Types of requirements

Question: What are the different types of requirements? In other words, how would you categorize the different types of requirements?

Response:

Broadly speaking the two types of requirements are:

•          Functional – A functional requirement try to seek answers to what a system needs to do to satisfy the objectives / needs; and
•          Non-Functional – A non-functional requirement try to gather information on how a system needs to do activities to fulfill the functional objectives for ex. security, performance, availability, configuration needs, etc.

Requirements can also be categorized from an architecture point of view such as:

•           Business: How a business work. A very high level view. For example: product and service, financial structure, business processes, etc.
•      Application: Services and functionalities from a end user perspective. Automated and non-automated services.
•           Operations – what the organization needs to run the processes and operations like data management, replication services, security levels, etc.
•          Technology – S/W and infrastructure requirements such as environment, database, security, network and so on.