Chekutanga, dambudziko ripi rinoshandiswa nePON kugadzirisa?
● Nekubuda kwemasevhisi epamusoro-soro akadai sevhidhiyo pazvinenge zvichidiwa, mitambo yepamhepo neIPTV, vashandisi vari kuda kukurumidza kuwedzera bandwidth.Nzira dziripo dzeADSL-based Broadband access dziri kuramba dzichinetsa kusangana nezvinodiwa nemushandisi wepamusoro bandwidth, mbiri- nzira yekufambisa kugona, uye chengetedzo.
● Pamusana pekufamba kwenguva refu, simba rinopesana nekupindira uye simba guru, optical fiber yakashandiswa zvakanyanya mumusana wemusana. Mumakore achangopfuura, nekudzikira kwemutengo weiyo optical mudziyo, iyo optical fiber zvishoma nezvishoma yave sarudzo yekutanga kune yekufambisa svikiro yetiweki yekuwana.
● Passive Optical Network (PON) inodhura zvishoma mufiber access mode uye inogona kuvandudzwa zvakanaka. Iri kuwedzera kufarirwa nevashandisi venhare uye inoonekwa semhinduro yakanaka yekugadzirisa dambudziko re "maira yekupedzisira".
Chechipiri, kuumbwa kwePON
Iyo PON ine zvikamu zvitatu: an optical line kuguma (OLT), an optical network unit (ONU), uye passive optical splitter (POS).
PON is asymmetric, point-to-multipoint (P2MP) chimiro. Mabasa anoitwa nevaOLTuyeONUzvakasiyana. TheOLTyakaenzana nebasa raTenzi, uyeONUzvakaenzana nebasa reMuranda.
Chechitatu, zvakanakira PON:
● Kuchengeta
P2P - No optical fibers; 2N optical transceiver
P2PCurb - 1 fiber; 2N+2 optical transceiver; inoda magetsi emunharaunda; inochengetedza yakawanda fiber
P2MP (PON) - 1 fiber; N+1 optical transceiver; nhamba huru ye optical fibers yakachengetwa; nhamba huru ye optical transceivers
● Akavimbika
Chiratidzo hachipfuure nepakati pechigadzirwa chemagetsi chinoshanda panguva yePON yekufambisa nzira, inoderedza zvakanyanya mukana wekutadza;
Iko kushandiswa kwezvishandiso zvepasirese kunorerutsa iyo network hierarchy, uye iyo flattened network chimiro chiri nyore kuchengetedza uye kubata.
● Nhambo refu
Iyo PON yekufambisa kureba ndeye gumi kusvika 20km, iyo inokunda zvachose kudzikiswa kwechinhambwe pakati peEthernet uye xDSL nzira dzekuwana, uye inosimudzira zvakanyanya kuchinjika kweiyo opareta yekupedzisira hofisi kutumira.
● High bandwidth
Kuenzaniswa nexDSL, PON ine yakakwirira bandwidth uye inonyatsozadzisa zvinodiwa zveramangwana HDTV nhepfenyuro yepamhepo masevhisi.
● Anochinja-chinja
Iyo PON networking modhi haina kuganhurirwa, uye network yemuti uye nyeredzi topology inogona kuvakwa zviri nyore.
Iyo PON inonyanya kukodzera nguva dzekuti mushandisi awane ruzivo mapoinzi akapararira, uye trunk optical fiber inogona kugutsa kuwanikwa kwevashandisi vese kuwana ruzivo.
Chechina, chiyero chikuru chePON
● GPON - GigabitPON, ITUG.984 protocol standard, kusimudzira uye kuwedzera kweAPON, uchishandisa chimiro chechimiro chechimiro chekupa rubatsiro rwemhando dzakasiyana-siyana. Nhamba yepamusoro ndeye 2.5Gbps. GPON ine zvakanakira mukumhanya kukuru uye kutsigirwa kwesevhisi akawanda, asi tekinoroji yakaoma, mutengo wakakwira, uye kukura kwechigadzirwa hakuna kukwirira.
● EPON——Ethernetover PON, IEEE802.3ah protocol standard, iyo inotumira Ethernet fomati packet paPON network uye inogona kutsigira 1.25Gbps symmetric rate. EPON yakavakirwa paEthernet tekinoroji uye protocol iri nyore uye inoshanda. Kuenzaniswa neAPON, GPON ine mabhenefiti ari pachena maererano nemutengo.
Chechishanu,Makiyi matekinoroji eEPON
● Channel multiplexing
Iyo EPON sisitimu inotora WDM tekinoroji yekuziva imwe-fiber bidirectional transmission;
Chiyero chechiteshi ndeye 1.25 Gbps kumusoro nekudzika.
● EPON downlink transmission mode - kutepfenyura maitiro
● EPON uplink transmission mode - TDMA mode
● Multipoint Control Protocol - MPCP
Kusiyana neiyo Ethernet P2P architecture, PON iP2MP yekuvaka. TheONUinokwikwidza uplink chiteshi zviwanikwa, uye nzira yekupokana inodiwa kudzivirira uplink data kudhumhana uye kugovanisa zviwanikwa zvechiteshi. Iyo 802.3ah protocol inotsanangura inoenderana inodzora protocol, iyo Multi-point MAC Control Protocol (MPCP);
lMPCP inonyanya kutsanangura Multi-point MAC Control sublayer kuwedzera uye kutsiva iyo MAC Control sublayer inotsanangurwa ne802.3 protocol. Iyo yekudzora furemu yeMPCP protocol ine yepamusoro yepamusoro kupfuura iyo MACClient data furemu.
● Kuverengera uye kunonoka muripo
Iyo EPON uplink transmission inotora iyo TDMA modhi. TheOLTinosarudza nguva yeONUkutumira data. Kubva imwe neimweONUzvakasiyana neOLT, pachava nekunonoka kusiyana. Kana pasina kunonoka muripo wekugadzirisa maitiro, iyo uplink data yekufambisa gakava ichiri kuitika.
EPON kutangira uye kunonoka muripo ndiwo akakosha matekinoroji euplink chiteshi kuwanda. Ø MuDiscoveryProcessing process, iyoOLTinoverengera kukosha kweRTT (RoundTrip Time) yega yegaONUnekuyera vachangobva kunyoreswaONU.
TheOLTinoshandisa RTT kugadzirisa nguva yekubvumidza yega yegaONU.
TheOLTinogona zvakare kutanga kubva painogashira MPCP PDU.
RTT kuverenga:
Iyo GATE furemu ine "timestamp" ndima iyo iyoONUinoshandisa kuzorodza rejista yenguva yemuno. TheOLTinogona kuverenga iyo RTT kuburikidza neyakagamuchirwa REPORT furemu kuita muripo wekuyedza.
● Dynamic Bandwidth Allocation (DBA)
Kuenzanisa kweyakagadziriswa nguva inotsvedza uye inosimba nguva inotsvedza:
