ArcSight's flagship product, the ArcSight Enterprise Security Manager, is a security event management (SEM) tool capable of analyzing large mounts of network data in real time. The IDS model fell down because the flood of unfiltered alerts overwhelmed the resources of security teams, but SEM provides correlation, filtering and analysis to, in theory, allow the few real threats to be picked out of the blizzard of less important alerts and false positives.