Exception handling

Connected versus disconnected detection

The TCH connector monitors echo messages as heartbeats to and from TCH. If no traffic is received for enough cycles, the connection is considered to be offline. The connector stops communicating over the connection and does not process any request from FTM The Clearing House Real Time Payments on that line while the connection is offline.

If all connectors are disconnected from TCH, only SignOn request messages from FTM The Clearing House Real Time Payments are fetched from the RequestToCSM queue. When no messages are fetched, transactions fail because their related messages to TCH are expired.

When the connector detects a change in its connection status, it builds and sends IBM® MQ internal system notification messages with event code 111 to IBM MQ. These messages allow the scheduling task that is configured for this particular connector to track the correct status. Disconnected states are reported as alerts.

Expired messages

All messages that cannot be processed in a timely manner expire. Any involved processing component, whether it is the FTM The Clearing House Real Time Payments, TCH connector or TCH RTPS, can rely on IBM MQ expiration and only new messages from active immediate payment transactions are processed.

Heartbeat messages

To be sure that FTM The Clearing House Real Time Payments can reach the TCH connector component, it expects heartbeat messages at regular intervals. These messages are implemented as internal system notification messages with event code 112. If they are not received in a timely manner, the connector is shown with a state of Unavailable in its related scheduler task. The heartbeat message also contains the information about the status of the connection, so the status that is shown by its related scheduler task is synchronized correctly.