Nke mbụ, kedu nsogbu a na-eji PON dozie?
● Site na mmalite nke ọrụ bandwit dị elu dị ka vidiyo na-achọ, egwuregwu ịntanetị na IPTV, ndị ọrụ na-achọ ngwa ngwa nke ịba ụba bandwidth. ikike nnyefe ụzọ, na nchekwa.
● N'ihi ogologo nnyefe dị ogologo, ikike mgbochi mgbochi siri ike na nnukwu ikike, a na-eji eriri anya eme ihe na netwọk azụ azụ.N'ime afọ ndị na-adịbeghị anya, na mbelata nke ọnụahịa nke ngwa ngwa anya, eriri anya ejiri nwayọọ nwayọọ ghọọ nhọrọ mbụ maka nnyefe nnyefe nke netwọk ohere.
● Passive Optical Network (PON) dị ọnụ ala n'ụdị ịnweta eriri ma nwee ike ịkwalite nke ọma.Ndị na-ahụ maka telecom na-enwewanye mmasị na ya, a na-ewerekwa ya dị ka ihe ngwọta dị mma iji dozie nsogbu "mile ikpeazụ".
Nke abụọ, ihe mejupụtara PON
PON nwere akụkụ atọ: njedebe eriri anya (OLT), otu netwọk anya anya (ONU), na pasive optical splitter (POS).
PON bụ ihe asymmetric, point-to-multipoint (P2MP).Ọrụ ndị OLT na ndị ONU na-arụ dị iche.OLT dabara na ọrụ Nna-ukwu, na ONU dabara na ọrụ nke Ohu.
Nke atọ, uru PON:
● Na-echekwa
P2P - N eriri anya;2N transceiver ngwa anya
P2PCurb - 1 eriri;2N + 2 transceiver anya;chọrọ ọkụ ọkụ mpaghara;na-azọpụta ọtụtụ eriri
P2MP (PON) - 1 eriri;N + 1 transceiver anya;nnukwu ọnụ ọgụgụ nke eriri anya echekwara;ọnụ ọgụgụ buru ibu nke transceivers anya
● A pụrụ ịdabere na ya
Mgbama ahụ anaghị agafe ngwaọrụ eletrọnịkị na-arụ ọrụ n'oge usoro nnyefe PON, na-ebelata oke ihe nwere ike ịdaba;
Iji ngwaọrụ ndị na-agafe agafe na-eme ka ndị isi netwọk dị mfe, na nhazi netwọk gbawara agbawa dị mfe ijikwa ma jikwaa.
● Ebe dị anya
Ogologo nnyefe PON bụ 10 ruo 20km, nke na-emeri kpam kpam njedebe nke anya dị n'etiti Ethernet na ụzọ ịnweta xDSL, ma na-eme ka mgbanwe dị ukwuu nke ntinye ọrụ njedebe nke onye ọrụ.
● Nnukwu bandwit
E jiri ya tụnyere xDSL, PON nwere bandwidth dị elu ma na-egbo mkpa nke ọrụ mgbasa ozi n'ịntanetị HDTV n'ọdịnihu.
● Na-agbanwe agbanwe
Ụdị ịkparịta ụka n'Ịntanet PON ejedebeghị, yana netwọk osisi na topology nwere ike wuo ya nke ọma.
PON dabara adaba maka oge ebe ndị ọrụ nweta ihe ọmụma gbasasịa, na eriri anya akpati nwere ike imeju ohere nke ndị ọrụ niile ịnweta ebe ozi.
Nke anọ, isi ọkọlọtọ PON
● GPON - GigabitPON, ụkpụrụ protocol ITUG.984, nkwalite na ndọtị nke APON, na-eji usoro etiti na-emekarị iji nye nkwado maka ọrụ dị iche iche.Oke kacha bụ 2.5Gbps.GPON nwere uru na nnukwu ọsọ na nkwado maka ọtụtụ ọrụ, ma nkà na ụzụ dị mgbagwoju anya, ọnụ ahịa dị elu, na ntozu nke ngwaahịa adịghị elu.
● EPON——Ethernetover PON, IEEE802.3ah ọkọlọtọ ọkọlọtọ, nke na-ebufe ngwugwu usoro Ethernet na netwọk PON ma nwee ike ịkwado ọnụego symmetrical 1.25Gbps.EPON dabere na teknụzụ Ethernet yana usoro ahụ dị mfe ma rụọ ọrụ nke ọma.Tụnyere APON, GPON nwere uru doro anya n'ihe gbasara ọnụ ahịa.
Nke ise, isi teknụzụ nke EPON
● Ọwa multiplexing
Sistemụ EPON na-anabata teknụzụ WDM iji ghọta nnyefe bidirectional otu-fiber;
Ọnụego ọwa bụ 1.25 Gbps elu na mgbada.
● Ọnọdụ nnyefe ala EPON - ọnọdụ mgbasa ozi
● EPON uplink nnyefe mode – TDMA mode
● Multipoint Control Protocol – MPCP
N'adịghị ka ụlọ ọrụ Ethernet P2P, PON bụ ihe owuwu P2MP.Ndị ONU na-asọ mpi maka akụrụngwa ọwa uplink, yana usoro mkpezi dị mkpa iji zere ndakọrịta data njikọ na iji kesaa akụrụngwa ọwa nke ọma.Usoro 802.3ah na-akọwapụta ụkpụrụ njikwa kwekọrọ, Multi-point MAC Control Protocol (MPCP);
lMPCP na-akọwakarị sublayer MAC Control Multi-point iji gbatịa ma dochie sublayer njikwa MAC nke akọwapụtara 802.3 protocol.Igwe njikwa nke usoro MPCP nwere mkpa dị elu karịa etiti data MAClient.
● Ịkwụ ụgwọ na-egbu oge
The EPON uplink nnyefe nakweere TDMA mode.OLT na-ekpebi oge maka ONU izipu data.Ebe ONU nke ọ bụla dị iche na OLT, a ga-enwe ọdịiche igbu oge.Ọ bụrụ na enweghị usoro nkwụghachi ụgwọ igbu oge dị irè, esemokwu nnyefe data uplink ka ga-eme.
Nkwụghachi ụgwọ EPON na igbu oge bụ teknụzụ bụ isi maka ịgbasa ọwa uplink multiplex.Ø Na usoro DiscoveryProcessing, OLT na-agbakọ uru RTT (RoundTrip Time) nke ONU nke ọ bụla site n'ịtụ ONU edebanyere aha ọhụrụ.
OLT na-eji RTT hazie oge ikike nke ONU ọ bụla.
OLT nwekwara ike ibido dị iche iche mgbe ọ natara MPCP PDU.
Mgbakọ RTT:
Oghere GATE nwere mpaghara “timestamp” nke ONU na-eji mee ka ndebanye oge mpaghara dị ọhụrụ.OLT nwere ike gbakọọ RTT site na etiti REPORT enwetara iji kwụọ ụgwọ nnwale.
● Oke bandwit dị ike (DBA)
Ntụle nke oghere oge a kapịrị ọnụ na oghere oge dị ike:
