Remote destination verification
To maintain system integrity and prevent errors, an IMS in an MSC network verifies all specified destinations, unless MSC directed routing is used.
When MSC directed routing is used, IMS only
ensures that a program-to-program switch is not being performed from
a nonconversational transaction to a conversational transaction. Remote
destination verification occurs when a message is received from a
terminal or on receipt of an application program reply if a remote
destination is specified for the message. Destination verification
occurs as follows:
- Destination
- Verified For:
- LTERM
- Destination type: The original destination must have been a logical terminal.
- Transaction
- Destination type: The original destination must have been a transaction.
Transaction attributes: The following attributes must be consistent in the transaction definitions in the input and destination systems:
- Single segment or multiple segment
- Recoverable or irrecoverable
- Conversational or nonconversational
- Inquiry or update
The SPA size for a conversation from a remote system cannot be changed except by the remote system on an insert.
When an invalid destination is recognized, IMS cancels the message, sends an error message to the input terminal and to the master terminal of the local system, and logs an invalid request. If the message is conversational, the Conversation Abnormal Termination exit routine (DFSCONE0) is called in the input system, and the conversation is terminated.