The communication method used by the TCP/IP communication facility provided by TP1/Client/J differs depending on whether the CUP is operating as a client-type or a server-type program. If the CUP is operating as a client-type program, the TCP/IP communication facility establishes a connection from the CUP to the remote system as specified by definitions and parameters. If the CUP is operating as a server-type program, the facility waits for a remote system to establish a connection on the port that is defined in the definitions before initiating communication. Once a connection has been established, the facility sends and receives data in the area specified by the parameter.

Note

Use of the TCP/IP communication facility enables communication with MHPs. In this manual, the remote system is referred to as an MHP, but the user is free to select anything, not only an MHP.

Communication of messages using the TCP/IP communication facility can take any of the following three forms:

• Unidirectional sending of messages from a CUP to an MHP
• Unidirectional receiving of messages from an MHP to a CUP
• Bidirectional sending and receiving of messages between an MHP and a CUP

Organization of this section

2.4.1 Unidirectional sending of messages

2.4.2 Unidirectional receiving of messages

2.4.3 Bidirectional sending and receiving of messages

2.4.4 Received message assembly facility

2.4.5 Notes about using the TCP/IP communication facility