Components of the Event Receiver
The Event Receiver contains the following components:
The SNMP ListenerCentraSite's SNMPv3 Trap Listener, which supports SNMP4J. This Listener starts automatically when CentraSite starts.
The Intermediate Queue The queue from the SNMP Listener to the Event Processor. This queue decouples the SNMP Listener threads from the Event Processor to improve throughput. The following modes are supported.
FileSystem: Incoming Traps will be stored temporarily in the file system
InMemory: Incoming Traps will be stored temporarily in memory
NoQueue: Incoming Traps will not be stored in any intermediate queue; the SNMP Listener threads will be processed.
The Event Processor The Event Processor (SOALinkSNMPEventsListener) transforms incoming SNMPv3 Traps into an XML file (Events.xml) that complies with the schema in the RuntimeEvents Collection component. The Event Processor transforms an SNMPv3 Trap to the Events.xml file as follows:
1. Determines the Event Type (and Target Type) to which the Trap belongs, and gets the corresponding UUIDs. This involves searching all Event Type-to-Trap mappings in all the defined target types, using the Trap’s OID. Since this is an expensive search, the Event Type-to-Trap mapping is cached to improve performance.
2. Parses the Trap attributes and obtains: the Service (UUID), the Target (Name), the TimeStamp, and the SessionId. The Processor then searches the registry/repository and obtains the corresponding UUID for the Target Name. This mapping is also cached to improve performance.
3. Collects the remaining attributes from the Trap.
4. Constructs the Events.xml file using the Event Type UUID, Target Type UUID, Service UUID, Target UUID, TimeStamp, SessionId, and other collected attributes.
The Batch Condition The Batch Condition is a set of OR conditions used by the Event Processor. The Event Processor supports two modes of event storage into CentraSite: BatchMode and NoBatchMode. BatchMode is available only for FileSystem and InMemory queues. When BatchMode is enabled, the Event Processor continues to accumulate Events.xml documents until one of the conditions is evaluated as true. Then it inserts all the documents as a single batch into CentraSite.
The RuntimeEvents Collection The run-time events are stored in the RuntimeEvents Collection as non-registry objects. For information about how events are stored, see
Event Type Modeling.
