Application Protocols

The LU 6.2 enables program-to-program communication. The design of your program depends on the protocols that you define and the communication that your program must accomplish.

In addition to any rules that you define for your program, LU 6.2 defines rules that your program must follow when using a conversation. To enforce these rules, LU 6.2 manages the state of your conversation and allows your program to perform certain operations only when the conversation is in the correct state. For example:
  • Your program cannot send data unless it has permission to send.
  • Your program cannot receive data unless the partner program has permission to send.
  • Your program cannot use a conversation after it has been deallocated.

For more information, see the conversation state tables in APPC Conversation State Transitions or refer to Common Programming Interface Communications CPI-C Reference Version 2.0 (SC26–4399) for a complete list of states and permissible operations.

Table 1. Conversation States
State Definition
Reset The conversation does not exist.
Send The program can send data, request confirmation, or deallocate the conversation.
Receive The program can receive information from the partner program.
Confirm The program can reply to a confirmation request.