Handling redundancy events

After binding to an MTP 3 user SAP, the application receives a MTP3RUNSTATEIND event indicating the redundancy state of the MTP 3 layer on the board. The event type associated with this event indicates one of the following states:

Event type

Description

SN_HAST_STANDALONE

Application is in a non-redundant configuration; normal operation can begin.

SN_HAST_PRIMARY

MTP 3 task on this board is currently the primary board in a redundant board pair; normal operation is allowed as long as the board remains the primary.

SN_HAST_BACKUP

MTP 3 task on this board is currently the backup board in a redundant board pair, monitoring the status of the primary; no active traffic passes through this SAP until the board becomes the primary member of the pair.


The MTP3RUNSTATEIND event is the first message posted to the application queue for each SAP after the binding is confirmed. No data traffic (unitdata or connections requests) should be directed to this SAP until this event is received.

See the SS7 Health Management Developer's Reference Manual for details on writing redundant MTP 3 applications.