1. A method of creating network traffic replicating activities of a large number of users comprising: receiving a test script including a plurality of commands specifying extended operations of an operating system invoking a script interpreter launching an application thread to execute the test script, wherein the application thread is a light weight thread capable of invoking the extended operations, the application thread requiring a smaller amount of memory, less processor power, and less communication with the operating system when compared to traditional threads invoking a protocol engine for each of the commands in the test script such that each protocol engine has an associated command, each protocol engine executing its associated command.