Method for performing a congestion control in an optical network with multicast data transmission

摘要

Congestion caused by a large number of IGMP requests sent from set top boxes at channel switching is prevented in an optical line terminal (OLT). An IGMP processing section in the OLT has a delayed data generation threshold and a delayed data transmission threshold. When the number of ONTS participating in a multicast group is increased, the OLT generates a delayed multicast group for video data. The delayed multicast group having a few second delay accommodates a new user. With this, the end time of a highly popular program and a commercial start time are shifted among users to prevent, in the OLT, congestion caused by IGMP requests sent for channel switching at an identical time point.