Frontend layer of an application

Now, as the name says, frontend means direct customer interaction or what you see on your screen.

We connect to an application through our desktop or any mobile application.

You connect to the application through Internet or intranet, depending upon where you are located and which app you are connecting with.

Most of the applications ask you to authenticate before using them.

This is a way to stop malicious traffic getting into your application network.

Most of the information which you see here will come from CDN.

CDN means content delivery network.

Now the question is what is CDN and why do we have it?

Let's say the application which you are trying to connect with, is a very popular app and there is a high volume of traffic hitting the application continuously.

This means a lot of people will try to access it at the same time, which is going to slow the service performance.

The application users will be globally distributed, which means a lot of time will be spent in data transferred from one part of the globe to another, resulting in the slow application performance.This company make the static content data highly distributed across several locations which will be competitively closer to you.

For example, you are living in Japan and you want to use Gmail, which is coming from Google located in the U.S. The connection of users in Japan will travel to USA and then back to Japan. For every activity that you do the to and fro connection between U.S. and Japan will slow down the performance resulting into bad customer experience.

Thus Google then host its content at some location in Japan so that in spite of connecting to US, you will get your data from somewhere in Japan and Google will continue to have the data replicated at its U.S. location as well to have it centralized stored.

Likewise, Google will have servers located in China, India, Russia, etc. for faster connection of its users across the globe.This is nothing but CDN. Thus in technical terms CDN is highly distributed platform of servers that helps minimize delay in loading web content by reducing the physical distance between servers and user.This helps users around the world view same high quality content without slow loading time.

One very important benefit of CDN is DDoS which is distributed denial of service. Fraudsters try malicious attempt to disrupt the normal traffic off our target date server or network by overwhelming the target or its surrounding infrastructure with a flood of Internet traffic.

If they succeed in penetrating through the application due to a flood of Internet connections, it has the capacity to bring down the entire system. Due to CDN, they will be able to impact only one site or location and your main centralized location will be safe and intact, which is much better than getting the entire system down.

Users in other locations can still use and function BAU.The impact will be comparatively less. Now let's go back to the flow of the frontend layer in an application.After user gets authenticated, they hit the load balancer. The purpose of lowered balance is to distribute the traffic across all web servers of the application.

Based on your application design, the API gateway will further transfer your data to the application

layer through API Gateway.

This is all that happens in the frontend layer. To summarize, it except user connection.

Get the user authenticated and transmit it to the application.