Using APPC to Communicate with Other Systems › Define APPC Tables › Define a Transaction Control Table

Define a Transaction Control Table

The Transaction Control Table (TCT) is used to define all transactions to your product. Each TCT entry can be used to control allocation requests, attach requests, or both. A conversation cannot proceed without referencing a valid TCT entry.

All transaction identifiers and transaction program names (TPN) must be defined in a TCT to relate each transaction identifier to the appropriate TPN. Therefore, when a program issues an allocation request it uses a transaction identifier to indicate which transaction program it wants to communicate with. The system relates this identifier to the TPN.

The TPN is carried in the attach request sent to the remote domain. At the remote domain attach processing will use the TPN to start the correct program to service the request. The TPN is therefore known to both LUs that are to participate in a conversation. Transaction identifiers are only known locally to each LU.