Ukwethulwa kwezinhlelo ezahlukahlukene ze-PON
1. Ubuchwepheshe be-APON
Maphakathi nawo-1990, abanye o-opharetha benethiwekhi abakhulu basungula i-Full Service Access Network Alliance (FSAN), inhloso yayo kuwukwenza izinga elihlanganisiwe lemishini ye-PON ukuze abakhiqizi bezisetshenziswa nabaqhubi bakwazi ukungena emakethe yemishini ye-PON futhi baqhudelane ndawonye. Umphumela wokuqala ukucaciswa kwezinga lesistimu ye-PON ye-155Mbit / s ochungechungeni lwezincomo ze-ITU-T G.983. Ngenxa yokuthi i-ATM isetshenziswa njengephrothokholi yomphathi, le sistimu ibizwa ngesistimu ye-APON, futhi ngokuvamile ayiqondwa kahle njengehlinzeka ngamasevisi e-ATM kuphela. Ngakho-ke, iqanjwe kabusha ngokuthi uhlelo lwe-Broadband Passive Optical Network (BPON) ukukhombisa ukuthi lolu hlelo lungahlinzeka ngezinsizakalo ze-Ethernet Broadband ezifana nokufinyelela kwenethiwekhi, ukusatshalaliswa kwevidiyo, kanye nemigqa eqashwe ngesivinini esiphezulu. Nokho, kulesi sizukulwane sezinhlelo ze-FSAN, igama elisetshenziswa kakhulu i-APON. Kamuva, izinga le-APON lathuthukiswa, futhi laqala ukusekela amanani e-downlink 622 Mbit / s, futhi izici ezintsha zengezwa ezindleleni zokuvikela, ukwabiwa komkhawulokudonsa oshukumisayo (DBA), nezinye izici.
I-APON isebenzisa i-ATM njengephrothokholi yomphathi. Ukudluliselwa komfula umfula ugeleza ukusakaza kwe-ATM okuqhubekayo ngenani elincane elingu-155.52Mbit / s noma 622.08Mbit / s. Iseli elikhethekile lokuphathwa nokugcinwa kwesendlalelo somzimba (PLOAM) lifakwa emfudlaneni wedatha.Ukudluliswa komfudlana okuphezulu amaseli e-ATM asesimweni sokuqhuma. Ukuze kuzuzwe ukudluliswa kokuqhuma nokwamukela, i-3-byte overhead ebonakalayo yengezwa ngaphambi kweseli ngalinye lamabhayithi angama-53. Ngesilinganiso esiyisisekelo esingu-155.52 Mbit / s, iphrothokholi yokudlulisela isekelwe kuhlaka lwe-downlink oluqukethe amaseli e-ATM angu-56 (amabhayithi angu-53 ngeseli ngayinye); lapho isilinganiso sebhithi sinyuselwa ku-622.08 Mbit / s, ifreyimu ye-downlink inwetshwa ibe ngu-224 Cell. Ngesilinganiso esiyisisekelo esingu-155.52 Mbit / s, ifomethi yohlaka lwe-uplink ingamaseli angu-53, iseli ngalinye linamabhayithi angu-56 (amabhayithi amaseli e-ATM angu-53 kanye namabhayithi angu-3 ngaphezulu). Ngokungeziwe kumaseli edatha angu-54 kufreyimu ye-downlink, kunamaseli amabili e-PLOAM, elilodwa lisekuqaleni kozimele kanti elinye limaphakathi nohlaka. Iseli ngalinye le-PLOAM liqukethe ukugunyazwa kokudluliswa kwe-uplink kweseli ethile kuhlaka olukhuphuka nomfula (amaseli ozimele angama-53 Aphezulu anezibonelelo ezingu-53 ezifakwe kumephu kumaseli e-PLOAM) kanye nolwazi lwe-OAM & P. I-APON ihlinzeka ngemisebenzi ye-OAM enothe kakhulu futhi ephelele, efaka ukuqapha izinga lephutha elincane, okuthusayo, ukutholwa okuzenzakalelayo, nokusesha okuzenzakalelayo. Njengendlela yokuvikela, ingaphenya futhi ibethele idatha ye-downlink.
Ngokombono wokucubungula idatha, ku-APON, idatha yomsebenzisi kufanele idluliselwe ngaphansi kokuguqulwa kwephrothokholi (i-AAL1/2 ye-TDM ne-AAL5 yokudlulisa iphakethe ledatha). Lokhu kuguqulwa kunzima ukuzivumelanisa nomkhawulokudonsa ophezulu, futhi imishini eyenza lo msebenzi ihlanganisa ezinye izinto ezisizayo ezihlobene, njengememori yeseli, i-Glue Logic, njll., ebuye ingeze okuningi kuzindleko zesistimu.
Manje, kungakhathaliseki ukuthi inethiwekhi yokudlulisela ewumgogodla webanga elide noma ungqimba lokuhlangana lwenethiwekhi yokufinyelela endaweni yedolobha elikhulu, ubuchwepheshe bokuxhumana kwedijithali kancane kancane bushintshile busuka ku-ATM-centric kuya ku-IP-based ukuze buhlinzeke ngevidiyo, umsindo, nokuxhumana kwedatha. Ngakho-ke, isakhiwo senethiwekhi yokufinyelela kuphela esingajwayelana nakho kokubili ukufinyelela kwamanje kanye nobuchwepheshe benethiwekhi besikhathi esizayo obungenza inethiwekhi ye-IP ebona konke ibe ngokoqobo.
I-APON ihoxile kancane kancane emakethe ngenxa yobunkimbinkimbi bayo nokusebenza kahle kokudluliswa kwedatha.
2. EPON
Cishe ngesikhathi esifanayo nesistimu ye-APON, i-IEEE iphinde yasungula iqembu lokuqala locwaningo lwe-Ethernet (EFM) elingamakhilomitha lokuqala ukuze liqalise i-EPON esekelwe ku-Ethernet (Ethernet Passive Optical Network) mayelana namanethiwekhi okufinyelela kwefayibha, okubonisa ithemba elihle lemakethe. Iqembu locwaningo lingeleqembu le-IEEE 802.3 elithuthukise izinga le-Ethernet. Ngokufanayo, ububanzi bocwaningo lwayo nalo bukhawulelwe ekwakhiweni kwezakhiwo, futhi kufanele luhambisane nemisebenzi ekhona ye-802.3 media access control (MAC). Ngo-April 2004, iqembu locwaningo lethule izinga le-IEEE 802.3ah le-EPON, ngezinga elikhuphukayo neliphansi le-1 Gbit / s (lisebenzisa u-8B / 10B ikhodi, kanye nesilinganiso somugqa esingu-1.25 Gbit / s), okuqeda abakhiqizi be-EPON ' ukusetshenziswa kwezivumelwano ezizimele ukuthuthukisa isimo esijwayelekile semishini.
I-EPON iwuhlelo lokufinyelela olubanzi olususelwe kubuchwepheshe be-Ethernet. Isebenzisa i-PON topology ukuze isebenzise ukufinyelela kwe-Ethernet. Ubuchwepheshe obubalulekile besendlalelo sesixhumanisi sedatha ikakhulukazi buhlanganisa: I-Multiple Access Control Protocol (MPCP) yesiteshi esixhumanisa phezulu, inkinga yepulaki neyokudlalaI-ONU, izivumelwano zesinxephezelo ezisukela kanye nokubambezeleka kweOLT, nezinkinga zokuhambisana nephrothokholi.
Isendlalelo esibonakalayo se-IEEE 802.3ah sihlanganisa kokubili i-point-to-point (P2P) exhunyiwe imicu ye-optical nezintambo zethusi, kanye nezimo zenethiwekhi ye-PON ye-point-to-multipoint (P2MP). Ukuze kube lula ukusebenza kwenethiwekhi nokulungisa amaphutha, indlela ye-OAM nayo ifakiwe. Nge-topology yenethiwekhi ye-P2MP, i-EPON isuselwe kumshini obizwa nge-Multipoint Control Protocol (MPCP), okuwumsebenzi ongaphakathi kwesendlalelo esingaphansi se-MAC. I-MPCP isebenzisa imilayezo, imishini yesifunda, nezibali-sikhathi ukulawula ukufinyelela ku-topology yenethiwekhi ye-P2MP. Iyunithi ngayinye yenethiwekhi yokubona (I-ONU) ku-topology yenethiwekhi ye-P2MP inebhizinisi lephrothokholi le-MPCP elixhumana nebhizinisi lephrothokholi ye-MPCPOLT. .
Isisekelo sephrothokholi ye-EPON / MPCP iyisendlalelo esingaphansi sokulingisa sokukhomba-kuya-iphuzu, esenza inethiwekhi ye-P2MP ibukeke njengeqoqo lezixhumanisi ze-P2P kuya ezendlalelo zephrothokholi eziphakeme.
Ukuze kuncishiswe izindleko ze-I-ONU, ubuchwepheshe obuyinhloko besendlalelo esibonakalayo se-EPON bugxile kuOLT, okufaka ukuvumelanisa okusheshayo kwamasignali aqhumayo, ukuvumelanisa kwenethiwekhi, ukulawula amandla amamojula we-optical transceiver, nokwamukela okuguquguqukayo.
I-EPON ihlanganisa izinzuzo ze-PON nemikhiqizo yedatha ye-Ethernet ukuze yakhe izinzuzo eziningi ezihlukile. Uhlelo lwe-EPON lunganikeza ama-bandwidths akhuphukayo naphansi afinyelela ku-1 Gbit/s, angahlangabezana nezidingo zabasebenzisi esikhathini esizayo isikhathi eside. I-EPON isebenzisa ubuchwepheshe bokuphindaphinda ukusekela abasebenzisi abaningi, futhi umsebenzisi ngamunye angajabulela umkhawulokudonsa omkhulu. Uhlelo lwe-EPON alusebenzisi imishini ye-ATM ebizayo kanye nemishini ye-SONET, futhi iyahambisana ne-Ethernet ekhona, yenza kube lula kakhulu ukwakheka kwesistimu, izindleko eziphansi, futhi kulula ukuyithuthukisa. Ngenxa yempilo ende yemishini ye-passive optical, izindleko zokulungisa imigqa yangaphandle ziyancipha kakhulu. Ngesikhathi esifanayo, ukuxhumana kwe-Ethernet okujwayelekile kungathatha ithuba lemishini ye-Ethernet ekhona ebiza kancane futhi yonge izindleko. Isakhiwo se-PON ngokwaso sinquma ukuthi inethiwekhi ingakala kakhulu. Uma nje isisetshenziswa esibulalayo sishintshwa, inethiwekhi ingathuthukiswa ibe yi-10 Gbit/s noma ngaphezulu. I-EPON ayikwazi ukuhlanganisa kuphela ikhebula le-TV ekhona, izinsiza zedatha kanye nezwi, kodwa futhi ikwazi ukusebenzisana nezinsizakalo zesikhathi esizayo ezifana ne-TV yedijithali, i-VoIP, inkomfa ngevidiyo ne-VOD, njll., ukuze kuzuzwe ukufinyelela kwesevisi okuhlanganisiwe.
Ukusetshenziswa okuphelele komphathi we-EPON nobunye ubuchwepheshe bokufinyelela buthuthukisa futhi izixazululo zobuchwepheshe bokufinyelela kwe-broadband.
Ukusebenzisa i-EPON kungenza i-DSL iphule umkhawulo webanga elivamile futhi kwandise ukumbozwa. Lapho i-I-ONUihlanganiswe ne-Digital Subscriber Line Access Multiplexer (DSLAM), ububanzi obufinyelelekayo be-DSL kanye neqembu labo labasebenzisi abangase basebenzise bazokwanda kakhulu.
Ngokufanayo, ngokuhlanganisa i-CMTS (I-Cable Modem Termination System) ye-I-ONU, I-EPON inganikeza umkhawulokudonsa ekuxhumekeni kwekhebula okukhona, futhi ivumele abaqhubi bezintambo ukuthi basebenzise amasevisi asebenzisanayo ngempela kuyilapho behlisa izindleko zokwakha nezokusebenza.
Kuzo zombili izimo, opharetha bangakhuphula isisekelo sabasebenzisi ngokusekelwe kusakhiwo sabo senethiwekhi esikhona kanye nokutshalwa kwezimali. I-EPON ingaphinda inwebe i-point-to-point MSPP (Iplathifomu Yokuhlinzeka Ngezinkonzo Eziningi) kanye ne-IP / Ethernet.
Ngaphezu kwalokho, ubuchwepheshe be-EPON bungasetshenziswa futhi ukuxazulula inkinga yedatha ye-uplink yesiteshi sesisekelo kubuchwepheshe bokufinyelela okungenantambo obuhlanganiswe kunethiwekhi eyinhloko.
3.I-GPON
Ngo-2001, i-FSAN yethula umzamo omusha wokulinganisa amanethiwekhi e-PON asebenza ngaphezu kwe-1 Gbit / s. Ngaphezu kokusekela amanani aphezulu, yonke iphrothokholi ivuliwe ukuze kucatshangwe kabusha futhi kutholwe isixazululo esingcono kakhulu nesisebenza kahle ngokusekela izinsiza eziningi, imisebenzi ye-OAM & P kanye nokuqina. Njengengxenye yomsebenzi we-GPON, i-FSAN yaqala ukuqoqa izidingo zawo wonke amalungu ayo (kuhlanganise nama-opharetha amakhulu emhlabeni jikelele), bese isekelwe kulokhu, ibhala idokhumenti ebizwa ngokuthi i-Gigabit Service Requirements (GSR) futhi yakwenza isincomo esisemthethweni ( G.GON. GSR) kuya ku-ITU-T. Izidingo eziyinhloko ze-GPON ezichazwe kufayela le-GSR zimi kanje.
l Isekela izinsizakalo ezigcwele, ezihlanganisa izwi (TDM, SONET / SDH), Ethernet (10/100 Base-T), i-ATM, imigqa eqashiwe, njll.
l Ibanga elingokomzimba elikhavwe okungenani lingama-20km, kanti ibanga eliphusile lilinganiselwe ku-60km.
l Isekela ama-bit rates ahlukahlukene kusetshenziswa iphrothokholi efanayo, okuhlanganisa i-symmetrical 622 Mbit / s, symmetrical 1.25 Gbit / s, downstream 2.5 Gbit / s kanye nomfula okhuphukayo 1.25 Gbit / s, nezinye izilinganiso zebhithi.
l Imisebenzi ye-OAM & P enamandla enganikeza ukuphathwa kwesevisi kokuphela kuya ekupheleni.
l Ngenxa yezimpawu zokusakaza ze-PON, ukuphepha kwezinsizakalo ze-downlink kufanele kuqinisekiswe ezingeni lephrothokholi.
I-FSAN iphakamise ukuthi ukuklanywa kwezinga le-GPON kufanele kuhlangabezane nemigomo elandelayo.
l Isakhiwo sefreyimu singanwetshwa sisuka ku-622Mbit / s siye ku-2.5Gbit / s, futhi sisekela isilinganiso sebhithi e-asymmetric.
l Qinisekisa ukusetshenziswa komkhawulokudonsa ophezulu nokusebenza kahle okuphezulu kwanoma yiliphi ibhizinisi.
l Faka noma iyiphi isevisi (i-TDM nephakethe) kuhlaka lwe-125ms nge-GFP.
l Ukudluliswa okusebenzayo nokungabizi kwezinsizakalo ze-TDM ezimsulwa.
l Ukwabiwa kwe-Dynamic bandwidth ngayinyeI-ONUngokusebenzisa i-bandwidth pointer.
Njengoba i-GPON iphinde yacubungula isicelo kanye nezidingo ze-PON kusukela phansi kuya phezulu, yabeka isisekelo sesixazululo esisha futhi ayisasekelwe ezingeni langaphambilini le-APON, ngakho abanye abakhiqizi bayibiza ngokuthi i-PON yomdabu (i-PON yemodi yemvelo). Ngakolunye uhlangothi, i-GPON igcina imisebenzi eminingi engahlobene ngokuqondile ne-PON, njengemilayezo ye-OAM, i-DBA, njll. Ngakolunye uhlangothi, i-GPON isekelwe kungqimba olusha lwe-TC (transmission convergence). I-GFP (inqubo yokufaka uzimele evamile) ekhethwe yi-FSAN iyiphrothokholi esekelwe kuhlaka evumelanisa ulwazi lwesevisi oluvela kumakhasimende wezinga eliphezulu lenethiwekhi yezokuthutha ngokusebenzisa indlela evamile. Inethiwekhi yezokuthutha ingaba yinoma yiluphi uhlobo lwenethiwekhi, njenge-SONET / SDH kanye ne-ITU-T G.709 (OTN), njll. Ulwazi lwekhasimende lungasuselwa ephaketheni (njenge-IP / PPP, okungukuthi i-IP / Khomba ku-Point protocal , noma amafreyimu e-Ethernet MAC, njll. ), Kungase futhi kube ukusakazwa kwesilinganiso esincane noma ezinye izinhlobo zolwazi lwebhizinisi. I-GFP imiselwe ngokusemthethweni njenge-ITU-T ejwayelekile G.7041. Ngenxa yokuthi i-GFP inikeza indlela ephumelelayo nelula yokudlulisa izinsiza ezihlukene kunethiwekhi yokudlulisela evumelanisiwe, kuhle ukuyisebenzisa njengesisekelo sesendlalelo se-GPON TC. Ngaphezu kwalokho, uma usebenzisa i-GFP, i-GPON TC iyavumelana futhi isebenzisa amafreyimu ajwayelekile e-SONET / SDH 8kHz (125ms), okwenza i-GPON ikwazi ukusekela ngokuqondile izinsiza ze-TDM. Ezingeni elikhishwe ngokusemthethweni le-G.984.3, isiphakamiso se-FSAN ku-GFP njengoba kwamukelwa ubuchwepheshe bokujwayela ungqimba lwe-TC, futhi kwenziwa ukucubungula okwenziwe lula, okuqanjwe indlela ye-GPON encapsulation (GEM, GPONEncapsulationMethod).
Ukusetshenziswa kwesistimu ye-EPON
I-EPON, njengobuchwepheshe obusha bokufinyelela ku-broadband, iyinkundla yokuhlinzeka ngesevisi ephelele engasekela izinsizakalo zedatha kanye nezinsizakalo zesikhathi sangempela njengezwi nevidiyo.
Idizayini yendlela yokubona ye-EPON ingasebenzisa amaza amaza ama-3. Uma ungacabangi ukusekela izinsizakalo ze-CATV noma ze-DWDM, ama-wavelength amabili ngokuvamile asetshenziswa. Uma usebenzisa amaza amaza ama-3, ubude begagasi obukhuphukayo bungu-1310nm, i-wavelength engezansi ngu-1490nm, bese kwengezwa enye i-wavelength engu-1550nm. Ubude begagasi obunyukile obungu-1550nm busetshenziselwa ukudlulisa ngokuqondile amasiginali wevidiyo ye-analog. Ngenxa yokuthi isignali yamanje yevidiyo ye-analog isabuswa izinsiza zomsakazo nethelevishini, kulinganiselwa ukuthi ngeke ithathelwe indawo ngokuphelele amasevisi wevidiyo yedijithali kuze kube u-2015. Ngakho-ke, uhlelo oluklanywe njengamanje lwe-EPON kufanele lusekele kokubili izinsizakalo zevidiyo zedijithali kanye nezinsizakalo zevidiyo ze-analog. I-1490nm yasekuqaleni isaphethe idatha ye-downlink, ividiyo yedijithali kanye nezinsizakalo zezwi, futhi i-1310nm idlulisa amasiginali wezwi lomsebenzisi we-uplink, ividiyo yedijithali ngokufunwa (VOD), futhi icele ulwazi lokulanda idatha.
Amasignali ezwi anezidingo eziqinile zokulibaziseka kanye ne-jitter, futhi i-Ethernet ayinikezi ukubambezeleka kwephakethe elisuka ekupheleni, izinga lokulahlekelwa kwephakethe, namandla okulawula umkhawulokudonsa. Ngakho-ke, indlela yokuqinisekisa ikhwalithi yesevisi uma i-EPON iphakamisa amasignali ezwi kuyinkinga ephuthumayo okufanele ixazululwe.
1. Ibhizinisi le-TDM
Okwamanje, ikhono le-EPON lezinsiza eziningi ezingabazekayo yikhono layo lokudlulisa amasevisi endabuko e-TDM.
Izinsizakalo ze-TDM ezishiwo lapha zifaka izinhlobo ezimbili zezinsizakalo zezwi (i-POTS, Isevisi Yocingo Edumile Yakudala) kanye nezinsizakalo zesekethe (T1 / El, N'64kbit / s imigqa eqashiwe).
Uma amasistimu e-EPON ephethe amasevisi edatha anikezelwe (2048kbit / s noma 13´64kbit / s amasevisi edatha), i-TDM phezu kwe-Ethernet iyanconywa. Isistimu ye-EPON ingasebenzisa ukushintsha kwesekhethi noma i-VolP lapho iphethe amasevisi ezwi.
Eminyakeni embalwa ezayo, ngenxa yokuthi isidingo semakethe sezinsizakalo zesekethe sisesikhulu kakhulu, isistimu ye-EPON iyadingeka ukuthwala womabili iphakethe-kushintshiweamasevisi kanye nesekhethi-kushintshiweamasevisi. I-EFM iyiphatha kanjani i-TDM ku-EPON nokuthi iqinisekisa kanjani ikhwalithi yezinsizakalo ze-TDM. Awekho amalungiselelo athile kubuchwepheshe, kodwa kufanele ahambisane nefomethi yozimele we-Ethernet. I-Multi-service EPON (MS-EPON) yamukela ubuchwepheshe be-E1 Over Ethernet, obuxazulula ngempumelelo inkinga yokujwayela izinsiza ze-TDM kumafreyimu e-Ethernet, okuvumela i-EPON ukuthi ibone ukudluliswa kwezinsiza eziningi kanye nokufinyelela. Ngesikhathi esifanayo, i-MS-EPON inqoba igebe phakathiOLTfuthiI-ONU. Isenzakalo sokuphikisana komkhawulokudonsa okwabelwana ngawo sinikeza abasebenzisi be-Ethernet isiqinisekiso esiqinisekisiwe somkhawulokudonsa.
Indlela ye-encapsulation ye-Ethernet yenza ubuchwepheshe be-EPON bufaneleke kakhulu ekuphatheni izinsizakalo ze-IP, kodwa futhi ibhekene nenkinga enkulu-kunzima ukuthwala izinsizakalo ze-TDM ezifana nedatha yezwi noma yesifunda. I-EPON iyinethiwekhi yokudlulisa e-asynchronous esekwe ku-Ethernet. Ayinalo iwashi elinemba okuphezulu elivunyelaniswe kunethiwekhi yonkana, futhi kunzima ukuhlangabezana nezidingo zesikhathi nokuvumelanisa zamasevisi e-TDM. Ukuze sixazulule inkinga yokuvumelanisa isikhathi sezinsizakalo ze-TDM kuyilapho siqinisekisa ubunzima bobuchwepheshe obufana ne-QoS yezinsizakalo ze-TDM, akumele nje sithuthukise ukwakheka kohlelo lwe-EPON ngokwalo, kodwa futhi sidinga ukusebenzisa ubuchwepheshe obuthile.
Inkomba yokusebenza yesekethekushintshiweisevisi yezwi ikhombisa ukuthi uma uhlelo lwe-EPON lisebenzisa isekethekushintshiweIndlela yokuphatha izinsizakalo zezwi, kufanele ihlangabezane nezidingo ze-YDN 065-1997 "Isicaciso Esijwayelekile Sobuchwepheshe Sezisetshenziswa Zokushintshana Ngocingo zoMnyango Wezikhala Nezokuxhumana" kanye ne-YD / T 1128-2001 "Izisetshenziswa Zokushintsha Ifoni Ejwayelekile" Izicaciso Zobuchwepheshe (Isengezo 1 ) “izidingo zesekethe emsulwakushintshiweizinga lezwi. Ngakho-ke, i-EPON njengamanje inezinkinga ezilandelayo ngamasevisi e-TDM.
① Isiqinisekiso sesevisi ye-TDM ye-QoS: Nakuba umkhawulokudonsa othathwe isevisi ye-TDM umncane, unezidingo eziphezulu ezinkomba ezifana nokulibaziseka, i-jitter, i-drift, nezinga lephutha elincane. Lokhu akudingi nje kuphela ukucabangela indlela yokunciphisa ukubambezeleka kokudlulisela kanye ne-jitter yesevisi ye-TDM phakathi nokwabiwa komkhawulokudonsa oguqukayo we-uplink, kodwa futhi nokuqinisekisa ukuthi isevisi ye-TDM ilawula ngokuqinile ukubambezeleka kanye ne-jitter kuqhinga lokulawula umkhawulokudonsa we-downlink.
② Isikhathi nokuvumelanisa kwamasevisi e-TDM: Amasevisi e-TDM anezidingo eziqinile ikakhulukazi ngesikhathi nokuvumelanisa. I-EPON empeleni iyinethiwekhi yokudlulisa engavumelaniyo esekwe kubuchwepheshe be-Ethernet. Alikho iwashi lokuxhumana ngocingo elinembayo elivumelaniswe kuyo yonke inethiwekhi. Ukunemba kwewashi okuchazwe yi-Ethernet kungu-± 100′10 futhi ukunemba kwewashi okudingekile ngamasevisi endabuko e-TDM ngu-± 50′10. Ngaphezu kwalokho, ngenkathi ihlinzeka ngewashi lezokuxhumana elivumelaniswe kuyo yonke inethiwekhi, idatha ye-TDM kufanele idluliselwe ngezikhathi ezithile ukuze kuhlangatshezwane nezidingo zayo ze-jitter namaphutha.
③ Ukusinda kwe-EPON: Isevisi ye-TDM futhi idinga ukuthi inethiwekhi yabathwali kufanele ibe nokuphila okuhle. Uma kwenzeka ukwehluleka okukhulu, isevisi ingaba ngokwethembekakushintshiwengesikhathi esifushane kakhulu. Ngenxa yokuthi i-EPON isetshenziswa kakhulu ekufinyeleleni ukwakhiwa kwenethiwekhi, isondele kakhulu kubasebenzisi, futhi izinhlelo zokusebenza ezahlukahlukene nezindawo zokusebenzisa ziyinkimbinkimbi. Ithinteka kalula yizici ezingaziwa njengokwakhiwa kwedolobha, okubangela izingozi ezifana nokuphazamiseka kwezixhumanisi. Ngakho-ke, isistimu ye-EPON idingeka ngokushesha ukuze inikeze isisombululo sokuvikela uhlelo esingabizi kakhulu.
2. Amasevisi e-IP
I-EPON idlulisa amaphakethe edatha ye-IP ngaphandle kokuguqulwa kwephrothokholi futhi inokusebenza kahle okuphezulu, okuyifanele kakhulu izinsiza zedatha.
Ubuchwepheshe be-VolP, njengobuchwepheshe obushisayo ekuthuthukisweni, buzuze isilinganiso esithile sokusetshenziswa eminyakeni yamuva, futhi buyindlela ephumelelayo yokuphatha izinsiza zezwi ngamanethiwekhi e-IP. Kuhlelo lwe-EPON, kuyenzeka futhi ukusebenzisa ukufinyelela kumasevisi ocingo endabuko ngokungeza amathuluzi noma imisebenzi ethile ye-VoIP. Kusetshenziswa ubuchwepheshe be-VoIP, inqobo nje uma ukubambezeleka kanye nezici ze-jitter zesevisi yezwi ye-EPON ziqinisekisiwe, eminye imisebenzi ishiywa kudivayisi yokufinyelela ehlanganisiwe yohlangothi lomsebenzisi (i-IAD, Idivayisi Yokufinyelela Ehlanganisiwe) kanye nedivayisi yesango lokufinyelela elimaphakathi ukuze kucutshungulwe isevisi yezwi. Ukudluliswa. Le ndlela ilula ukuyisebenzisa futhi ingafaka ngokuqondile ubuchwepheshe obukhona, kodwa idinga imishini yokungena ehhovisi elimaphakathi ebizayo, izindleko eziphezulu zokwakha inethiwekhi, futhi inqunyelwe ukushiyeka kobuchwepheshe be-VoIP uqobo. Ngaphezu kwalokho, izinsiza zedatha ze-E1 kanye ne-N'64kbit / s azikwazi ukuhlinzekwa.
Uma isistimu ye-EPON isebenzisa i-VoIP ukuphatha amasevisi ezwi, kufanele ihlangabezane nezinkomba zokusebenza ezilandelayo zamasevisi ezwi le-VoIP.
① Isikhathi sokushintsha esiguqukayo sokubhala ngekhodi ngezwi singaphansi kuka-60ms.
② Kufanele ibe nomthamo wokugcina webhafa ongu-80ms ukuze kuqinisekiswe ukuthi akukho ukunqanyulwa kwenkulumo nama-jitters okwenzekayo.
③ Ukuhlola inhloso yezwi: Uma izimo zenethiwekhi zizinhle, inani elimaphakathi le-PSQM lingaphansi kuka-1.5; lapho izimo zenethiwekhi zingezinhle (isilinganiso sokulahlekelwa kwephakethe = 1%, i-jitter = 20ms, ukubambezeleka = 100ms), inani elijwayelekile le-PSQM ngu-<1.8; Uma izimo zizimbi (isilinganiso sokulahlekelwa kwephakethe = 5%, i-jitter = 60ms, ukubambezeleka = 400ms), isilinganiso se-PSQM singaphansi kuka-2.0.
④ Ukuhlolwa kwenkulumo okunesihloko: Uma izimo zenethiwekhi zizinhle, inani elimaphakathi le-MOS ngu> 4.0; lapho izimo zenethiwekhi zingezinhle (isilinganiso sokulahlekelwa kwephakethe = 1%, i-jitter = 20ms, ukubambezeleka = 100ms), inani elijwayelekile le-MOS lingu-<3.5; inethiwekhi Uma izimo zizimbi (izinga lokulahlekelwa kwephakethe = 5%, i-jitter = 60ms, ukubambezeleka = 400ms), inani elijwayelekile le-MOS <3.0.
⑤ Izinga lombhalo wekhodi: G.711, izinga lombhalo wekhodi = 64kbit / s. Ku-G.729a, izinga lekhodi elidingekayo ngu-<18kbit / s. Ku-G.723.1, izinga lekhodi le-G.723.1 (5.3) lingu-<18kbit / s, futhi izinga lekhodi le-G.723.1 (6.3) lingu-<15kbit / s.
⑥ Inkomba yokubambezeleka (ukubambezeleka kwe-loopback): Ukubambezeleka kwe-VoIP kufaka ukulibaziseka kwekhodekhi, ukubambezeleka kwebhafa yokufaka ekugcineni kokwamukela, kanye nokulibaziseka komugqa kwangaphakathi. Uma umbhalo we-G.729a usetshenziswa, ukubambezeleka kwe-loopback kungu-<150ms. Uma umbhalo we-G.723.1 usetshenziswa, ukubambezeleka kwe-loopback kungu-<200ms.
3.Ibhizinisi le-CATV
Ezinsizakalweni ze-CATV ze-analog, i-EPON ingaphinde iphathwe ngendlela efanayo ne-GPON: engeza ubude begagasi (empeleni lobu ubuchwepheshe be-WDM futhi akuhlangene ne-EPON ne-GPON ngokwayo).
Ubuchwepheshe be-PON buyindlela engcono kakhulu yokufinyelela ukufinyelela kwe-broadband ye-FTTx. I-EPON iwubuchwepheshe obusha benethiwekhi yokufinyelela okubonakalayo obudalwe ngokuhlanganisa ubuchwepheshe be-Ethernet kanye nobuchwepheshe be-PON. Ingasetshenziselwa ukudlulisa izwi, idatha kanye nezinsizakalo zevidiyo futhi iyahambisana. Kwamanye amasevisi amasha ngokuzayo, i-EPON izoba ubuchwepheshe obuvelele bokufinyelela kwe-broadband optical yesevisi ephelele kanye nezinzuzo zayo eziphelele njengomkhawulokudonsa ophezulu, ukusebenza kahle okuphezulu, nokunwetshwa okulula.
Uhlelo lokuvikela lwesistimu ye-PON
Ukuze kuthuthukiswe ukwethembeka kanye nokuphila kwenethiwekhi, indlela yokushintsha ukuvikelwa kwefayibha ingasetshenziswa ohlelweni lwe-PON. Indlela yokushintsha yokuvikela i-fiber optical ingenziwa ngezindlela ezimbili: ① ukushintsha okuzenzakalelayo, okubangelwa ukutholwa kwephutha; ② ukushintsha okuphoqelelwe, okubangelwa imicimbi yabaphathi.
Kunezinhlobo ezintathu eziyinhloko zokuvikela i-fiber: ukuvikelwa kwe-backbone fiber redundancy,OLTUkuvikelwa kwe-PON kokungafuneki kwechweba, nokuvikelwa okugcwele, njengoba kukhonjisiwe kuMfanekiso 1.16.
Ukuvikelwa kwe-backbone fiber redundancy (Umdwebo 1.16 (a)): kusetshenziswa imbobo ye-PON eyodwa ene-optical eyakhelwe ngaphakathi engu-1'2shintshakweOLTImbobo ye-PON; usebenzisa i-2: Ayikho i-optical splitter; iOLTithola isimo somugqa; Azikho izidingo ezikhethekile ze-I-ONU.
OLTImbobo ye-PON yokuvikela ukungadingeki (Umfanekiso 1.16 (b)): Imbobo ye-PON elindile isesimweni esibandayo sokulinda, kusetshenziswa u-2: N ohlukanisayo obonakalayo; iOLTithola isimo somugqa, futhi ukushintsha kwenziwa yi-OLT, ngaphandle kwezidingo ezikhethekile zeI-ONU.
Ukuvikelwa okugcwele (Umfanekiso 1.16 (c)): zombili izimbobo ze-PON eziyinhloko neziyisipele zisesimweni sokusebenza; ezimbili 2: Akukho okuhlukanisiwe okubonakalayo okusetshenzisiwe; i-opticalshintshayakhiwe phambi kweI-ONUI-PON port, kanye ne-I-ONUithola isimo somugqa bese inquma ukusetshenziswa okuyinhloko Imigqa futhi ukushintsha kwenziwa yi-I-ONU.
Indlela yokushintsha ukuvikela yohlelo lwe-PON ingasekela ukubuyisela okuzenzakalelayo noma ukubuyisela mathupha kwezinsizakalo ezivikelwe. Ngemodi yokubuyisela ezenzakalelayo, ngemva kokuqeda ukwehluleka kokushintsha, ngemva kwesikhathi esithile sokulinda sokubuyisela, isevisi evikelwe kufanele ibuyele ngokuzenzakalelayo emzileni wokuqala wokusebenza. Isikhathi sokulinda sokubuyisela singasethwa.