Load testing, part of the broader work of QA testing and automated testing, involves putting demand on software or devices in order to measure the system’s behavior in normal usage and possible “peak load” scenarios. Sometimes called stress testing, the process is essential for understanding how a system will handle different numbers of simultaneous users. Load testing tools are used to help determine optimal architecture and scale needed to support projected usage...
We mostly use Silk Performer to test the web protocol. I'm the principal software architect and we are users of this product.