When it comes to a layering strategy, rules must be defined for how the layers will interact with each other. The main reasons for specifying interaction rules are to minimize dependencies and eliminating circular references. For example, if two layers each have a dependency on components in the other layer, then circular dependencies will be introduced.
Only implement top-down interaction. Higher-level layers can interact with the layers below them, but a lower level layer should never interact with the layers above.
Implement a rule that will help you avoid circular dependencies between layers. Events can be used to make components in higher layers aware of changes in lower layers without introducing dependencies.