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In this article, we will explore the key characteristics of different cloud service models and their limitations. Treat this article as a useful brief summary for those looking for a brief introduction to what types of cloud services exist and how they differ from one another.

Key characteristics of this cloud service model are:

  • Vendors deliver the application to their users, over the internet. The applications are typically run through the users’ web browsers.
  • Users do not need to install, manage or upgrade the software — the vendor does it for them.
  • Data is securely stored in the cloud.
  • Examples: Dropbox, Salesforce, etc.

Key limitations of this cloud service model include:

  • There could be integration problems between the software and the users’ own existing apps.
  • Vendors would nearly always find ways for you to stay as their client — e.g. they could apply limitations or extra costs to transferring your data elsewhere.
  • Security of data could potentially be compromised, as you are transferring data to a point you cannot control.
  • Customization can be tricky — usually some common sets of services are provided without paying regard to the users’ individual needs.

Key characteristics of this cloud service model are:

  • Vendors provide a cloud environment (hardware and software) for their users, which they can use to develop, test and host their applications.
  • Users do not need to worry about the underlying infrastructure, and can focus just on the development of their product.
  • All data security and backup issues, as well as operating systems and software updates, are managed by the providers.
  • Usually delivered via web, as well. Multiple users can access at the same time (multi-tenancy).
  • It is built on virtualization technology.
  • Examples: AWS Elastic Beanstalk, Azure, Apache Stratos, etc.

Key limitations of this cloud service model include:

  • There might be complexity in trying to connect the cloud environment with the users’ own on-premise data.
  • Vendors can make it hard to migrate to a different environment — so, you are effectively locked-in and will have to endure a costly process to switch the provider.
  • Customization can be limited, especially if you’re migrating an on-premise application delivered with an already specific environment, to the cloud, which may not have all the requirements satisfied.

Key characteristics of this cloud service model are:

  • Vendors provide access to servers, storage and networking. It’s a self-service model on a pay-as-you-go basis.
  • The resources are scalable — can be provided on demand.
  • Users do not need to buy or maintain their own hardware. Also, they still have control over the resources they are using (no need for external IT contractors).
  • Examples: AWS, Azure, Google Compute Engine, etc.

Key limitations of this cloud service model include:

  • The system can still be vulnerable to possible exposure of the data communication between the host and the virtual machines to some third-party.
  • The users have to learn how to manage the infrastructure on the cloud. They have to learn how to monitor and effectively manage the resources.
  • The provider needs to isolate VMs in a way that new users cannot access the data of the previous users — which can be tricky.

Computer Science & Data Analytics Master Student @ADA & @GWU