Even when session control traffic such as SIP traffic to be unitarily subjected to QoS management by a manager of a session control network such as an SIP network, and loopback traffic to be freely subjected to QoS management by users coexist, QoS processing can be appropriately performed. The edge router checks a routing table and the address information of an SIP message to derive an SIP stream direction. The edge router timely selects a table that can be set by only SIP network managers, and a table that can be set by user network managers as well, determines QoS setting information by collating other SIP/SDP message information, and sets it in a QoS function unit.