An Optical Distribution Network (ODN) is the passive fiber infrastructure that connects the Optical Line Terminal (OLT) in the central office to the Optical Network Unit (ONU/ONT) at the subscriber side. Unlike active equipment, the ODN does not require electrical power. To date, most FTTH deployments in planning. ODN, or Optical Distribution Network, is an FTTH network based on PON equipment that provides an optical transmission channel between the OLT and the ONU. It directly. There are two major current PON standards: Gigabit Passive Optical Network (GPON) and Ethernet Passive Optical Network (EPON). But no matter which type of PONs, they have a same basic topology structure.