Alarm consumer

An alarm consumer:

• Provides the Distributed Alarm system with a set of queries identifying alarmable items about which it wishes to receive notifications. A query remains active until changed or removed by the alarm consumer, and specifies an alarm provider or group of alarms - much like a SQL query with "wildcards." Whenever an alarm provider issues notification of a change, the Distributed Alarm system checks the alarm for matches with all registered queries and passes updates to the corresponding alarm consumers.

• Upon receiving updates, shows or logs information relating to the status of the items or their transitions.

• Acknowledges alarms. The alarm consumer sends an acknowledgement notification to the Distributed Alarm system, identifying the alarm and the alarm provider. The notification is passed to the alarm provider, which then updates the status of the item to acknowledged (if appropriate) and in turn notifies the Distributed Alarm system, thereby ensuring that the update gets distributed to all interested alarm consumers.

  Note: The majority of communication in the Distributed Alarm system consists of sending alarm queries and alarm records from one node to another. Within a node, alarm queries and alarm records are tracked and buffered by the internal alarm memory to minimize network traffic.