The High Level Design Document is a pretty important document for a project, covering at a high level the overall design of the solution. If one were to try and present a very succinct summary of the High Level Document, it could be something like this:
– Detailed use case scenarios of key process flows of the application
– The class model and relationships
– The sequence diagrams which outline key use case scenarios
– The data/object model with relational table design
– User interface style and design
High-level design is the transitional step between WHAT [requirements for sub-systems] the system does,
and HOW [architecture and interfaces] the system will be implemented to meet the system requirements.
This process includes the decomposition of system requirements into alternative project architectures and
then the evaluation of these project architectures for optimum performance, functionality, cost, and other issues
[technical and non-technical]. Stakeholder involvement is critical for this activity. In this step,
internal and external interfaces are identified along with the needed industry standards.
These interfaces are then managed throughout the development process.