Abstract: Even if a communication is interrupted, a communication control module in a data terminal reestablish the communication without informing a communication module that the communication has been interrupted in a case where it is possible to reestablish the communication. The communication control module determines that the communication can be reestablished if the interruption is temporary, or the condition of a network is good. The communication module does not recognize the interruption of the communication if the communication can be reestablished. Therefore, when the communication circuit is reestablished, the data communication is restored retrospectively to the time of the interruption of the communication.

Abstract: Even if a communication is interrupted, a communication control module in a data terminal reestablish the communication without informing a communication module that the communication has been interrupted in a case where it is possible to reestablish the communication. The communication control module determines that the communication can be reestablished if the interruption is temporary, or the condition of a network is good. The communication module does not recognize the interruption of the communication if the communication can be reestablished. Therefore, when the communication circuit is reestablished, the data communication is restored retrospectively to the time of the interruption of the communication.

Abstract: Even if a communication is interrupted, a communication control module in a data terminal reestablish the communication without informing a communication module that the communication has been interrupted in a case where it is possible to reestablish the communication. The communication control module determines that the communication can be reestablished if the interruption is temporary, or the condition of a network is good. The communication module does not recognize the interruption of the communication if the communication can be reestablished. Therefore, when the communication circuit is reestablished, the data communication is restored retrospectively to the time of the interruption of the communication.

Abstract: When a plurality of IP packets to be relayed, which form a TCP connection, pass through a router device, converting units rewrite part of IP address information and port number information within the packets according to a predetermined rule in cooperation with a TCP connection management database. A stream linking unit extracts the information indicating the original connection destination of a TCP connection from the packets, and links two TCP connections with streams. Converting units rewrite part of the IP address information and the port number information within a plurality of packets to form a TCP connection with an original connection destination according to a predetermined rule in cooperation with the management database.

Abstract: LWP 16 obtains a text file from WWW server 14A via Internet 13 and data sizes of image files designated by IMG tag in the text file, and transmits the text file to DTE 11 via Internet 13, gateway server 15 and mobile packet communication network 12 after adding alphanumeric strings according to data sizes to the ALT property values of IMG tag. On DTE 11, ALT property values containing alphanumeric strings according to data sizes are displayed instead of images, which have not been displayed.

Abstract: When a plurality of IP packets to be relayed, which form a TCP connection, pass through a router device, converting units rewrite part of IP address information and port number information within the packets according to a predetermined rule in cooperation with a TCP connection management database. A stream linking unit extracts the information indicating the original connection destination of a TCP connection from the packets, and links two TCP connections with streams. Converting units rewrite part of the IP address information and the port number information within a plurality of packets to form a TCP connection with an original connection destination according to a predetermined rule in cooperation with the management database.