| 摘要 |
PROBLEM TO BE SOLVED: To prevent loss of down frames at switching to an OSU of an auxiliary system in an OLT without increasing capacity of a downlink buffer.SOLUTION: In each OSU, a built-in downlink buffer can be configured selectively as a batch queue shared by a plurality of subscriber side devices or an individual queue for each subscriber side device, by receiving control from the exterior. An OLT comprises queue configuration control means, in the case that a certain OSU is activated as an OSU for an auxiliary system in standby, making its downlink buffer be configured as the batch queue and detecting reduction in a storage amount of the downlink buffer after protection switching to rearrange the downlink buffer as the individual queue. In the case that the other OSU is activated as an OSU for an active system, the queue configuration control means makes its downlink buffer be configured as the individual queue. |
