I am a strong believer of Cloud Computing. It is the trend of the IT industry, no matter hardware vendors or software vendors will eventually step in this filed or die. Actually, it is happening now. In the future, Cloud Computing will be just like the water, electricity and cable those daily things that we pay for monthly to get the services. And we can also easily move to another Cloud service provider that can provide better price and services. Currently, Saas, PaaS and Iaas are the three main categories of Cloud Computing Service Model in the market.
Software as a Service (SaaS) is a software distribution model in which applications are hosted by a vendor or service provider and made available to customers over a network, typically the Internet.
SaaS is becoming an increasingly prevalent delivery model as underlying technologies that support Web services and service-oriented architecture (SOA) mature and new developmental approaches, such as Ajax, become popular. Meanwhile, broadband service has become increasingly available to support user access from more areas around the world.
SaaS is closely related to the ASP (application service provider) and on demand computing software delivery models. IDC identifies two slightly different delivery models for SaaS. The hosted application management (hosted AM) model is similar to ASP: a provider hosts commercially available software for customers and delivers it over the Web. In the software on demand model, the provider gives customers network-based access to a single copy of an application created specifically for SaaS distribution.
Platform as a Service (PaaS) is a way to rent hardware, operating systems, storage and network capacity over the Internet. The service delivery model allows the customer to rent virtualized servers and associated services for running existing applications or developing and testing new ones.
Platform as a Service (PaaS) is an outgrowth of Software as a Service (SaaS), a software distribution model in which hosted software applications are made available to customers over the Internet. PaaS has several advantages for developers. With PaaS, operating system features can be changed and upgraded frequently. Geographically distributed development teams can work together on software development projects. Services can be obtained from diverse sources that cross international boundaries. Initial and ongoing costs can be reduced by the use of infrastructure services from a single vendor rather than maintaining multiple hardware facilities that often perform duplicate functions or suffer from incompatibility problems. Overall expenses can also be minimized by unification of programming development efforts.
On the downside, PaaS involves some risk of “lock-in” if offerings require proprietary service interfaces or development languages. Another potential pitfall is that the flexibility of offerings may not meet the needs of some users whose requirements rapidly evolve.
Infrastructure as a Service (IaaS) is a provision model in which an organization outsources the equipment used to support operations, including storage, hardware, servers and networking components. The service provider owns the equipment and is responsible for housing, running and maintaining it. The client typically pays on a per-use basis. nfrastructure as a Service is sometimes referred to as Hardware as a Service (HaaS)
Some segments within the three major Cloud services.
Identity as a Service (IDaaS) is an authentication infrastructure that is built, hosted and managed by a third-party service provider. IDaaS can be thought of as single sign-on (SSO) for the cloud.
An IDaaS for the enterprise is typically purchased as a subscription-based managed service. A cloud service provider may also host applications for a fee and provide subscribers with role-based access to specific applications or even entire virtualized desktops through a secure portal.
Storage as a Service (SaaS) is a business model in which a large company rents space in their storage infrastructure to a smaller company or individual.
In the enterprise, SaaS vendors are targeting secondary storage applications by promoting SaaS as a convenient way to manage backups. The key advantage to SaaS in the enterprise is in cost savings — in personnel, in hardware and in physical storage space. For instance, instead of maintaining a large tape library and arranging to vault (store) tapes offsite, a network administrator that used SaaS for backups could specify what data on the network should be backed up and how often it should be backed up. His company would sign a service level agreement (SLA) whereby the SaaS provider agreed to rent storage space on a cost-per-gigabyte-stored and cost-per-data-transfer basis and the company’s data would be automatically transferred at the specified time over the storage provider’s proprietary wide area network (WAN) or the Internet. If the company’s data ever became corrupt or got lost, the network administrator could contact the SaaS provider and request a copy of the data.
Storage as a Service is generally seen as a good alternative for a small or mid-sized business that lacks the capital budget and/or technical personnel to implement and maintain their own storage infrastructure. SaaS is also being promoted as a way for all businesses to mitigate risks in disaster recovery, provide long-term retention for records and enhance both business continuity and availability.
Communications as a Service (CaaS) is an outsourced enterprise communications solution that can be leased from a single vendor. Such communications can include voice over IP (VoIP or Internet telephony), instant messaging (IM), collaboration and videoconference applications using fixed and mobile devices. CaaS has evolved along the same lines as Software as a Service (SaaS).
The CaaS vendor is responsible for all hardware and software management and offers guaranteed Quality of Service (QoS). CaaS allows businesses to selectively deploy communications devices and modes on a pay-as-you-go, as-needed basis. This approach eliminates the large capital investment and ongoing overhead for a system whose capacity may often exceed or fall short of current demand.
CaaS offers flexibility and expandability that small and medium-sized business might not otherwise afford, allowing for the addition of devices, modes or coverage on demand. The network capacity and feature set can be changed from day to day if necessary so that functionality keeps pace with demand and resources are not wasted. There is no risk of the system becoming obsolete and requiring periodic major upgrades or replacement.
Security-as-a-service (SaaS) is an outsourcing model for security management. Typically, Security as a Service involves applications such as anti-virus software delivered over the Internet but the term can also refer to security management provided in-house by an external organization. Security as a Service product vendors include Cisco, McAfee, Panda Software, Symantec, Trend Micro and VeriSign.