Uhlelo lwe-EPON luqukethe amayunithi enethiwekhi amaningi optical (I-ONU), itheminali yomugqa wokubona (OLT), kanye nenethiwekhi eyodwa noma ngaphezulu yokubona (bona Umfanekiso 1). Esiqondisweni sesandiso, isignali ethunyelwe yi-OLTisakazwa kubo bonkeAma-ONU. 8h Lungisa ifomethi yozimele, chaza kabusha ingxenye engaphambili, bese wengeza isikhathi nokuhlonza okunengqondo (LLID)). I-LLID ikhomba ngayinyeI-ONUohlelweni lwe-PON, futhi i-LLID icacisiwe phakathi nenqubo yokutholwa.
(1) Ukuhamba
Kusistimu ye-EPON, ibanga elibonakalayo phakathi kwendawo ngayinyeI-ONUkanye neOLTesiqondisweni sokudlulisa ulwazi phezulu nomfula asilingani. Isistimu ye-EPON evamile icacisa ukuthi ibanga elide phakathi kwaloI-ONUfuthiOLTngu-20km, kanti ibanga elifushane ngu-0km. Lo mehluko webanga uzodala ukubambezeleka kwehluke phakathi kuka-0 no-200 us. Uma lingekho igebe elanele lokuzihlukanisa, izimpawu ezivela ezinhlobonhloboAma-ONUingase ifinyelele ekupheleni kokuthola kweOLTngesikhathi esifanayo, okuzodala ukungqubuzana kwamasignali akhuphuka nomfula. Ukungqubuzana kuzodala inani elikhulu lamaphutha nokulahlekelwa kokuvumelanisa, njll., okubangela isistimu ukuthi ihluleke ukusebenza ngendlela evamile. Usebenzisa indlela yokuhlukanisa, qala ngokukala ibanga elibonakalayo, bese ulungisa zonkeAma-ONUebangeni elifanayo elinengqondo njengeOLT, bese wenza indlela ye-TDMA ukuze uzuze ukugwema ukungqubuzana. Njengamanje, izindlela ezihlukene ezisetshenziswayo zifaka ukuhlukahluka kwe-spectrum, ukuphuma ngaphandle kwebhendi kanye nokuvulwa kwamafasitela okungaphakathi kwebhendi. Isibonelo, indlela yokulinganisa ithegi yesikhathi isetshenziselwa ukulinganisa kuqala isikhathi sokulibaziseka kweluphu yesiginali kusukela ngakunyeI-ONUkweOLT, bese ufaka inani elithile le-Td lokulibaziseka kokulinganisa kokukodwaI-ONU, ukuze isikhathi sokulibaziseka kwe-loop sabo bonkeAma-ONUngemva kokufaka i-Td ( Ebizwa nge-equalization loop delay value Tequ) ziyalingana, umphumela uyafana nalowoI-ONUiyiswa ebangeni elinengqondo njenge-OLT, bese uhlaka lungathunyelwa ngendlela efanele ngokobuchwepheshe be-TDMA ngaphandle kokungqubuzana. .
(2) Inqubo yokuthola
IOLTuthola ukuthiI-ONUohlelweni lwe-PON ithumela imilayezo ye-Gate MPCP ngezikhathi ezithile. Lapho ethola umyalezo weSango, abangabhalisiweI-ONUizolinda isikhathi esingahleliwe (ukugwema ukubhaliswa kanyekanye kokuningiAma-ONU), bese uthumela umlayezo wokubhalisa kuOLT. Ngemva kokubhaliswa ngempumelelo, iOLTyabela i-LLID ku-I-ONU.
(3) I-Ethernet OAM
Ngemva kweI-ONUubhalise neOLT, i-Ethernet OAM ku-I-ONUiqala inqubo yokuthola futhi isungula uxhumano neOLT. I-Ethernet OAM isetshenziswa kuI-ONU/OLTizixhumanisi zokuthola amaphutha esilawuli kude, qalisa ama-loopback akude, futhi uthole ikhwalithi yesixhumanisi. Nokho, i-Ethernet OAM inikeza ukwesekwa kwama-OAM PDU enziwe ngokwezifiso, amayunithi olwazi nemibiko yesikhathi. AbaningiI-ONU/OLTabakhiqizi basebenzisa izandiso ze-OAM ukusetha imisebenzi ekhethekile yeAma-ONU. Uhlelo lokusebenza olujwayelekile ukulawula umkhawulokudonsa wabasebenzisi bokugcina ngemodeli yomkhawulokudonsa yokumisa enwetshwe ku-I-ONU. Lolu hlelo lokusebenza olungajwayelekile luwukhiye wokuhlolwa futhi luba isithiyo ekuxhumaneni phakathiI-ONUfuthiOLT.
(4) Ukugeleza komfula
Lapho i-OLThas traffic ukuthumelaI-ONU, izophatha ulwazi lwe-LLID yendawo okuyiwa kuyoI-ONUemgwaqeni. Ngenxa yezici zokusakaza ze-PON, idatha ethunyelwe yi-OLTizosakazwa kubo bonkeAma-ONU. Kufanele sicabangele ikakhulukazi isimo lapho ithrafikhi engaphansi komfula isakaza ukusakazwa kwesevisi yevidiyo. Ngenxa yemvelo yokusakaza yohlelo lwe-EPON, uma umsebenzisi enza ngendlela oyifisayo uhlelo lwevidiyo, luzosakazwa kubo bonke abasebenzisi, olusebenzisa umkhawulokudonsa ongezansi kakhulu.OLTngokuvamile isekela i-IGMP Snooping. Ingakwazi ukuhlola imilayezo ye-IGMP Joyina Yesicelo futhi ithumele idatha yokusakaza okuningi kubasebenzisi abahlobene naleli qembu esikhundleni sokusakaza kubo bonke abasebenzisi, inciphise ithrafikhi ngale ndlela.
(5) Ukugeleza komfula
Eyodwa kuphelaI-ONUingathumela ithrafikhi ngesikhathi esithile. II-ONUinolayini abaningi ababalulekile (umugqa ngamunye uhambisana nezinga le-QoSI-ONUithumela umbiko wombiko ku-OLTukucela ithuba lokuthumela, ukuchaza isimo somugqa ngamunye. IOLTithumela umyalezo weSango ephendula i-I-ONU, ngitsheleI-ONUisikhathi sokuqala ukudluliswa olandelayo TheOLTkumele ikwazi ukuphatha izidingo zomkhawulokudonsa wonkeAma-ONU, futhi kufanele ibeke phambili imvume yokudlulisela. Ngokusho kuqala kulayini bese ubhalansisa izicelo eziningiAma-ONU, iOLTkumele ikwazi ukuphatha izidingo zomkhawulokudonsa wonkeAma-ONU. Ukwabiwa okunamandla komkhawulokudonsa okhuphukayo womfula (okungukuthi i-algorithm ye-DBA).
2.2 Ngokwezici zobuchwepheshe zohlelo lwe-EPON, izinselele zokuhlola ezibhekene nohlelo lwe-EPON
(1) Kucatshangelwa isikali sohlelo lwe-EPON
Nakuba i-IEEE802.3ah ingachazi inombolo enkulu kusistimu ye-EPON, inombolo enkulu esekelwa uhlelo lwe-EPON isuka ku-16 ukuya ku-128.I-ONUukujoyina uhlelo lwe-EPON kudinga iseshini ye-MPCP kanye neseshini ye-OAM. Njengoba amasayithi amaningi ajoyina i-EPON, ingozi yamaphutha esistimu izokhula. Ngokwesibonelo, ngamunyeI-ONUidinga ukuthola kabusha inqubo, inqubo yokungena futhi iqale iseshini ye-OAM. Ngakho-ke, isikhathi sokutakula salo lonke uhlelo sizokhula ngenani leAma-ONU.
(2) Inkinga yokuxhumana kwemishini
Izici ezilandelayo zicatshangelwa kakhulu ekuxhumaneni kwemishini:
●I-algorithm ye-dynamic bandwidth (DBA) ehlinzekwa abakhiqizi abahlukene ihlukile.
●Abanye abakhiqizi basebenzisa “Izinto Eziqondile Zenhlangano” ye-OAM ukuze bamise ukuziphatha okuthile.
●Ukuthi ukuthuthukiswa kwephrothokholi ye-MPCP kuyahambisana ngokuphelele yini.
● Ukuthi izindlela zokulinganisa ibanga ezithuthukiswe abakhiqizi abahlukene ziyahambisana yini nokucutshungulwa kwewashi.
(3) Izingozi ezifihliwe ekudlulisweni kwezinsizakalo zokudlala kathathu ohlelweni lwe-EPON
Ngenxa yezimpawu zokudlulisela ze-EPON, ezinye izingozi ezifihliwe zizokwethulwa lapho kuthunyelwa izinsizakalo zokudlala kathathu:
● I-downstream imosha umkhawulokudonsa omningi: Uhlelo lwe-EPON lisebenzisa imodi yokusakaza yokusakaza ezansi nomfula: ngayinyeI-ONUuzothola inani elikhulu lethrafikhi elithunyelwa kwabanyeAma-ONU, imosha umkhawulokudonsa omningi oya phansi.
●Ukubambezeleka komfula kukhulu uma kuqhathaniswa: Uma i-I-ONUithumela idatha ku-OLT, kufanele ilinde ithuba lokudlulisela elinikezwe iOLT. Ngakho-ke, i-I-ONUkufanele ivimbele inani elikhulu lethrafikhi ekhuphuka nomfula, okuzobangela ukubambezeleka, i-jitter, nokulahleka kwephakethe.
3 Ubuchwepheshe bokuhlola be-EPON
Ukuhlolwa kwe-EPON ikakhulukazi kufaka phakathi izici ezimbalwa ezifana nokuhlola ukusebenzisana, ukuhlolwa kwephrothokholi, ukuhlolwa kokusebenza kokudluliswa kwesistimu, isevisi nokuqinisekiswa komsebenzi. I-topology yokuhlola evamile iboniswa kuMfanekiso 2. Imikhiqizo ye-IXIA ye-IxN2X inikeza ikhadi lokuhlola le-EPON elizinikele, isixhumi esibonakalayo sokuhlola se-EPON, singathwebula futhi sihlaziye amaphrothokholi e-MPCP ne-OAM, ingathumela ithrafikhi ye-EPON, inikeze uhlelo lokuhlola oluzenzakalelayo, futhi ingasiza abasebenzisi ukuhlola. I-DBA algorithms.
