The Nokia case is comparable with a normal software product line. During the first phase, product management, it is possible to define the scope of the different mobile-phone series. During the second phase, domain engineering, requirements are defined for the family, and for the individual types of phones, e.g., 6100/8300 series. In this phase, the software requirements are made, which can serve as a base for the whole product family. This speeds the overall development process for the software. The last phase, product engineering, is more focused on the individual types of phones. The requirements from the preceding phase are used to create individual software for the type of phone then being developed.