Abstract: A testing tool for Internet Service Provider (ISP) network engineers which is used to diagnose network faults, characterize network performance and evaluate new equipment and software releases. The tool can be used to schedule and run proactive tests to identify network problems before subscribers are affected. Further, the tool can be used to provide testing on demand to quickly isolate the root cause of a problem identified by the tool or by network management systems or subscribers. The tool is topology independent and thus does not have to be reconfigured as the network changes. The tool only sends traffic as directed by the network engineer and thus does not generate undesirable heavy network traffic loads, unless such a heavy network loads are desired by the network engineer.