Cloud based IT resources can be consumed for various reasons in myriad ways. That the IT industry has really rallied around three standard cloud computing services models:
Infrastructure as a service (IaaS): This is really the most basic cloud service model, aligning the on demand resources of the cloud with tactical IT needs. In this way, IaaS is similar to managed services offerings of the Internet era (i.e., hosting services, storage service providers (SSPs), etc.). The primary difference is that cloud resources are virtual rather than physical and can be consumed on an as needed basis. In other words, enterprise consumers pay for virtual machines (VMs), storage capacity, and network bandwidth for a variable amount of time rather than servers, storage arrays, and switches and routers on a contractual basis. Typically, enterprises have no control over the underlying cloud technology. As described above, IaaS can be utilized as a temporary resource or used for years at a time. IaaS prices are based upon two factors: IaaS resource consumption and the duration of use.
Platform as a service (PaaS): Simply stated, PaaS provides the capability to build or deploy applications on top of IaaS. Typically, a cloud computing provider offers multiple application components that align with specific development models and programming tools. For the most part, PaaS offerings are built upon either a Microsoft based stack (i.e., Windows, .NET, IIS, SQL Server, etc.) or an open source based stack (i.e., the “LAMP” stack containing Linux, Apache, MySQL, and PHP).
Software as a service (SaaS): In this model, an entire business or set of IT applications runs in the cloud. Enterprise consumers outsource the entire underlying technology infrastructure to a SaaS provider and thus have no responsibility or management oversight for SaaS--‐based IT components. Users typically access these applications over the Internet through a thin client interface such as a Web browser. SaaS examples include Gmail from Google, Microsoft “live” offerings, and salesforce.com.
There is no hierarchy in these service offerings; rather, CIOs can choose any or all cloud service offerings that fit their needs.
Infrastructure as a service (IaaS): This is really the most basic cloud service model, aligning the on demand resources of the cloud with tactical IT needs. In this way, IaaS is similar to managed services offerings of the Internet era (i.e., hosting services, storage service providers (SSPs), etc.). The primary difference is that cloud resources are virtual rather than physical and can be consumed on an as needed basis. In other words, enterprise consumers pay for virtual machines (VMs), storage capacity, and network bandwidth for a variable amount of time rather than servers, storage arrays, and switches and routers on a contractual basis. Typically, enterprises have no control over the underlying cloud technology. As described above, IaaS can be utilized as a temporary resource or used for years at a time. IaaS prices are based upon two factors: IaaS resource consumption and the duration of use.
Platform as a service (PaaS): Simply stated, PaaS provides the capability to build or deploy applications on top of IaaS. Typically, a cloud computing provider offers multiple application components that align with specific development models and programming tools. For the most part, PaaS offerings are built upon either a Microsoft based stack (i.e., Windows, .NET, IIS, SQL Server, etc.) or an open source based stack (i.e., the “LAMP” stack containing Linux, Apache, MySQL, and PHP).
Software as a service (SaaS): In this model, an entire business or set of IT applications runs in the cloud. Enterprise consumers outsource the entire underlying technology infrastructure to a SaaS provider and thus have no responsibility or management oversight for SaaS--‐based IT components. Users typically access these applications over the Internet through a thin client interface such as a Web browser. SaaS examples include Gmail from Google, Microsoft “live” offerings, and salesforce.com.
There is no hierarchy in these service offerings; rather, CIOs can choose any or all cloud service offerings that fit their needs.
