sentences:  While intrusion detection is mostly concerned about the identification of incoming attacks (intrusion attempts), extrusion detection systems try to prevent attacks from being launched in the first place.They implement monitoring controls at leaf nodes of the network—rather than concentrating them at choke points, e.g., routers—in order to distribute the inspection workload and to take advantage of the visibility a system has of its own state.The ultimate goal of extrusion detection is to identify attack attempts launched from an already compromised system in order to prevent them from reaching their target, hereby containing the impact of the threat.