Optical Line Terminal (OLT) Dhexdeedka Networkka Optical Access

Kala goynta iyo kala soosheeda ee OLT (Optical Line Terminal) waa qaybta muhimka ah ee shabakadaha oo ka mid ah shabakada oogla ee pasiivka ah (PONs) oo waxay muujin doontaa in kaa badan ONU (Optical Network Units) ay siin karto OLT kahor kan oo kala goynta oog ee shabakadda, kala soosheeda iyo qiimaha dhaqanida. Wadarta kala goynta (tusaale ahaan, 1:8, 1:16, 1:32, 1:64) waa in kaa badan ONU ay iska wada qabsataa jiidada oog ee jiidada OLT, oo kala goynta sare ay kordhin doontaa in kaa badan oo kala duwan yarayn doontaa jiidada oog ee ay iibsadaa iyo kala duwan badan oo ayabta. Kala goynta wadarta kala soosheeda ee jiidada oog ee maaksimum ee la oggol yahay ee ka dhasha OLT iyo ONU. Bajadaan waxay ka kooban tahay jiidada OLT oo soo saaraya, jiidada ONU oo qaadaya, iyo kala duwan ee kala goynta, khayraadka cabirka, iyo kala duwan ee kuxira. Tusaale ahaan, kala goynta 1:32 ayaa soo jeedaa in kala duwan ugu yara 15.5dB, haddii kala goynta 1:64 ay soo jeeda in kala duwan ugu yara 18.5dB. Muhandisiyada waa inay hubi doonto in kala duwan oo dhammee (kala duwan ee kala goynta + kala duwan ee cabirka + kala duwan ee khayraadka/kuxirka) aan ka yar yahay jiidada oog, taas oo badan ugu yara 28-32dB ee shabakadaha GPON iyo sare sanamka XGS PON (si uu ka yar yahay 35dB). Macluumaadka badan ee macluumaadka waa qayb kale oo muhim ah. Oo kasta oo ONU ay iska wada qabsataa macluumaadka oo dhammee ee OLT (tusaale ahaan, 2.5Gbps hoos ugu dhacnaya GPON), sidaa darteed kala goynta sare ay kordhin doontaa macluumaadka la heli karo koox kasta. Dalka dhexe ee dhexdhexaad (web, dhicitaan) kala goynta 1:32 ayaa hubaal ah, oo soo saaraya ~78Mbps per ONU. Dalka sare ee dhexdhexaad (4K dhicitaan, guriyaha) kala goynta 1:16 ayaa hubaa in kaa badan macluumaadka (~156Mbps per ONU), inkastoo taas ay kordhi doonto qiimaha alaabta sababtoo in kaa badan OLT iyo kala goynta. Ayabta iyo shartiyaasha QoS waa wax kale oo muhim ah. Adeegyada loo qabanayo sawirka iyo wararka sawirka ayaa u baahan yahay ayabta yar, taas oo ayabta sare ay kordhin doontaa sababtoo in ay badan yihiin macluumaadka. Kala goynta macluumaadka dinamiikada (DBA) ee OLT ayaa ka caawi doonta in ay qabsada adeegyada sare, laakiin waxay leeyihiin xadka - kala soosheeda ayaa laga yaabaa in la isticmaalaa kala goynta yar (1:8) dalka ayabta dhaafsan ee dhibka ah.