A system that utilizes data over cable service interface specification (DOCSIS) over passive optical networks is disclosed. An example system includes core system in a passive optical network (PON), comprising a memory; and one or more processors configured to generate a downlink (DL) data stream comprising optical signals, in compliance with a data over cable service interface specification (DOCSIS); and provide the optical signals containing DL data to a network component in the PON over an optical fiber coupled between the core system and the network component. In some embodiments, the core system is located at a head end equipment at the internet service provider's facility. However, in other embodiments, the core system can have a distributed architecture, with a part of the core system located at the internet service provider's facility and a different part of the core system located at a different location.