Patent ID: 8724993

Claim:
A station side device comprising: a message processing unit for receiving, via an optical network unit, a report message from a terminal device which, in response to a query message, has sent out the report message according to whether the terminal device keeps belonging to a multicast group or leaves the multicast group so as to update management of the optical network unit having terminal devices each being subordinate thereto and belonging to a multicast group according to said report message, and for outputting message processing capability information; a longest response time calculating unit for dynamically setting up a longest response time which a terminal device can spend until transmitting a report message after receiving a query message according to the message processing capability information outputted from said message processing unit; and a message creating unit for transmitting a query message for querying whether a terminal device belonging to a multicast group continues to belong to the multicast group to said terminal device by way of said optical network unit after including the longest response time set up by said longest response time calculating unit in the query message.