| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent occurrence of data losses arising from a difference in time between an external buffer activation processing start time on the receive side and a downlink data rate limiting start time on the transmit side. <P>SOLUTION: In an ONU, an activation control unit 28 predicts an estimated value Ne for the stored amount of data and times T1 and T2 at which a measured value Nm reaches a specified value N2, respectively, and calculates a spare capacity ΔN for storing arrived data which is input at ΔT between the times T1 and T2. Then, when at least one of the estimated value Ne and the measured value Nm exceeds a standard value Ns obtained by subtracting the spare capacity ΔN from the specified value Nw, it starts an activation process for placing an external buffer 23 into a usable state. A switching control unit 29 switches the storage destination to the external buffer 23 when the measured value Nm exceeds the specified value Nw and activation of the external buffer 23 is completed. <P>COPYRIGHT: (C)2012,JPO&INPIT |
