Inkqubo ye-EPON iqulethe iiyunithi ezininzi ze-optical network (ONU), i-terminal ye-optical line (OLT), kunye nenethiwekhi enye okanye ngaphezulu (jonga umfanekiso 1).Kwisalathiso sokwandisa, isignali ethunyelwe yiOLT isasazwa kuzo zonke ii-ONU.8h Guqula ifomathi yesakhelo, chaza kwakhona inxalenye yangaphambili, kwaye wongeze ixesha kunye nokuchonga okusengqiqweni (LLID)).I-LLID ichonga i-ONU nganye kwindlela ye-PON, kwaye i-LLID icacisiwe ngexesha lenkqubo yokufumanisa.
(1) Ukutshintsha
Kwinkqubo ye-EPON, umgama womzimba phakathi kwe-ONU nganye kunye ne-OLT kwindlela yokuhambisa ulwazi oluphezulu alulingani.Inkqubo ye-EPON ngokubanzi imisela ukuba umgama omde phakathi kwe-ONU ne-OLT yi-20km, kwaye owona mgama umfutshane yi-0km.Lo mahluko womgama uya kubangela ukulibaziseka kwahluka phakathi kwe-0 kunye ne-200 yethu.Ukuba akukho msantsa waneleyo wokuzihlukanisa, iimpawu ezivela kwii-ONU ezahlukeneyo zinokufikelela ekupheleni kokufumana i-OLT ngaxeshanye, okuya kubangela ukungqubana kweempawu zomlambo.Ingxabano iya kubangela inani elikhulu leempazamo kunye nelahleko yokuvumelanisa, njl., kubangela ukuba inkqubo ingaphumeleli ukusebenza ngokuqhelekileyo.Ukusebenzisa indlela yokulinganisa, qala ulinganise umgama womzimba, kwaye ulungelelanise zonke ii-ONU kumgama ofanayo wengqiqo njenge-OLT, kwaye wenze indlela ye-TDMA ukufezekisa ukuphepha ukungqubuzana.Okwangoku, iindlela ezisetyenzisiweyo ezisetyenzisiweyo ziquka ukusasazeka kwe-spectrum, ukuphuma kwe-band kunye ne-band-in-band-opening range.Umzekelo, indlela yokubeka ithegi yexesha isetyenziselwa ukulinganisa kuqala ixesha lokulibaziseka kwe-loop ukusuka kwi-ONU nganye ukuya kwi-OLT, kwaye emva koko ufake i-equalization ethile yokulibaziseka ixabiso le-Td kwi-ONU nganye, ukuze ixesha lokulibaziseka kwe-loop kuzo zonke ii-ONU emva kokufaka i-Td. (Ebizwa ngokuba yi-equalization loop delay value Tequ) ziyalingana, isiphumo siyafana nesokuba i-ONU nganye isiwa kumgama onengqondo ofanayo ne-OLT, kwaye ke isakhelo sinokuthunyelwa ngokuchanekileyo ngokwetekhnoloji yeTDMA ngaphandle kongquzulwano..
(2) Inkqubo yokufumanisa
I-OLT ifumanisa ukuba i-ONU kwinkqubo yePON ithumela imiyalezo yeSango MPCP ngamaxesha athile.Emva kokufumana umyalezo weSango, i-ONU engabhaliswanga iya kulinda ixesha elingalindelekanga (ukuphepha ukubhaliswa kwangaxeshanye kwee-ONU ezininzi), kwaye emva koko uthumele umyalezo oBhalisa kwi-OLT.Emva kobhaliso oluyimpumelelo, iOLT yabela i-LLID kwi-ONU.
(3) I-Ethernet OAM
Emva kokuba i-ONU ibhalise kunye ne-OLT, i-Ethernet OAM kwi-ONU iqala inkqubo yokufumanisa kwaye iseke uxhulumaniso kunye ne-OLT.I-Ethernet OAM isetyenziswa kwiikhonkco ze-ONU/OLT ukufumana iimpazamo ezikude, qalisa i-loopbacks ekude, kwaye ibone umgangatho wekhonkco.Nangona kunjalo, i-Ethernet OAM inikezela ngenkxaso yee-PDU ze-OAM ezenziwe ngokwezifiso, iiyunithi zolwazi kunye neengxelo zexesha.Abavelisi abaninzi be-ONU/OLT basebenzisa izandiso ze-OAM ukuseta imisebenzi ekhethekileyo yee-ONU.Isicelo esiqhelekileyo kukulawula i-bandwidth yabasebenzisi bokugqibela kunye nemodeli yoqwalaselo yoqwalaselo eyandisiweyo kwi-ONU.Esi sicelo esingenamgangatho sisitshixo sovavanyo kwaye sibe ngumqobo kwi-intercommunication phakathi kwe-ONU kunye ne-OLT.
(4) Ukuhamba komlambo
Xa i-OLT inetrafikhi yokuthumela i-ONU, iya kuthwala ulwazi lwe-LLID yendawo ekuyiwa kuyo i-ONU kwi-traffic.Ngenxa yeempawu zokusasaza ze-PON, idatha ethunyelwe yi-OLT iya kusasazwa kuzo zonke ii-ONU.Kufuneka siqwalasele ngokukodwa imeko apho i-traffic traffic esezantsi ihambisa imijelo yenkonzo yevidiyo.Ngenxa yobume bokusasazwa kwenkqubo ye-EPON, xa umsebenzisi elungiselela inkqubo yevidiyo, iya kusasazwa kubo bonke abasebenzisi, edla i-bandwidth esezantsi kakhulu.I-OLT ihlala ixhasa i-IGMP Snooping.Iyakwazi ukukhangela i-IGMP Joyina imiyalezo yesicelo kwaye ithumele idatha ye-multicast kubasebenzisi abanxulumene neli qela endaweni yokusasaza kubo bonke abasebenzisi, ukunciphisa i-traffic ngale ndlela.
(5) Ukuhamba komlambo
Inye kuphela i-ONU enokuthumela itrafikhi ngexesha elithile.I-ONU inemigca emininzi ebalulekileyo (umgca ngamnye uhambelana nenqanaba leQoS. I-ONU ithumela umyalezo weNgxelo kwiOLT ukuze icele ithuba lokuthumela, ichaza imeko yomgca ngamnye. I-OLT ithumela umyalezo weSango ngokuphendula kwi-ONU, ixelela I-ONU ixesha lokuqala losasazo olulandelayo I-OLT kufuneka ikwazi ukulawula iimfuno ze-bandwidth kuzo zonke i-ONU, kwaye kufuneka ibeke phambili imvume yokuhambisa.Ngokokubaluleka komgca kunye nokulinganisa izicelo zee-ONU ezininzi, i-OLT kufuneka ikwazi ukulawula iimfuno zebhanwidth kuzo zonke ii-ONU Ulwabiwo oluguquguqukayo lwebhanwidth enyukayo (okt i-algorithm ye-DBA).
2.2 Ngokweempawu zobugcisa zenkqubo ye-EPON, imingeni yovavanyo ejongene nenkqubo ye-EPON
(1) Ukuqwalasela umlinganiselo wenkqubo ye-EPON
Nangona i-IEEE802.3ah ingachazi inani eliphezulu kwinkqubo ye-EPON, inani eliphezulu elixhaswa yinkqubo ye-EPON lisuka kwi-16 ukuya kwi-128. I-ONU nganye ejoyina inkqubo ye-EPON idinga iseshoni ye-MPCP kunye neseshoni ye-OAM.Njengoko iisayithi ezininzi zijoyina i-EPON, umngcipheko weempazamo zenkqubo uya kwanda.Umzekelo, i-ONU nganye idinga ukuphinda ifumanise inkqubo, inkqubo yokungena kwaye iqalise iseshoni ye-OAM.Ngoko ke, ixesha lokubuyisela inkqubo yonke liya kunyuka kunye nenani le-ONU.
(2) Ingxaki yokunxibelelana kwezixhobo
Le miba ilandelayo iqwalaselwa ikakhulu kunxibelelwano lwezixhobo:
● I-algorithm ye-dynamic bandwidth (DBA) enikezelwa ngabavelisi abahlukeneyo yahlukile.
●Abanye abavelisi basebenzisa i-OAM's “Organization Specific Elements” ukuseta iindlela zokuziphatha ezithile.
●Ukuba ngaba uphuhliso lomthetho weMPCP luyahambelana ngokupheleleyo.
●Ingaba iindlela zokulinganisa umgama eziphuhliswe ngabavelisi abohlukeneyo ziyangqinelana nokusetyenzwa kwewotshi.
(3) Iingozi ezifihliweyo ekuhanjisweni kweenkonzo zokudlala kathathu kwinkqubo ye-EPON
Ngenxa yeempawu zothumelo lwe-EPON, ezinye iingozi ezifihlakeleyo ziya kwaziswa xa kuhanjiswa iinkonzo zokudlala kathathu:
● I-Downstream inkunkuma ininzi ye-bandwidth: Inkqubo ye-EPON isebenzisa imodi yokusasazwa kokusasazwa kwi-downstream: nganye i-ONU iya kufumana inani elikhulu lezithuthi ezithunyelwa kwezinye ii-ONU, zichitha ubuninzi be-downstream bandwidth.
●Ulibaziseko olunyukayo luninzi kakhulu: Xa i-ONU ithumela idatha kwi-OLT, kufuneka ilinde ithuba lothumelo elinikezelwe yi-OLT.Ke ngoko, i-ONU kufuneka ikhusele isixa esikhulu setrafikhi enyukayo, eya kubangela ukulibaziseka, ijitter, kunye nokulahleka kwepakethi.
3 iteknoloji yovavanyo lweEPON
Uvavanyo lwe-EPON ikakhulu lubandakanya imiba emininzi efana novavanyo lokusebenzisana, uvavanyo lweprotocol, uvavanyo lwenkqubo yokuhanjiswa kwenkqubo, inkonzo kunye nokuqinisekiswa komsebenzi.Umgangatho wovavanyo we-topology uboniswe kuMfanekiso 2. Iimveliso ze-IXIA ze-IxN2X zibonelela ngekhadi lovavanyo le-EPON elizinikeleyo, ujongano lovavanyo lwe-EPON, lunokuthi lubambe kwaye luhlalutye iiprothokholi zeMPCP kunye ne-OAM, zinokuthumela i-EPON traffic, ibonelela ngenkqubo yovavanyo oluzenzekelayo, kwaye inokunceda abasebenzisi bavavanye. DBA algorithms.
