How are different levels of testing related to different types of testing?

Levels or stages of testing refers to which testing should be done first or what should be the order of testing once the application is available for validation in testing phase of SDLC. As per the process, Component testing is the first testing, followed by integration testing and system testing and finally acceptance testing.

Types of testing i.e. functional and non-functional testing defines the objective of different testing levels. Let’s say we are doing component testing of a module, then the objective of component testing is if we are testing the functionality of the module or we are focused to test the performance or security part of the module.

So, testing types define the objective of testing phases/levels is we are focused functionally or non-functionally.