Provided is a network
system including a traffic information aggregating apparatus connected to a
router for transferring data in a network, and a monitor
server connected to the traffic information aggregating apparatus. In the network
system, the traffic information aggregating apparatus receives traffic information from the
router, assigns an aggregation identifier to the received traffic information, creates aggregated information by aggregating the traffic information based on the assigned aggregation identifier and by statistically
processing the traffic information, transmits the created aggregated information and the assigned aggregation identifier to the monitor
server, and retrieves, upon reception of a retrieval request including the aggregation identifier from the monitor
server, requested traffic information from the received traffic information, based on the aggregation identifier included in the received retrieval request. Accordingly, an amount of data received by the monitor server can be reduced.