Predict end-user response times before deployment. Troubleshoot performance problems throughout an application's development cycle. WebBoy monitors web traffic statistics such as URLs accessed, cache hit ratios, Internet protocols, and user defined protocols. This allows it to measure throughput independently of the TCP implemention of end hosts and to serve as a useful platform for prototyping TCP changes. Has spawned many variants, recent ones include support for UDP, data pattern generation, page alignment, and even alignment offset control.
Source is freely downloadable.
The use of a high precision timer which provides finer granularity timing of the probe packets The ability to change the priority of the process which also facilitates accurate timing Uses packet-pair comparisons to compute bandwidth and congestion. A reimplementation of pathchar. Source freely downloadable. It can be used on user's workstations, or on FreeBSD machines acting as routers or bridges. It can simulate or passively collect network traffic, and can also actively probe the network using a packet-pair 'tailgating' technique.