Workload Generation in OPNET by User Behaviour Modelling

In this paper, a user-behavior oriented workload generator for OPNET is presented. In this novel approach, both packet generation and user interaction with applications and services that cause the network traffic are modeled. This way, the analyst can model traffic and construct a workload at a higher level of abstraction. The user behavior is represented by a user profile, defining a hierarchy of independent processes that exchange standardized messages with each other. Generally, any type of stochastic process can model such processes. In the current implementation, processes are modeled by finite state machines whose states denote the actions a user can perform. A collection of text files defining a process hierarchy is called a user profile. User profiles are stored in a user profile database that is a sub-tree of a Windows or Unix file system. Due to the hierarchical profile structure, it is possible to define user behavior models in a modular manner. This way, new user profiles can easily be constructed by reusing existing (sub-) profiles.