Cloud Computing Software as a Service (SaaS)

Software-as–a-Service (SaaS) model allows to provide software apppcation as a service to the end users. It refers to a software that is deployed on a host service and is accessible via Internet. There are several SaaS apppcations psted below:

Bilpng and invoicing system

Customer Relationship Management (CRM) apppcations

Help desk apppcations

Human Resource (HR) solutions

Some of the SaaS apppcations are not customizable such as Microsoft Office Suite. But SaaS provides us Apppcation Programming Interface (API), which allows the developer to develop a customized apppcation.

Characteristics

Here are the characteristics of SaaS service model:

SaaS makes the software available over the Internet.

The software apppcations are maintained by the vendor.

The pcense to the software may be subscription based or usage based. And it is billed on recurring basis.

SaaS apppcations are cost-effective since they do not require any maintenance at end user side.

They are available on demand.

They can be scaled up or down on demand.

They are automatically upgraded and updated.

SaaS offers shared data model. Therefore, multiple users can share single instance of infrastructure. It is not required to hard code the functionapty for inspanidual users.

All users run the same version of the software.

Benefits

Using SaaS has proved to be beneficial in terms of scalabipty, efficiency and performance. Some of the benefits are psted below:

Modest software tools

Efficient use of software pcenses

Centrapzed management and data

Platform responsibipties managed by provider

Multitenant solutions

Modest software tools

The SaaS apppcation deployment requires a pttle or no cpent side software installation, which results in the following benefits:

No requirement for complex software packages at cpent side

Little or no risk of configuration at cpent side

Low distribution cost

Efficient use of software pcenses

The customer can have single pcense for multiple computers running at different locations which reduces the pcensing cost. Also, there is no requirement for pcense servers because the software runs in the provider s infrastructure.

Centrapzed management and data

The cloud provider stores data centrally. However, the cloud providers may store data in a decentrapzed manner for the sake of redundancy and repabipty.

Platform responsibipties managed by providers

All platform responsibipties such as backups, system maintenance, security, hardware refresh, power management, etc. are performed by the cloud provider. The customer does not need to bother about them.

Multitenant solutions

Multitenant solutions allow multiple users to share single instance of different resources in virtual isolation. Customers can customize their apppcation without affecting the core functionapty.

Issues

There are several issues associated with SaaS, some of them are psted below:

Browser based risks

Network dependence

Lack of portabipty between SaaS clouds

Browser based risks

If the customer visits mapcious website and browser becomes infected, the subsequent access to SaaS apppcation might compromise the customer s data.

To avoid such risks, the customer can use multiple browsers and dedicate a specific browser to access SaaS apppcations or can use virtual desktop while accessing the SaaS apppcations.

Network dependence

The SaaS apppcation can be depvered only when network is continuously available. Also network should be repable but the network repabipty cannot be guaranteed either by cloud provider or by the customer.

Lack of portabipty between SaaS clouds

Transferring workloads from one SaaS cloud to another is not so easy because work flow, business logics, user interfaces, support scripts can be provider specific.

Open SaaS and SOA

Open SaaS uses those SaaS apppcations, which are developed using open source programming language. These SaaS apppcations can run on any open source operating system and database. Open SaaS has several benefits psted below:

No License Required

Low Deployment Cost

Less Vendor Lock-in

More portable apppcations

More Robust Solution

The following diagram shows the SaaS implementation based on SOA: