Service V Model
Service V Model is a concept that is raised in the Service Transition volume of the new ITIL Version 3.
The Service V Model is a unique concept that provides a path to follow with regard to defining the requirements for a service package, designing the package, building and then testing the package.
The model provides baseline points along the path that are used a checkpoints to ensure that what is being designed, built and delivered is actually what was required. Each step on the path also has specifically named outputs that should be visible.
The V-model is a software development model which can be considered as an extension of the waterfall model. Instead of moving down in a linear way, the process steps are bent upwards after the coding phase, to form the V shape.
The V-Model demonstrates the relationships between each phase of the development life cycle and its associated phase of testing.
During each phase of software development thought is already given to the corresponding tests. For instance, during the definition of the Service Requirements, the corresponding Acceptance tests are already written and signed off.
The advantage of the V-model is that by writing the tests at the time of specification errors in the specifications can be detected in an earlier phase, avoiding costly reworks later on.
Additionally, testing happens at different levels, first component testing, then package testing, system testing etc. again leading to early detection of errors.