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• 🔄 The architecture facilitates easy replacement of outdated components, such as authentication systems, without affecting the rest of the system.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.

Outlines

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🏛️ Layered Architecture Overview

The script introduces layered architecture as a system structuring method where components are stacked in layers, each serving a specific function. The typical layers include user interface, authentication, authorization, business logic, and underlying systems like databases or operating systems. Communication is strictly vertical, with upper layers only interacting with the immediate lower layer, ensuring a clear separation of concerns. This architecture is beneficial for structuring teams and enhancing security by allowing the addition of protective layers at various points. It also facilitates the easy extension or replacement of system components without disrupting the entire system, provided the interface remains consistent.

Keywords

💡Layered Architecture

Layered architecture is a design approach used in software engineering where a system is divided into a series of layers, each with a specific function. In the context of the video, it is described as having layers such as user interface, authentication, authorization, business logic, and database. This architecture is crucial for structuring a system in a way that each layer communicates only with the one directly beneath it, ensuring a clear separation of concerns and facilitating maintenance and scalability.

💡User Interface (UI)

The user interface, or UI, is the point of interaction between a user and a system. It is the visual and interactive part of a software application. In the script, the UI is mentioned as the topmost layer in a layered architecture, responsible for receiving user inputs and displaying outputs, with requests being passed down to lower layers for processing.

💡Authentication

Authentication is the process of verifying the identity of a user or device. It is a security measure to ensure that only authorized entities can access a system. In the video, the authentication layer is described as a part of the layered architecture that validates user credentials before allowing access to other system resources.

💡Authorization

Authorization refers to the process of granting access and permissions to authenticated users within a system. It is about determining what actions a user is allowed to perform. The script mentions authorization as a layer that comes after authentication, ensuring that users can only access the resources and functionalities they are permitted to use.

💡Business Logic

Business logic is the core part of a software application that encodes the real-world business rules that determine how data can be created, displayed, stored, and changed. In the video, the business logic layer is where the actual functions of the system that perform tasks are located, processing requests from the UI layer and interacting with the database or other services.

💡Database

A database is an organized collection of data, typically stored and accessed electronically. It is a critical component in many software systems for storing and retrieving information. The script describes the database as a part of the layered architecture, usually at the bottom layer, where data persistence and retrieval operations are handled.

💡Operating System

An operating system is the software that manages computer hardware and software resources and provides common services for computer programs. In the context of the video, the operating system is mentioned as one of the lower layers in the architecture that provides foundational services to the application layers above it.

💡Security

Security in the context of the video refers to the measures taken to protect a system from unauthorized access and potential threats. The layered architecture facilitates security by allowing for the addition of security layers at various points, such as database protection or firewalls, to enhance the system's defense mechanisms.

💡Performance

Performance in software architecture refers to the system's efficiency and speed in processing tasks. The script mentions performance as a concern in layered architectures due to the need for requests to pass through multiple layers, which can lead to delays if not implemented efficiently.

💡Extensibility

Extensibility is the ability of a system to be expanded or modified easily. The video script explains that layered architecture is advantageous because it allows for easy extension of the system by adding new layers without altering the existing ones, as long as the communication interface remains consistent.

💡Replaceability

Replaceability is the ease with which components of a system can be replaced with new ones. In the script, it is mentioned as a benefit of layered architecture, where outdated components like an authentication system can be replaced by implementing a new one and inserting it into the appropriate layer without affecting the rest of the system.

Highlights

Layered architecture is a system structuring method where components are stacked in layers.

Each layer communicates only with the layer directly below it, creating a top-down flow.

Typical layers include user interface, authentication, authorization, business logic, and database access.

The layered approach allows for specialized teams to focus on specific system layers.

Security features can be easily added at various levels within the architecture.

New functionalities can be inserted without altering the entire system, as long as the interface remains consistent.

Layered architecture facilitates easy extension and building upon existing systems.

Performance can be a concern due to the sequential nature of request processing through layers.

In practice, maintaining a pure layered style without layer-skipping can be challenging.

Replacing outdated components, such as authentication mechanisms, is theoretically straightforward in layered architecture.

The layered system is a common architectural style for organizing complex systems.

The architecture promotes a clear separation of concerns, enhancing system organization and maintainability.

Each layer is responsible for a specific aspect of the system, contributing to a modular design.

The layered approach can simplify system updates and maintenance by isolating changes to specific layers.

Organizational structure often mirrors the layered architecture, with teams aligned to specific layers.

The layered architecture can be adapted to include additional layers for specialized functions or services.

Despite its benefits, the layered architecture may encounter issues with efficiency and design purity in real-world applications.

Transcripts

next up in our list of uh architectural

styles is the layered architecture and

as the name suggests

we have a number of layers that are on

top of each other

and this is how we structure our system

and

typical layers we might have is for

example the user interface

we might have an authentication

layer

authorization

we might have a business logic so the

actual functions that do something

and we might for example have the

operating system or the database or

other things that come in here

and the way the layered architecture

works is that the upper layers only ever

talk to the layer right

below it so you're not allowed to jump

over that

and the lower layers never call up they

just reply

so if i for example from the ui send an

authentication request to the second

layer this layer answers that but the

layer will never by itself call the ui

and say please do something it's only

reacting to input coming from above so

the way this works is simply that the

requests are trickled down until the

lowest layer for example if the ui needs

something from the database it will

first go through the authentication then

into the business logic then to the

database and back

so this is how the layered architecture

works um

this is a common way to for example

structure teams that you have the ui

team you have the authentication or some

kind of security team you have the

business logic team and database team

you might have multiple of those of

course so depending on how large your

system is you might have a number of

teams here that do work

but this is a very common way of

structuring your organization

now

advantages of the layered architecture

are for example security

so it's rather easy to add security

features at multiple levels so you can

in here for example insert a new layer

that has some kind of protection on the

database or i don't know a firewall

whatever you need but you have these

possibilities to do that at several

levels

um and

well this is a

typical way of inserting things in

general because the interface is fixed

on a more general level not just looking

at security it's very easy to insert

something new without having to change

the system

as long as that layer that i insert in

the middle is kind of using the same way

to communicate

the other two should not care about this

so it should be in theory very easy to

extend or to build on top

of an existing system

so that's why it's a very popular style

to use

there are however

a number of issues here and one of them

is for example that

it's quite difficult to get a nice

performance

because the requests have to go all the

way through they're not allowed to jump

over so this can easily take time if you

have a lot of layers or if one of these

layers is not very efficiently

implemented so performance is often a

concern in these

and in practice

it is actually difficult

to avoid these jumping over calls so

it's difficult to design this in a good

way that

you have a pure layered style where you

only call top down and you don't jump

over layers so in practice it's not that

easy

one thing i forgot to mention it's not

only easy to build on top or add

security layers in between it's also

easy again in theory to replace things

so if you figure out that the

authentication is for example outdated

it should be fairly straightforward to

implement a new one and just put it in

here

without having to change the remaining

system

so that's another

good feature that you can simply take

this out put something else in

and it should work so that's known as uh

the layered architecture or layered

system

and

that's all i want to say for this style

let's continue to the next one