A popular, configurable, software development process. Unified Process is an iterative and incremental process, component-based, driven by the use cases, and centred on the architecture. It uses UML for design and documentation. A key feature of UP is the production of models, each of which relates to a key stage in the design. One of the best-known UP frameworks is RUP (Rational UP), developed by Rational Software, one of the principal actors in the development of Unified Process. Other UP frameworks include 2TUP (2 Track UP) and AUP (Agile UP).