Before getting into the difference, first we need to know what cloud service models is.
What is cloud service model?
Based on the level of flexibility, control and management you need, you can decide on the cloud service model. There are three types of cloud service models.
- Infrastructure as a Service (IaaS)
- Platform as a Service (PaaS)
- Software as a Service (SaaS)
On-premises Software:
On-premises Software are services that are deployed and managed on a hardware at an organizations building or own premises. These require you to buy a software license so you can install and use it on your own premises. Popular examples include Microsoft or Adobe products.
Cloud-based Services:
For cloud based services we use pay as you go model. So you don’t need to buy the whole software. You only need to pay for what you use. Based on your demand, flexibility and control you can choose between three models.
IaaS ( Infrastructure as a Service) model
It is also known as HaaS ( Hardware as a Service). Here the computing environment is managed over the internet. The user don’t have buy and manage physical servers. User have control over the data infrastructure. Scalable for complex projects.
Advantages:
- Easily scalable : Scaled up or down according to the needs.
- Lower costs
- Faster time to market
Disadvantages:
- You are in charge of the data. So anything lost you have to find a way to recover it.
- IaaS provides servers and APIs. You have to configure everything else.
PaaS (Platform as a Service)
PaaS is a scaled-down version of IaaS. It lets developers built custom applications online without having to deal with data servers, storage and management. SaaS applications are built on PaaS platforms. It is the ultimate solution for web applications.
Advantages:
- PaaS tools are very easy to use.
- Offers developers freedom to focus on application design without thinking about underlying operating system or infrastructure.
Disadvantages:
- You have control over the code of the app and not the infrastructure behind it.
- Limitations in customization.
- PaaS provider stores your data which is a security risk for app user’s data.
SaaS ( Software as a Service)
Most common service model. It doesn’t require download or installation and is easily available over the internet via subscription basis.
Advantages:
- Simple login services.
- Don’t have to manage or upgrade software.
Disadvantages:
- You have no control over the cloud based infrastructure.
- May be incompatible with other tools already in use at your business.
- Security may be questionable as provider manages and you don’t know whether data is exposed.
Examples of IaaS, PaaS, SaaS:
Key Points to remember in cloud service models:
| IaaS | PaaS | SaaS | |
| Provider manages | Infrastructure( network, virtualization, hardware ) | Infrastructure and Platform | Infrastructure, platform and software |
| You manage | Platform( OS, middleware, runtime ) and software( data and apps ) | Software | You manage nothing. Just use the software |