Cloud computing: Pay only for value, not technology

One vision of 21st century computing is that users will access Internet services over lightweight portable devices rather than through some descendent of the traditional desktop PC. Because users won’t have powerful machines, who will supply the computing power? The answer to this question lies with cloud computing.

Cloud computing is a recent trend in IT that moves computing and data away from desktop and portable PCs into large data centers. It refers to applications delivered as services over the Internet as well as to the actual cloud infrastructure. National institute of standards and technology defines cloud computing as, “Cloud computing is a model for enabling suitable, on demand network access to a shared pool of configurable computing resources that can be rapidly provisioned and released with minimal management effort or service provider interaction”. Cloud architecture typically involves multiple cloud components communicating with each other over application programming interfaces, usually services. Cloud computing allows consumers and businesses to use applications without installation and access their personal files at any computer with internet access.

The key driving forces behind cloud computing is the ubiquity of broadband and wireless networks, falling storage costs and progressive improvements in Internet computing software. Cloud-service clients will be able to add more capacity at peak demand, reduce costs, experiments with new services and remove unneeded capacity, whereas service providers will increase utilization via multiplexing and allow for larger investments in software and hardware.

Cloud model comprises of five essential characteristics, which are; On-demand self-service, broad network access, resource pooling, measured service and rapid elasticity. On-demand self service enable users to use cloud computing resources as needed without human interaction between the user and the provider. So this ease of use and elimination of human interaction provides efficiencies and cost savings to both users and cloud service providers. When cloud computing is to be efficient and effective replacement for in house data centers, high bandwidth communication links must be available to connect to the cloud services. High bandwidth network communication provides access to a large pool of IT resources. The amount of cloud resources by a consumer can be monitored and billed automatically for usage of that particular session. Resource usage can be monitored, controlled and reported by providing transparency for both the provider and consumer of the utilized service.

Currently, the main technical underpinnings of cloud computing infrastructures and services include virtualization, service-oriented software, grid computing technologies, management of large facilities and power efficiency. Consumer purchases such services in the form of a service model. These service models are: Software as a Service (SaaS), Platform as a Service (PaaS) and Infrastructure as a Service (IaaS). Then these value added services are sold to users.

We can distinguish two different architectural models for clouds: the first one is designed to scale out by providing additional computing instances on demand. Clouds can use these instances to supply services in the form of SaaS and PaaS. The second architectural model is designed to provide data and compute-intensive applications via scaling capacity. In most cases, clouds provide on-demand computing instances or capacities with a “pay-as-you-go” economic model. The cloud infrastructure can support any computing model compatible with loosely coupled CPU clusters. Organizations can provide hardware for clouds internally (internal clouds), or a third party can provide it externally (hosted clouds). A cloud might be restricted to a single organization or group (private cloud), available to the general public over the Internet (public clouds), or shared by multiple groups or organizations (hybrid clouds).

Cloud computing is a disruptive technology with profound implications not only for Internet services but also for the IT sector as a whole. Its emergence promises to streamline the on-demand provisioning of software, hardware and data as a service, achieving economies of scale in IT solutions’ deployment and operation.

Still several outstanding issues exist, particularly related to service-level agreements (SLAs), security and privacy, and power efficiency. Other open issues include ownership, data transfer bottlenecks, performance unpredictability, reliability and software licensing issues. Finally, hosted applications’ business models must show a clear pathway to monetize cloud computing. Several companies have already built Internet consumer services such as search, social networking, Web email and online commerce that use cloud computing infrastructure. Above all, cloud computing is still unknown. Many of the key challenges need viable solutions to make this technology work in practice.