There are many components of your IT infrastructure that can be deployed to the cloud. With grid computing, driving data center consolidation and resource sharing, the need to further cut the cost of operating data centers filled with disparate systems led to an evolution known as cloud computing. The National Institute of Standards and Technology (NIST) define cloud computing as follows:

The basic premise of cloud computing is that users can get access to any IT resource, including storage, CPU resources, memory, and software, over the Internet whenever they want. Users can pay for their actual use of the resource, rather than incurring capital and operational expenditures in order to own and operate the IT infrastructure. This computing scheme closely mimics the way households pay for utilities such as electricity and gas on metered usage.

The NIST cloud computing model is composed of five unique characteristics, three service models, and four deployment models. The five characteristics associated with this model mainly enable easier availability of metered, scalable, elastic computing resources that can be provisioned through self-service and can be accessed from any thin or thick client over the network.

The most well-known option is to run your applications in the cloud using Software-as-a-Service (SaaS). It is also possible to run your database systems in the cloud using Database-as-a-Service (DaaS). It is even possible to run your entire IT software and hardware infrastructure in the cloud using Platform-as-a-Service (PaaS). It is also possible to deploy your integration architecture into the cloud, Integration-as-a-Service (INaaS).

INaaS is defined and implemented using a variety of technologies. It all depends upon the IT vendor you are referring to. IT vendors are going to define and implement INaaS that most closely matches their current product offerings. Most INaaS offerings make use of web services, well-defined interfaces, and are loosely coupled. Some vendors offerings are nothing more than placing their current integration products, with some minor changes, in a PaaS environment and branding the solution as INaaS.

For SaaS providers, an INaaS solution is a necessity. As SaaS gains greater acceptance among companies of all size, there is a need to exchange data from in-house hosted applications and databases to the newer SaaS solutions and hosting facilities. However, there is also an increasing need for data integration solutions aimed at integrating a variety of SaaS solutions to support a company's internal processes and external interactions. This is because SaaS is not only being used within enterprises to facilitate various internal functions, it also enables companies to transact business with other companies over the Internet.

Saleforce.com is the leading independent SaaS provider. Looking at what Salesforce.com is doing in the INaaS space is a logical place to start when discussing INaaS and SaaS. Salesforce.com's approach to INaaS is to offer rich web services APIs and a catalog of pre-integrated applications. The developer API-focused approach makes sense given Salesforce.com's rich heritage of developing easy to use and extensible applications which are accessible over the Internet.

Workday is another pure-play SaaS provider to enterprise customers. The Workday cloud-based approach to integration is more extensive than what is offered by Salesforce.com as it includes these three core components:

Traditional integration IT vendors are also starting to offer INaaS. Infomatica has been the most aggressive integration vendor when it comes to offering INaaS. Informatica has offered INaaS for over five years and continues to add capabilities, has a number of high profile references, and also continues to add out of the box cloud integration with major COTS and SaaS providers. Informatica Marketplace contains pre-packaged Informatica Cloud end-points and plugins. One such Marketplace solution, is integration with Oracle E-Business Suite using Informatica integration. The Informatica E-Business Suite INaaS offering includes automatic loading and extraction of data between the Salesforce CRM and on-premise systems, cloud-to-cloud, flat files, and the relational database. The entire Informatica Cloud integration solution runs in an Informatica-managed facility (PaaS). When running in a PaaS environment, Informatica offers an option to keep an exact copy of your cloud-based data on-premise for archival, compliance, and enterprise reporting requirements.

A new technology area like cloud computing always attracts new IT vendors that provide solutions specific to the new technology area. This is the case in cloud computing and new IT vendors that offer products specific to INaaS. Hubspan and Cordys are two such companies. Hubspan offers a multitenant integration platform that can handle all major enterprise applications, transports, and data formats, as well as core business processes such as procurement, logistics, payments, and human capital management. The Hubspan solution is offered in a SaaS model. Cordys offers a Business Operations Platform (BOP) suite as a PaaS enablement play for enterprises. Its vision is to become an enterprise application integration replacement by providing 'Tibco-like integration' in the cloud. Cordys BOP suite includes Business Application Monitoring (BAM), BPM, master data management, and integration tools.