Abstract: A session management server, which is provided with a service determination table having a plurality of entries each indicating a service identifier in association with possible particular items of information which may be extracted from a session setup request packet, receives a session setup request packet issued from a client to a particular application server and determines whether the client terminal is authorized to receive an information service by referring to the determination table, in place of the particular application server. When the determination results in success, the session setup request packet is forwarded to the particular application server.

Abstract: A control node includes: a monitoring packet transmission section for transmitting a monitoring packet; a monitoring packet reception section for receiving a monitoring packet; an adjustment section for selecting a redundant node from a non-control nodes; a packet generation section for generating a setup packet for specifying the redundant node out of the non-control nodes in accordance with information about the redundant node selected by the adjustment section; and a packet transmission section for transmitting the setup packet to the non-control node. The non-control node includes a control section that acquires information about the traffic upon receiving the monitoring packet, transmits a monitoring packet after acquisition of the traffic, and specifies the non-control node as the redundant node based on information about the redundant node contained in the setup packet upon receiving the setup packet.

Abstract: A session management server, which is provided with a service determination table having a plurality of entries each indicating a service identifier in association with possible particular items of information which may be extracted from a session setup request packet, receives a session setup request packet issued from a client to a particular application server and determines whether the client terminal is authorized to receive an information service by referring to the determination table, in place of the particular application server. When the determination results in success, the session setup request packet is forwarded to the particular application server.