A-7
Cisco Intrusion Prevention System Sensor CLI Configuration Guide for IPS 7.2
OL-29168-01
Appendix A System Architecture
MainApp
Note
In the Cisco IPS, the MainApp can automatically download signature and signature engine
updates from Cisco.com.
Shut down or reboot the operating system
The MainApp responds to the show version command by displaying the following information:
Sensor build versio n
MainApp version
Version of each running application
Version and timestamp of each installed upgrade
Next downgrade version of each installed upgrade
Platform version
Version of sensor build on the other partition
The MainApp also gathers the host statistics and reports the health and security monitoring status.
Event Store
This section describes the Event Store, and contains the following topics:
Understanding the Event Store, page A-7
Event Data Structures, page A-8
IPS Events, page A-9

Understanding the Event Store

Note
The Event Store has a fixed size of 30 MB for all platforms.
Each IPS event is stored in the Event Store with a time stamp and a unique, monotonic, ascending ID.
This time stamp is the primary key used to index the event into the fixed-size, indexed Event Store. When
the circular Event Store has reached its configured size, the oldest event or events are overwritten by the
new event being stored. The SensorApp is the only application that writes alert events into the Event
Store. All applications write log, status, and error events into the Event Store.
The fixed-sized, indexed Event Store allows simple event queries based on the time, type, priority, and
a limited number of user-defined attributes. If each event is assigned a priority of low, medium, or high,
a single event query can specify a list of desired event types, intrusion event priorities, and a time range.