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Adopting a 4-tier architecture for mobile solutions

Developers have depended on the 3-tier architecture for Web applications, but now mobile demands a new, 4-tier architecture. Matthew David discusses what to know about 4-tier.

Is it time for 4-tier architecture? Here we explore why this new architectural approach may be the key to enabling...

a mobile-first enterprise and how to build this type of architecture successfully.

Once upon a time, all architecture was 3-tier. This worked for Windows solutions and for the Web. Now, let's fast forward from the mid-00s -- a mobile first world. The fairy tale of 3-tier architecture has to change to adapt to a 4-tier architecture.

The basis for a 3-tier architecture is built on the following:

  • Client: Web or desktop software.
  • Services: The tools to connect the data and client together such as J2EE, .NET and PHP.
  • Data: The core system of record where the data is stored.

A mobile-first architecture introduces new challenges that 3-tier did not have to contend with, such as:

  • Client: Device types that have a broad range of power -- from cutting edge iPhones to sensors for IoT solutions.
  • Delivery: A 3-tier world was built on dedicated, physically connected PCs and servers. The mobile first world is plagued with network protocols and speeds that range from blazing fast LTE to range limited solutions like BlueTooth LE.
  • Aggregation: A key differentiator between last decade's PC-centric world and the mobile world of today is the sheer number of mobile devices. Today, there are literally billions of internet connected devices, and estimates from companies such as Ericsson have the number of connected devices increasing to tens of billions before the end of the decade. Services, such as APIs and microservices, must scale much faster and more reliably.
  • Services: Today's system of record has changed. Data is stored behind company firewalls, cloud and in a mix of the two.

The four challenges listed above -- client, delivery, aggregation and services -- are the foundation for the modern 4-tier mobile-first architecture that is being used by companies such as Netflix, Facebook and Uber.

Why use a 4-tier architecture?

The goal for building out a 4-tier architecture is, essentially, the same as the 3-tier architecture: keep the construction of business solutions simple, scalable and maintainable. Teams can be formed to focus on each tier.

The focus of the first tier: Mobile

The mobile client is, in many ways, the easiest to understand for a 4-tier architecture. It's your phone, right? Well, yes and no. The mobile tier is split into devices and operating systems. So you have the following:

  • Mobile devices include phones, tablets, in-car systems, smart TVs, wearables and virtual reality devices.
  • Operating Systems include iOS and Android for phone and tablet; WatchOS, Android Wear, Microsoft Band and Tizen for wearables; tvOS, Android TV, ChromeCast, and WebOS for smart TVs; CarPlay, Android Auto, Windows Auto, Ford Lync and QNX for Smart Cars; and HoloLens, Oculus and Android Cardboard for virtual reality.

What becomes clear is that the mobile first space is crowded and will continue to become even more crowded as core technology such as system on chip (SOC) becomes cheaper and smaller.

The focus of the second tier: Delivery

The world of fixed network connections is gone. Think about it: When did you last plug an Ethernet cable into something? The focus for the second tier is the networks and protocols used to connect data with devices. The following are "delivery" technologies:

  • Wi-Fi: The good news with Wi-Fi is that most locations now have it. What is getting even better is that the latest version of Wi-Fi, AC, is now standard for most networks, allowing for fast connectivity.
  • LTE: There is a lot of talk about LTE. The challenge is that there are more than 20 different implementations of LTE, which is why there is no universal phone today.
  • 3G: Much of the USA still can only connect at speeds of 3G -- approximately 0.5-1.5 Mb per second.
  • 2G: Many emerging countries are still only powered on 2G -- approximately 40-50 Kbps, or the same speed as your 1990's 52 Kbps modem. Facebook recently introduced "2G Tuesday" so developers can experience the same network speeds Facebook customers in Africa use.
  • BTLE: BlueTooth LE is a modified version of BlueTooth 3.0 designed for low power devices. Both Apple and Google have modified versions of BTLE for home networks.
  • Zigbee: Very low powered communication protocol for IoT.

The reason for understanding how each of these communication protocols work comes into how well the data is managed from your mobile devices. Consider including tools that test networks all the way from your client to your data center.

The focus of the third tier: Aggregation

The goal of the aggregation layer is to give solutions the ability to scale in a world with billions of requests. Aggregation falls into the following categories:

  • Data federation: Aggregation of the services tier.
  • Discovery: Define how services will be discovered through using technologies such as APIs and microservices.
  • Protocol translation: The success of APIs is their ability to be used by many different clients. Leading protocols include SOAP, JSON and OData.

Meeting the goals of the third tier will ensure that teams can build solutions using managed and scalable tools to aggregate access to systems of record services.

The focus of the fourth tier: Services

The final tier is where the data for a corporation exists. The following are locations where system of record data can exist:

  • Data centers
  • Public cloud
  • Private cloud
  • Hybrid cloud

In many ways, the final tier is the one that is most familiar to 3-tier architecture: the system of record has always been in a private data center or in a SaaS solution. The challenge is now to ensure that the size of the centers holding the data can quickly reach the customer.

The elements of a 4-tier architecture put in place the tools needed for companies moving from supporting millions to billions of requests.

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