Kodi PON ndi chiyani? Ukadaulo wofikira pa Broadband ukuchulukirachulukira, ndipo ukuyenera kukhala bwalo lankhondo komwe utsi sudzatha. Pakali pano, zoweta zoweta akadali ADSL luso, koma ochulukirachulukira opanga zida ndi opareshoni atembenukira ku luso kuwala maukonde kupeza.
Mitengo yamkuwa ikupitilirabe kukwera, mitengo yazingwe ikupitilirabe kutsika, ndipo kufunikira kwa IPTV ndi masewera a kanema akuyendetsa kukula kwa FTTH. Chiyembekezo chokongola chosintha chingwe chamkuwa ndi chingwe cha coaxial cha mawaya pogwiritsa ntchito chingwe cha kuwala, telefoni, chingwe TV, ndi sewero la data la burodibandi katatu zimawonekera.
Chithunzi 1: PON topology
PON (Passive Optical Network) passive Optical network ndiye ukadaulo waukulu kuzindikira FTTH CHIKWANGWANI kunyumba, kupereka mfundo-to-multipoint CHIKWANGWANI mwayi, monga momwe chithunzi 1, ndiOLT(optical line terminal) ndi mbali ya ogwiritsa ntchito mbali ya ofesi. TheONU(Optical Network Unit) ndi ODN (Optical Distribution Network) amapangidwa.Nthawi zambiri, downlink imagwiritsa ntchito njira yowulutsa ya TDM ndipo uplink imagwiritsa ntchito njira ya TDMA (Time Division Multiple Access) kuti ipange mfundo-to-multipoint tree topology. Chochititsa chidwi kwambiri pa PON monga ukadaulo wofikira ndi "passive". ODN ilibe zida zamagetsi zamagetsi ndi zida zamagetsi zamagetsi. Zonsezi zimapangidwa ndi zinthu zopanda pake monga zogawanitsa, zomwe zimakhala ndi kasamalidwe kakang'ono komanso ndalama zogwirira ntchito.
Mbiri Yachitukuko ya PON
Kafukufuku waukadaulo wa PON adayamba mu 1995. Mu Okutobala 1998, ITU idatengera mulingo waukadaulo wa PON wozikidwa pa ATM, G, wolimbikitsidwa ndi bungwe la FSAN (netiweki yofikira ntchito zonse). 983. Amatchedwanso BPON (BroadbandPON). Mlingo wake ndi 155Mbps ndipo ukhoza kuthandizira 622Mbps.
EFMA (Ethernetin the First Mile Alliance) inayambitsa lingaliro la Efaneti-PON (EPON) kumapeto kwa 2000 ndi mlingo wa kufala kwa 1 Gbps ndi wosanjikiza ulalo zochokera Efaneti encapsulation yosavuta.
GPON (Gigabit-CapablePON) inaperekedwa ndi bungwe la FSAN mu September 2002, ndipo ITU inalandira G mu March 2003. 984. 1 ndi G. 984. 2 mgwirizano. G. 984.1 Makhalidwe onse a dongosolo lofikira la GPON afotokozedwa.G. 984. 2 imatchula gawo laling'ono lokhudzana ndi kugawa kwa ODN (Optical Distribution Network) la GPON.Mu June 2004, ITU inadutsa G kachiwiri. 984. 3, yomwe imatchula zofunikira za Transmission Convergence (TC) wosanjikiza.
Kuyerekeza kwa EPON ndi zinthu za GPON
EPON ndi GPON ndi mamembala awiri akuluakulu a optical network access, aliyense ali ndi ubwino wake, kupikisana wina ndi mzake, kuthandizira wina ndi mzake ndi kuphunzira kuchokera kwa wina ndi mzake. Izi zikufanizira iwo muzinthu zosiyanasiyana:
Mtengo
EPON imapereka ulalo wosasunthika ndi kutsika kwa 1.25Gbps, pogwiritsa ntchito 8b/10b mzere wa coding, ndipo mtengo wake ndi 1Gbps.
GPON imathandizira magiredi angapo othamanga ndipo imatha kuthandizira kuthamanga kwa uplink ndi downlink asymmetric, 2.5Gbps kapena 1.25Gbps kumunsi kwamtsinje, ndi 1.25Gbps kapena 622Mbps uplink. Malingana ndi zofunikira zenizeni, mitengo ya uplink ndi downlink imatsimikiziridwa, ndipo ma modules optical ofanana amasankhidwa kuti awonjezere chiwerengero cha mtengo wa optical device.
Mapeto ake: GPON ndiyabwino kuposa EPON.
Chigawo chogawanika
Chiŵerengero chogawanika ndi angatiONU(ogwiritsa) amanyamulidwa ndi m'modziOLTdoko (ofesi).
Muyezo wa EPON umatanthawuza kugawanika kwa 1:32.
Muyezo wa GPON umatanthawuza kugawanika kwa chiŵerengero cha 1:32; 1:64; 1:128
M'malo mwake, machitidwe aukadaulo a EPON amathanso kukwaniritsa magawo apamwamba kwambiri, monga 1:64, 1:128, EPON control protocol imatha kuthandizira zambiri.ONU.Chiwerengero chamsewu chimakhala chochepa kwambiri ndi machitidwe a mawonekedwe a optical module, ndipo kugawanika kwakukulu kumapangitsa kuti mtengo wa optical module ukhale wokwera kwambiri. Kuphatikiza apo, kutayika kwa PON ndi 15 mpaka 18 dB, ndipo kugawanika kwakukulu kumachepetsa mtunda wotumizira. Kuchulukirachulukira kwa ogwiritsa ntchito ndi mtengo wagawo lalikulu logawanika.
Mapeto ake: GPON imapereka zosankha zingapo, koma kulingalira mtengo sikukuwonekera. Kutalika kwakukulu kwa thupi komwe dongosolo la GPON lingathe kuthandizira. Pamene chiŵerengero chogawanika cha kuwala ndi 1:16, kutalika kwa thupi kwa 20km kuyenera kuthandizidwa. Pamene chiŵerengero chogawanika cha kuwala ndi 1:32, kutalika kwa thupi kwa 10km kuyenera kuthandizidwa. EPON ndi chimodzimodzi,chiganizo ichi: wofanana.
QOS (Quality of Service)
EPON imawonjezera MPCP ya 64-byte(multi point control protocol) ku mutu wa MAC Ethaneti.MPCP imawongolera mwayi wofikira ku P2MP point-to-multipoint topology kudzera mu mauthenga, makina a boma, ndi zowerengera nthawi kuti agwiritse ntchito DBA dynamic bandwidth allocation. kugawa kwaONUmipata kufala nthawi, kupeza basi ndi kujowina waONU, ndi lipoti la kusokonekera kwa zigawo zapamwamba kuti agawire bandwidth.MPCP imapereka chithandizo chofunikira pa topology ya P2MP. Komabe, protocol siyimayika zofunikira zautumiki. Ntchito zonse zimapikisana mwachisawawa pa bandwidth. GPON ili ndi DBA yathunthu komanso luso labwino kwambiri la QoS.
GPON imagawa njira yogawa bandwidth m'mitundu inayi. Chofunika kwambiri ndi chokhazikika (chokhazikika), Chotsimikizika, Chosatsimikizika, ndi BestEffort. DBA imatanthauziranso chotengera cha traffic (T-CONT) ngati gawo lowongolera magalimoto, ndipo T-CONT iliyonse imadziwika ndi Alloc-ID. T-CONT iliyonse imatha kukhala ndi GEMPort-IDs imodzi kapena zingapo.T-CONT imagawidwa m'mitundu isanu ya mautumiki. Mitundu yosiyanasiyana ya T-CONTs ili ndi mitundu yosiyanasiyana ya kugawa kwa bandwidth, yomwe imatha kukwaniritsa zofunikira zosiyanasiyana za QoS za maulendo osiyanasiyana a utumiki chifukwa cha kuchedwa, jitter, ndi paketi yotayika. gawo lokhazikika la bandwidth (lokhazikika), loyenera kwa mautumiki ochedwa, monga mautumiki a mawu. Mtundu wa 2 umadziwika ndi bandwidth yokhazikika koma nthawi yosadziwika. Kugawika kogwirizana kotsimikizika kwa bandwidth (Kutsimikizika) ndikoyenera kwa mautumiki okhazikika a bandwidth omwe safuna ma jitter apamwamba, monga kanema pakufunika. Mtundu wa 3 umadziwika ndi chitsimikizo chochepa cha bandwidth ndi kugawana kwamphamvu kwa bandwidth yowonjezereka, ndipo ili ndi cholepheretsa chapamwamba kwambiri, chofanana ndi kugawika kosatsimikizika (Non-Assured), koyenera kwa mautumiki omwe ali ndi zofunikira zotsimikizira ntchito ndi kuphulika kwakukulu kwa magalimoto. Monga kutsitsa bizinesi.Mtundu wa 4 umadziwika ndi BestEffort, palibe chitsimikizo cha bandwidth, choyenera kwa mautumiki omwe ali ndi latency yochepa ndi zofunikira za jitter, monga ntchito yosakatula pa WEB. Mtundu wa 5 ndi mtundu wophatikizika, mutatha kugawa bandwidth yotsimikizika komanso yosatsimikizika, zowonjezera Zofunikira za bandwidth zimaperekedwa momwe zingathere.
Kutsiliza: GPON ndiyabwino kuposa EPON
Gwirani ntchito ndi kukonza OAM
EPON ilibe chidwi chochuluka pa OAM, koma imangotanthauzira za vuto lakutali la ONT, loopback ndi kuyang'anira ulalo, ndipo ndi chithandizo chosankha.
GPON imatanthawuza PLOAM (PhysicalLayerOAM) pamtundu wa thupi, ndipo OMCI (ONTManagementandControlInterface) imatanthauzidwa pamwamba kuti ipange kasamalidwe ka OAM pamagulu angapo.PLOAM imagwiritsidwa ntchito pogwiritsira ntchito kubisa deta, kuzindikira mawonekedwe, ndi kuyang'anira zolakwika. Protocol ya njira ya OMCI imagwiritsidwa ntchito kuyang'anira ntchito zomwe zimatanthauzidwa ndi gawo lapamwamba, kuphatikizapo magawo a ntchito yaONU, mtundu ndi kuchuluka kwa ntchito ya T-CONT, magawo a QoS, chidziwitso chokonzekera zopempha ndi ziwerengero zogwirira ntchito, ndikudziwitsani zomwe zikuchitika mu dongosolo kuti agwiritse ntchito kasinthidwe.OLTku ONT. Kuwongolera zolakwika, magwiridwe antchito ndi chitetezo.
Kutsiliza: GPON ndiyabwino kuposa EPON
Link layer encapsulation ndi multi-service support
Monga momwe tawonetsera pa Chithunzi 2, EPON ikutsatira ndondomeko ya data ya Efaneti yosavuta, koma imawonjezera 64-byte MPCP point-to-multipoint control protocol ku mutu wa Ethernet kuti igwiritse ntchito kugawa kwa bandiwifi, bandwidth-robin, ndi zodziwikiratu mu dongosolo la EPON. Kuthamanga ndi ntchito zina. Palibe kafukufuku wochuluka wokhudzana ndi chithandizo cha mautumiki kupatula ntchito za data (monga ma synchronization services a TDM). Ogulitsa ambiri a EPON apanga zinthu zina zomwe sizili zokhazikika kuti athetse vutoli, koma sizoyenera ndipo ndizovuta kukwaniritsa zofunikira za QoS.
Chithunzi 2: Kuyerekeza kwa GPON ndi EPON protocol stacks
GPON idakhazikitsidwa pagawo la New Transport Convergence (TC), lomwe limatha kumaliza kusinthika kwa mautumiki apamwamba kwambiri. Monga momwe tawonetsera pa Chithunzi 2, imatanthawuza kutsekemera kwa ATM ndi GFP encapsulation (general framing protocol). Mukhoza kusankha zonse ziwiri. Imodzi ndi ya encapsulation ya bizinesi. Poganizira kutchuka kwaposachedwa kwa mapulogalamu a ATM, GPON yomwe imangothandizira GFP encapsulation ilipo. Chipangizo cha lite chidakhalapo, ndikuchotsa ATM ku stack ya protocol kuti muchepetse ndalama.
GFP ndi generic link layer layer for multiple services, yomwe imatanthauzidwa ndi ITU monga G. 7041. Zosintha zochepa zinapangidwa ku GFP ku GPON, ndipo PortID inayambitsidwa pamutu wa GFP frame kuti ithandizire ma multiplexing madoko ambiri. Chiwonetsero cha magawo a Frag (Chidutswa) chimayambitsidwanso kuti chiwonjezeke bandwidth yogwira bwino ya dongosolo. Ndipo imangogwirizira njira yosinthira deta ya data yosiyana kutalika ndipo sichigwirizana ndi njira yowonetsera poyera pamakina a data. GPON ili ndi mphamvu zonyamula ntchito zambiri. GPON's TC wosanjikiza kwenikweni ndi synchronous, ntchito muyezo 8 kHz (125μm) mafelemu autali osasunthika, omwe amalola GPON kuthandizira nthawi yotsiriza mpaka kumapeto ndi ntchito zina zofananira, makamaka zothandizira mwachindunji mautumiki a TDM, otchedwa NativeTDM. GPON ili ndi chithandizo "chachilengedwe" cha ntchito za TDM.
Mapeto ake: Gulu la TC lothandizira GPON pazantchito zambiri ndi lamphamvu kuposa MPCP ya EPON.
Mapeto
EPON ndi GPON ali ndi zabwino zawo. GPON ndi yabwino kuposa EPON malinga ndi zizindikiro za ntchito. Komabe, EPON ili ndi mwayi wanthawi komanso mtengo wake. GPON ikugwira ntchito. Kuyang'ana msika wam'tsogolo wamsika wa Broadband sungakhale wolowa m'malo, uyenera kukhala wowonjezera. Kwa bandwidth, mautumiki ambiri, QoS yapamwamba ndi zofunikira za chitetezo, ndi teknoloji ya ATM monga kasitomala wamsana, GPON idzakhala yoyenera. Kwa makasitomala omwe ali ndi chidwi chotsika mtengo, QoS ndi zofunikira zachitetezo, EPON yakhala chinthu chachikulu.