Message routing

Message routing permits the application program to send an output message to one or more terminals not in direct control of the transaction. The message is automatically sent to a terminal if the terminal status allows reception of the message. If a terminal is not immediately eligible to receive the message, the message is preserved for that terminal until a change in terminal status allows it to be sent. The message routing function is used by the CICS® message-switching transaction.

A BMS map that specifies extended attributes can be used for terminals that do not support extended attributes. When sending data to a variety of terminals, some of the terminals may support extended attributes and others may not. When a BMS ROUTE request is processed, BMS looks at the TCTTEs for all specified terminals and constructs a set of all the supported attributes.

A data stream is produced by BMS using this set of attributes, and the data stream and set of attributes for each page are written to a temporary-storage record. When the page is later read from temporary storage, the data stream for each terminal is modified, if necessary, to delete attributes not supported by that terminal.