Abstract: It is provided an optical access system, comprising an optical line terminal which is coupled to another network and optical network units which are coupled to the optical line terminal and to a plurality of user terminals. Each of the optical network units obtains a capacity of a buffer included in the each of the optical network unit and a link speed between the each of the optical network units and one of the plurality of user terminals that is coupled to the each of the optical network units; determines a sleep time based on the obtained capacity and the obtained link speed in a case where no communication frames are transmitted for a given period of time from any one of the plurality of user terminals and the optical line terminal; and sets in a sleep state for the determined sleep time.

Abstract: The longest possible sleep time is selected while data missing is prevented in a PON system by referring to the link speeds and the queue buffer capacities of an OLT and ONUs. The OLT calculates a first sleep time candidate based on a first link speed at which the OLT communicates with an upper network and the capacity of an unused area of a first queue buffer where downstream data is held for each of the destination ONUs. Each of the ONUs calculates a second sleep time candidate based on a second link speed at which each of the ONUs communicates with a communication terminal and the capacity of an unused area of a second queue buffer where upstream data bound for the OLT is held. The smaller sleep time is determined and used to change one of the ONUs to a sleep mode.

Abstract: It is provided an optical access system, comprising an optical line terminal which is coupled to another network and optical network units which are coupled to the optical line terminal and to a plurality of user terminals. Each of the optical network units obtains a capacity of a buffer included in the each of the optical network unit and a link speed between the each of the optical network units and one of the plurality of user terminals that is coupled to the each of the optical network units; determines a sleep time based on the obtained capacity and the obtained link speed in a case where no communication frames are transmitted for a given period of time from any one of the plurality of user terminals and the optical line terminal; and sets in a sleep state for the determined sleep time.

Abstract: The longest possible sleep time is selected while data missing is prevented in a PON system by referring to the link speeds and the queue buffer capacities of an OLT and ONUs. The OLT calculates a first sleep time candidate based on a first link speed at which the OLT communicates with an upper network and the capacity of an unused area of a first queue buffer where downstream data is held for each of the destination ONUs. Each of the ONUs calculates a second sleep time candidate based on a second link speed at which each of the ONUs communicates with a communication terminal and the capacity of an unused area of a second queue buffer where upstream data bound for the OLT is held. The smaller sleep time is determined and used to change one of the ONUs to a sleep mode.