazamo; ② ukutshintshwa okunyanzeliswayo, okubangelwa ziziganeko zolawulo.
Kukho iintlobo ezintathu eziphambili zokhuseleko lwefayibha: ukukhuselwa kwe-backbone fiber redundancy,OLTUkukhuselwa kwe-PON kwi-port redundancy, kunye nokukhuselwa ngokupheleleyo, njengoko kubonisiwe kwi-Figure 1.16.
Ukukhuselwa kwe-backbone fiber redundancy (Umfanekiso 1.16 (a)): usebenzisa i-PON port enye kunye ne-1'2 optical eyakhelweyo.tshintshaeOLTIzibuko lePON; usebenzisa i-2: I-splitter ye-optical ayikho; iOLTibona ubume bomgca; Akukho mfuneko zikhethekileyo zeI-ONU.
OLTUkukhuselwa kwe-PON kwi-port redundancy (Umfanekiso 1.16 (b)): I-PON port yokulinda ikwimo ebandayo yokulinda, isebenzisa i-2: i-N splitter ebonakalayo; iOLTibona ubume bomgca, kwaye utshintsho lwenziwa yiOLT, ngaphandle kweemfuno ezizodwa zeI-ONU.
Ukhuseleko olupheleleyo (Umfanekiso 1.16 (c)): zombini izibuko ze-PON eziphambili kunye ne-backup zikwimeko yokusebenza; ezimbini 2: Akukho ziqhekeza zamehlo ezisetyenzisiweyo; i-opticaltshintshayakhiwe phambi kweI-ONUI-PON port, kunye neI-ONUibona ubume bomgca kwaye imisela usetyenziso oluphambili Imigca kunye nokutshintsha kwenziwa yiI-ONU.
Indlela yokutshintsha ukhuseleko lwenkqubo ye-PON inokuxhasa ukubuyiswa ngokuzenzekelayo okanye ukubuyiswa ngesandla kweenkonzo ezikhuselweyo. Kwimodi yokubuyisela ngokuzenzekelayo, emva kokuphelisa ukungaphumeleli kokutshintsha, emva kwexesha elithile lokulinda ukubuya, inkonzo ekhuselweyo kufuneka ibuyele ngokuzenzekelayo kwindlela yokuqala yokusebenza. Ixesha lokulinda lokubuya linokusetwa.