FTTH Access Network Raws li GPON
Kev cog qoob loo rau kev kub ceev hauv internet qhib cov kev siv yees tshiab uas muaj peev xwm muaj kev sib tw muaj tseeb. Qhov no ua rau cov neeg lag luam hauv kev lag luam yuav tsum xav txog qhov siab ntim-tawm ntawm cov khoom siv fiber ntau qhov muag. Thiaj li yuav cia cov kev sib txuas ceev, qhov muag kho fiber ntau tau los ze zog thiab ze rau tus neeg siv. Tom qab ntawd FTTH (Fiber Hom Rau Tsev) zoo nkaus li xaiv lub hom phiaj ntev tshaj plaws vim tias nws yuav yooj yim rau kev nce cov bandwidth rau yav tom ntej yog tias cov neeg tau txais kev pab cuam los ntawm qhov muag fibers. FTTH yog ib txoj hauv kev tiv thaiv yav tom ntej los muab kev pabcuam broadband.
Kev siv lub tshuab ua kom zoo tshaj plaws (PON) raws li FTTH access network yog ib qho point-to-multipoint, fiber ntau rau cov vaj tse network architecture uas siv cov cuab yeej nruab nrag tsis siv los ua kom muaj fiber ntau optical fiber ntau qhov chaw, feem ntau 32-128. Lub GPON FTTH access network yog qhov tseem ceeb hauv cov lus no.
Kev ua zoo ntawm WDM (wavelength division multiplexing), PON siv ib lub piam sij rau cov tsheb khiav qis thiab lwm rau cov tsheb khiav qis rau ib tus qauv. Lub OLT (Optical Line Terminal) yog lub ntsiab ntawm lub network. Muab tso rau hauv qhov chaw txauv hauv zos, OLT yog lub cav uas tsav FTTH system. OLT ua haujlwm ntawm kev khiav tsheb npav, kev tswj tsis tau thiab kev faib nyiaj txiag. Optical splitter splits zog ntawm lub teeb liab thiab ua rau kev sib koom ntawm txhua lub fiber ntau los ntawm ntau cov neeg siv. ONT (Optical Network Terminal) tau muab tso rau hauv tus neeg mob lub tsev thiab txuas nrog OLT los ntawm qhov muag fiber ntau thiab tsis muaj cov ntsiab lus muaj nyob hauv qhov txuas.
Nrog ib tsob ntoo topology, GPON muaj peev xwm tsim kom muaj kev pab nrog qhov tsawg kawg nkaus network splits, yog li txo qhov kho qhov muag fais fab. Ib qhov FTTH access network muaj tsib qhov kev siv, xws li thaj tsam network, ib cheeb tsam chaw ua haujlwm, ib thaj chaw, chaw faib khoom thiab ib thaj chaw raws li hauv daim duab nram qab no.
Lub hauv paus tseem ceeb muaj xws li ISP (Internet service provider) cov khoom siv, PSTN (pob ntawv hloov chaw lossis lub voj voog ntawm legacy switched) thiab cov khoom siv cable TV. Lub luag haujlwm tseem ceeb ntawm lub hauv paus chaw ua hauj lwm yog los tuav lub OLT thiab ODF thiab muab kev tsim nyog siv zog. Qhov chaw pub rau noj yog ncua ntawm ODF (optical tech frames) nyob hauv CO (central office) rau qhov chaw faib khoom. Distribution cable txuas theem-1 splitter nrog theem-2 splitter. Qib-2 splitter feem ntau yog nyob hauv ib lub rooj xaib uas muab tso rau ntawm qhov chaw nkag ntawm lub zej zog. Hauv thaj chaw neeg siv, cov cab cab lag luam raug siv coj los txuas rau theem-2 splitter rau cov neeg siv chaw.
Cov ntaub ntawv yog xa los ntawm OLT mus ONT nyob rau hauv hauv qab raws li kev tshaj tawm thiab raws li lub sij hawm faib multiplexing (TDM) hauv ntws sab nraud. Lub wavelength ntawm cov ntaub ntawv nram qab no yog 1490 nm. Core network cov kev pab cuam thauj mus rau hauv lub tshuab kho qhov muag nce mus txog ntawm OLT thiab ces muab faib rau ONT los ntawm FTTH network los ntawm dint ntawm fais fab tuag. Txhua lub tsev tau txais cov ntawv npaj rau nws los ntawm nws tus kheej. Lub ntws nruab nrab yog nruab nrab ntawm cov ntaub ntawv kis tau los ntawm ONT rau OLT thiab lub wavelength yog 1310 nm. Yog hais tias cov teeb meem ntawm ONTs sib txawv los txog ntawm cov tswv yim splitter tib lub sij hawm thiab nyob rau ntawm lub wavelength 1310 nm, nws yuav ua rau kev hloov ntawm ntau tshaj ONT pib thaum nws tuaj txog OLT. Yog li TDMA tau txais kev swv kom tsis txhob cuam tshuam cov teeb meem ntawm ONTs. Nyob rau hauv TDMA lub sijhawm qhib yuav muab rau txhua tus neeg siv ntawm kev thov rau lawv cov ntawv tuaj. Ntawm cov khoom muag kho qhov muag tau pom zoo tuaj thiab lawv tau ua ke thiab xa mus rau OLT.
Tsab ntawv no nthuav txog cov khoom, architecture, thiab khiav tsheb hauv GPON FTTH access network. Cov ntsiab lus yuav tsis tau ntxaws, tab sis GPON FTTH network architecture yog tseeb ntseeg, scalable, thiab ruaj ntseg. Nws yog ib qho kev sib koom ua ke, yog li tsis muaj ib qho ntawm cov pa roj carbon monoxide mus rau tus neeg siv qhov kawg, uas ua rau cov neeg siv nyiaj tsawg thiab txo cov nqi. Nws yog ib qho kev tsim ua qauv rau lub neej yav tom ntej.
