Module 05: Architecture, Part 05: Layered Architecture

Summary

The video script discusses layered architecture, a system structuring method with distinct layers like user interface, authentication, business logic, and database. It emphasizes the top-down communication rule, where upper layers only interact with the immediate lower one, facilitating security enhancements and system extensions. However, it also points out performance issues due to the sequential request processing and the practical challenge of maintaining a pure layered approach without layer skipping.

Takeaways

• 🏛️ Layered architecture is a system structure where components are stacked in layers, each serving a specific purpose.
• 🔒 Security is enhanced by the ability to add security layers at various points in the system, such as database protection or firewalls.
• 🛠️ The architecture allows for easy system extension by inserting new layers without altering the existing system, as long as the communication interface remains consistent.
• 🔄 The communication in layered architecture is strictly top-down, with upper layers only communicating with the layer directly below them.
• 🚫 Lower layers in the architecture do not initiate communication with upper layers; they only respond to inputs from above.
• 🛑 A request from the user interface (UI) must pass through each layer sequentially, such as authentication, business logic, and then to the database.
• 👥 Teams can be structured according to the layers, such as UI, security, business logic, and database teams, facilitating specialized focus within each team.
• ⚠️ Performance can be a concern in layered architectures due to the sequential nature of requests, which can be time-consuming if not efficiently implemented.
• 🔄 In practice, it's challenging to maintain a pure layered style without layer-skipping calls, which can complicate design.
• 🔄 The architecture facilitates easy replacement of outdated components, such as authentication systems, without affecting the rest of the system.
• 🔑 The layered architecture is a common and popular style for structuring systems and teams due to its flexibility and modularity.

Q & A

What is layered architecture in the context of system design?

Layered architecture is a system design approach where components are stacked in layers, each with a specific function, and communication between layers is restricted to the layer immediately above or below.

How does the communication work in a layered architecture?

In layered architecture, the upper layers communicate only with the layer directly below them, and lower layers do not call up to the upper layers but only respond to requests from above.

What are some typical layers found in a layered architecture system?

Common layers include the user interface, authentication, authorization, business logic, and lower-level components like the operating system or database.

How does layered architecture facilitate team structuring in an organization?

Layered architecture allows for the organization to be divided into teams based on the layers, such as a UI team, a security team for authentication, a business logic team, and a database team.

What are the security benefits of using layered architecture?

Layered architecture makes it easier to add security features at multiple levels, as new security layers can be inserted without affecting other parts of the system.

Why is layered architecture considered easy for extending or building upon an existing system?

It is easy to extend or build upon an existing system with layered architecture because inserting a new layer that communicates in the same way as the existing layers does not require changes to the rest of the system.

What performance issues can arise from using layered architecture?

Performance issues can arise due to the requirement for requests to pass through all layers, which can be time-consuming if there are many layers or if one layer is inefficient.

Why is it difficult to maintain a pure layered architecture in practice?

In practice, it's challenging to avoid 'jumping over' calls between layers, making it difficult to design a system that strictly adheres to the top-down communication rule of layered architecture.

What is another advantage of layered architecture in terms of system maintenance?

Layered architecture allows for easy replacement of outdated components, such as authentication systems, by simply inserting a new layer without altering the rest of the system.

Can you provide an example of how a request is processed in a layered architecture?

If the UI needs something from the database, the request would go through the authentication layer, then to the business logic layer, and finally to the database, before the response is sent back up the layers.

What is the main challenge in designing a layered architecture system?

The main challenge is ensuring that all layers communicate correctly without skipping any, which requires careful design to avoid performance issues and maintain the integrity of the architecture.