Performance considerations for Common Programming Interface Communications

You can use Common Programming Interface Communications (CPI Communications) to write application programs that you want to communicate with advanced program-to-communications (APPC). The interface makes use of the System Network Architecture (SNA) LU (logical unit) 6.2 architecture to do the following:

• Establish a conversation
• Send and receive data
• Exchange control information
• End a conversation
• Notify a partner program of errors.

Intersystem communications feature (ICF) and CPI Communications programs have similar performances for small data transfers.

To optimize CPI Communications application programs, do the following:

• Minimize the use of flush and confirm.
• Receive a compile record and parse it in your buffer.
• Do not use multiple receive calls to receive a single record.
• Use Request-to-Send only when necessary.

To add or change communications entries to get the system set up for CPI Communications, do the following:

1. Type appropriate command on the iSeries™ system command line and press F4.
   • Add Communications Entry (ADDCMNE)
   • Remove Communications Entry (RMVCMNE)
   • Change Communications Entry (CHGCMNE)
2. Use the online help information to change, add, or remove parameter values.
3. Press Enter. The communications entries are added, changed or removed.

For more information about configuring CPI Communications, see:

• Application programming interface (API) performance considerations
• CICS/400® Administration and Operations Guide