A network information analyzing method is disclosed for determining the status of a network including plural communication apparatuses. The method involves assigning a line identifier to each logical line used for establishing data communication between a transmission terminal and a reception terminal, transmitting from a management apparatus to the communication apparatuses line management code information including the line identifier, controlling each communication apparatus to output the received line management code information to the logical line identified by the line identifier included in the received line management code information, controlling each communication apparatus to extract the line management code information from a transmission signal and transmit a corresponding apparatus identifier and the extracted line management code information to the management apparatus, and analyzing the status of the network at the management apparatus based on the corresponding apparatus identifier and the extracted line management code information received from each communication apparatus.