Extending use cases and interaction diagrams to develop distributed system architecture requirements

Current object-oriented development methodologies do not introduce distributed system architectural aspects early enough in the system development cycle. A development partitioning scheme that includes the system level, in addition to the problem and application levels, will encourage analysis that includes elicitation of non-functional system requirements. These requirements include response time with respect to system communication load, fault tolerance, safety, security, and real-time deadlines, among others. They can be documented with an extended form of Jacobson's use cases. Where use cases describe how a system will work from a user's point of view, extended use cases add the capability to describe how well it should work. System level analysis information can be graphically depicted on extended forms of Unified Modeling Language (UML) interaction diagrams and on multilevel architecture diagrams.