Maintaining Data Integrity

If you want to maintain data integrity while using the high performance transport API, use the following techniques:
  • Put a sequence number on every flow between two applications. If you do this, the receiving application recognizes whether a number is missing and whether an error occurred. After detecting the error, the two applications can resynchronize.
  • Use a start and end message. For example, if the sending application recognizes that it has 50 pieces of data to send, it can:
    • Send a start message indicating that 50 pieces of data exist.
    • Send the 50 pieces of data.
    • Send an end message indicating that the transfer is complete.

    If the application receives start and end messages, but does not receive 50 pieces of data, it recognizes that an error occurred. If the application receives another start message before an end message, it means that an error occurred because the end message is missing from the previous send.

    If the application receives an end message followed by more data, an error has occurred.

  • Specify a time interval within which a response must be received (assuming the request required one). If this time interval passes, the API cancels the request and sends an MDS error message to the other node to specify that the UOWC is no longer outstanding and no reply is required. The MDS error message, which is also sent to the application that generated the request, has a sense code of X'08A90003'.

    You can use the SENSE command to display the meaning of a sense code. Refer to NetView® online help for more information about the SENSE command.