Network systems and communications equipment

摘要

A duplicate system includes an active side (0 side) and a standby side (1 side). An OLT includes an autodiscovery function (1003) which, when the OLT is active, determines the next starting time of autodiscovery procedure of the standby side and notifies the standby side of the above starting time, a table of management information (1005) that holds the line information of a partner with which the OLT forms the duplicate system and the next starting time of autodiscovery procedure of the OLT, and a function of switching active side (1002) that calculates a timing of switching active side. A function of receiving data from ONT (1004) in the OLT includes a function of detecting data sequence number (1102) and a function of detecting queue length (1101). Moreover, a function of sending data of ONT (803) includes a function of assigning sequence number (901) and a function of discarding data (902).