1. EPON network qhia
EPON(Ethernet Passive Optical Network) yog ib qho tshiab optical fiber nkag network technology, uas tau txais cov qauv taw tes-rau-multipoint, passive optical fiber kis tau tus mob, raws li high-speed Ethernet platform thiab TDM lub sij hawm faib MAC (MediaAccessControl) media access control mode, Muab ntau yam broadband access technologies rau kev sib koom ua ke. Lub npe hu ua "passive" txhais tau hais tias ODN tsis muaj cov khoom siv hluav taws xob thiab cov khoom siv hluav taws xob, thiab txhua yam muaj cov khoom siv passive xws li optical splitters (Splitter). Nws siv PON thev naus laus zis ntawm lub cev txheej, Ethernet raws tu qauv ntawm txheej txuas, thiab siv PON topology kom ua tiav Ethernet nkag. Yog li ntawd, nws muab cov txiaj ntsig zoo ntawm PON thev naus laus zis thiab Ethernet thev naus laus zis: tus nqi qis, siab bandwidth, muaj zog scalability, hloov tau yooj yim thiab ceev cov kev pab cuam reorganization, compatibility nrog Ethernet uas twb muaj lawm, yooj yim tswj, thiab hais txog.
EPON tuaj yeem paub txog kev sib koom ua ke ntawm lub suab, cov ntaub ntawv, video, thiab cov kev pabcuam txawb. EPON system feem ntau yog tsim los ntawmOLT(optical kab davhlau ya nyob twg),ONU(optical network unit), ONT (optical network davhlau ya nyob twg) thiab ODN (optical distribution network). Nws yog nyob rau theem nkag ntawm lub network ntawm lub network thiab feem ntau haum rau kev sib txuas ntawm fiber ntau ntawm cov kev pabcuam broadband. Hauv.
Cov khoom siv hauv network muaj xws li cov khoom siv hauv chaw ua haujlwm hauv nruab nrab (OLT) thiab optical network unit (ONU). Optical network unit (ONU) muab cov neeg siv nrog kev sib txuas ntawm cov ntaub ntawv, video, thiab xov tooj sib txuas thiab PON. Thawj lub luag haujlwm ntawmONUyog kom tau txais cov teeb liab kho qhov muag thiab tom qab ntawd hloov nws mus rau hauv hom ntawv uas tus neeg siv xav tau (Ethernet, IP tshaj tawm, xov tooj, T1 / E1, thiab lwm yam).OLTcov cuab yeej txuas nrog IP core network los ntawm optical fiber. Cov kev taw qhia ntawm lub optical access network muaj kev pab them nqi mus txog 20km, uas xyuas kom meej tias covOLTtuaj yeem hloov kho mus rau cov tsoos metropolitan convergence node los ntawm thawj theem ntawm optical access network tsim, yog li simplifying lub network qauv ntawm convergence txheej ntawm kev nkag tau network thiab txuag tus naj npawb ntawm cov chaw ua haujlwm kawg. Tsis tas li ntawd, cov yam ntxwv ntawm kev siv kho qhov muag network lub peev xwm loj, kev siv bandwidth siab, kev ntseeg siab, thiab ntau qhov kev pabcuam QoS qib kev txhawb nqa muaj peev xwm kuj tau ua rau kev hloov pauv ntawm kev nkag mus rau hauv lub network mus rau kev sib koom ua ke, kev sib koom ua ke, thiab muaj txiaj ntsig tus neeg tuav lub platform muaj tseeb.
2. Cov Ntsiab Cai ntawm EPON Network
EPON system siv WDM thev naus laus zis kom paub txog ib leeg-fiber bidirectional kis tau tus mob, siv upstream 1310nm thiab downstream 1490nm wavelengths xa cov ntaub ntawv thiab lub suab, thiab CATV cov kev pabcuam siv 1550nm wavelength los nqa. CovOLTyog muab tso rau hauv lub hauv paus chaw ua hauj lwm los faib thiab tswj kev sib txuas ntawm cov channel, thiab muaj kev saib xyuas, kev tswj xyuas thiab kev ua haujlwm ntawm lub sijhawm. CovONUyog muab tso rau ntawm tus neeg siv sab, thiab covOLTthiab covONUtau txuas nrog 1: 16 / 1: 32 los ntawm kev faib khoom siv kho qhov muag. Txhawm rau cais cov teeb liab los ntawm ntau tus neeg siv ntawm tib lub fiber ntau, ob txoj kev siv multiplexing hauv qab no tuaj yeem siv.
(1) Cov ntaub ntawv downstream kwj siv siv tshuab tshaj tawm. Nyob rau hauv EPON, cov txheej txheem ntawm downstream cov ntaub ntawv kis tau tus mob los ntawm lubOLTmus rau ntau yamONUsyog xa los ntawm cov ntaub ntawv tshaj tawm. Cov ntaub ntawv yog tshaj tawm downstream los ntawm lubOLTmus rau ntau yamONUsnyob rau hauv daim ntawv ntawm kev sib txawv-ntev cov ntaub ntawv packets. Txhua pob ntawv cov ntaub ntawv muaj EPON pob ntawv header, uas tshwj xeeb txheeb xyuas seb cov ntaub ntawv pob ntawv raug xa mus rauONU-1,ONU-2 lubONU-3. Nws tseem tuaj yeem raug cim raws li cov ntaub ntawv tshaj tawm xov xwm xa mus rau txhua tusONUslos yog rau ib qho tshwj xeebONUpab pawg (pob ntawv cov ntaub ntawv multicast). Thaum cov ntaub ntawv tuaj txog ntawm lubONU, covONUtau txais thiab lees paub cov ntaub ntawv pob ntawv xa mus rau nws los ntawm qhov chaw nyob sib txuam, thiab muab pov tseg cov ntaub ntawv pob ntawv xa mus rau lwm tusONUs. Ib qho tshwj xeeb LLID raug faib tom qabONUtau sau npe; tusOLTpiv cov npe LLID thaum tau txais cov ntaub ntawv, thiab thaum twgONUtau txais cov ntaub ntawv, nws tsuas yog tau txais thav duab lossis tshaj tawm cov thav ntawv uas phim nws tus kheej LLID.
(2) Upstream cov ntaub ntawv ntws siv TDMA thev naus laus zis. CovOLTpiv cov npe LLID ua ntej tau txais cov ntaub ntawv; txhuaONUxa cov ntaub ntawv ncej nyob rau hauv lub sij hawm slot uniformly faib los ntawm lub hauv paus chaw ua hauj lwm cov khoomOLT; lub sijhawm teem sijhawm (los ntawm kev siv thev naus laus zis) them nyiaj rau qhov sib txawv ntawm qhov deb ntawm txhua tusONUthiab zam txhuaONUKev sib tsoo ntawm.
