Free asithappens software for linux

AsItHappens is a real-time network performance monitor. AsItHappens project collects data from devices over a network and displays them on a graph, optionally storing collected data in a database for later retrieval.
Current collection types include network response, bandwidth, Cisco NBAR, and Cisco NetFlow. AsItHappens polls data in regular intervals, which can be as low as every second, to give immediate feedback on network performance.
Main features:
- Granular collection of data to the point of collecting every second
- Real-time graphing of collected data
- Response data collection via ICMP or TCP/UDP echo
- Inbound and outbound bandwidth data collection via SNMP
- Cisco NBAR (Network-based Application Recognition) Top-N collection via SNMP
- Cisco NetFlow Top-N collection via SNMP with flow grouping and match criteria options
- Optional database storage of collection sessions
- Retrieval of user-defined time intervals within a stored collection session
- Resizable graphing window with automatic scaling of graph data to fit
- Options to define how to aggregate or interpolate data when graphing e.g. to show maximums instead of averages
- The ability to add text labels to the graphing panel to explain desired areas of the graph