We are going to look into further details of the cloud service models.

First of all, look at this picture. At the bottom which is the infrastructure, the IaaS. And in here, virtual machines, server storage, network, is basically what is provides in the infrastructure. Above that is PaaS, where this is a platform as a service, and it includes database, web server and deployment tools. The next one on the top is SaaS and this is software as a Service. Here, CRM, email, games, virtual desktop and what is actually in the software application domain.

As mentioned in the last passage, the lower service model supports the upper one, so in other words, the software as a service needs platform as a service underneath it, and platform as a service needs infrastructure as a service underneath it. These together are a solid structure service model. The cloud clients will use web browsers, mobile apps and other client access applications to log in and receive these types of cloud services.

Infrastructure as a service

First, let’s take a look at infrastructure as a service. Infrastructure supports over the Internet and this is basically providing cloud computing and storage resources such as computing power, storage services, software packages and bundles, virtual local area networks, VLAN and also virtual machine features. This enables basically virtual machine administration, and this is providing control of computing resources through administrative access to virtual machines.

Server virtualization features are provided through this technology. Access to computing resources are enabled by administrative access to these virtual machines. A virtual machine administrative command example would save data on the cloud service, start web server, install a new application and these types of things are these types of administrative commands.

IaaS has these types of procedures. First,the software owner will create a virtual machine and upload it into the storage and the storage area network, the SAN.

Now, once it’s in the cloud servers, a virtual switch, a VSwitch can be used to pull the requested apps and OS and the virtual machine unit. From the VSwitch, the virtual machine is used by the users and their requests where the application and the OS, that operating package is delivered to the users so that they can use it. This is how infrastructure as a service works.

The benefits of IaaS

Well, flexible and efficient renting of computer server hardware. Here comes a question, what are the resources that you can rent? Well, virtual machine, storage, bandwidth, IP addresses, monitoring services, firewalls for security. In addition, the rent payment basis is focused on what type of resources am I requesting for. How much of time did I rent it? Are there any service packages that provide a combination? This will determine how much money I need to pay.

Therefore, the benefits of IaaS are portability and interoperability with legacy applications. In other words, it enables a method portability based on infrastructure resources that are used through Internet connections. In addition, it enables a method to maintain interoperability with legacy applications and workload between IaaS clouds.

Platform as a service

Platform as a service, provides development and deployment tools for application development. It provides runtime environment for apps. And as you can see in this figure, on the cloud server, the developers will put the IDE, the integrated development environment, such that components like data security, backup and recovery, application hosting and scalable infrastructure are inside the cloud servers so that users can access them whenever they need to.

The PaaS’s types

Application delivery-only environment, stand alone development environment, add-on development facilities, and open platform as a service. PaaS types include these type of further definitions. First, application delivery-only environment, this provides on-demand scaling and application security. Stand-alone development environment, this provides an independent platform for a specific function. The open platform as a service provides open-source software to run applications for PaaS providers. The add-on development facilities enables customization to the existing SaaS platforms.

The PaaS’s benefits

The PaaS’s benefits can be summarized into these four. Taking a closer look, which means lower administrative overhead. That means the user does not need to be involved in any administrative of the platform. Next, lower total cost of ownership. The user does not need to purchase any hardware, memory, or server, because the hardware, memory and the server, that’s basically what is already prepared in the cloud. All I need to do is log into it and received its services. The other two benefits? Scalable solutions, application resource demand based automatic resource scale control is provided through PaaS cloud services. More current system software, a cloud provider needs to maintain software upgrades and patch installations so the user does not need to. It’s all provided and everything should be upgraded and all the patches should be installed and ready for a user to come in and just use it.

Software as a service

This provides software applications as a service to the end user. Software that is deployed on a cloud service which is accessible through the Internet.

SaaS’s characteristics

The characteristics include on-demand availability. Cloud software is available anywhere that the cloud is reachable through the Internet. as maintenance, no user software upgrade or maintenance is needed. All of this should be supported by the cloud and the cloud administrators.

Flexible scale up or scale down which means that even though I start off with something small, if I need to grow on the overall structure of what is supported for a certain application, I can easily scale up, if I feel that I don’t need all of this, I can scale down, and that is provided because I’m using the cloud resources. In addition, centralized management and centralized data is one of the other features of SaaS.

In addition, SaaS enables a shared data model. Multiple users can share a single data model and a single database. Cost effectiveness, pay based on what you use. There is no risk in buying the wrong software. Basically you’re using, you’re renting, you are borrowing the software that’s already in the cloud. So, basically, if you buy the wrong software that’ in a package, you install it on your Pc, maybe you can feel that you did something wrong and may regard it, but actually, that’s not going to happen when you are using a SaaS cloud support. Multitenant programming solutions. Now, this is something cool, especially when you have multiple programmers trying to program something which later on, you need to mix and match and combined into one coordinated program to work on something like a big project together.

In some cases, if everybody bught their software separately, installed in on their PC and did their own program development, your programs may not combine well together because some of the versions and patches and upgrades may be different based upon the user. In this case, since everybody’s logging into the cloud and using the SaaS platform which is one unique software package that they bring to their computer as they access and program, there is no possible situation where is a version mismatch because everybody’s logging in and receiving the same version. And they do the development so basically it should combine together if you programmed everything correctly.

In SaaS, the open SaaS application looks like this. On the cloud servers, the components such as SaaS directory web service, SaaS messaging web service, SaaS collaboration web services and SaaS content web services are all installed.

In order for a user to get access to these SaaS features and functions, the user will have to use the client user interface, the client UI. And that will trigger operation through the SaaS orchestration unit which will enable the users to access these SaaS services.