What is cloud computing?

“Cloud computing” refers to the use of technology resources that are available to you on an on-demand basis via the Internet. This is in contrast to conventional on-premise IT, where your company runs its applications exclusively on its own internal infrastructure—including servers, storage, networks, firewalls, load balancers and other hardware.

What are cloud computing service and deployment models?

Cloud computing service models can be described as follows:

  • Infrastructure-As-A-Service (IaaS) – Provides computing hardware such as servers, network equipment, and data storage on a scalable basis in the cloud. A common use of IaaS is cloud-based backup and recovery.
  • Platform-As-A-Service (PaaS) – Provides an application development environment that allows users to collaborate, develop, test, deploy, host and maintain applications in the cloud. A common use of PaaS is cloud-based environments for the development of enterprise-level software.
  • Applications-As-A-Service (AaaS)/Software-As-A-Service (SaaS) -Provides access to software. Users can log-on from anywhere and have full access to their specific software in the cloud. A common use of SaaS is cloud-based e-mail.
  • Depending upon the users’ needs, and other considerations, cloud computing services are typically deployed using one of the following four models as defined by NIST (see http://csrc.nist.gov/groups/SNS/cloud-computing/index.html) :
  • Private cloud. A private cloud is operated for a specific organization. It may be managed by the organization or a third party and may exist on premises or off premises.
  • Public cloud. A public cloud is made available to the general public or a large industry group and is owned by an organization selling cloud services.
  • Community cloud. A community cloud is an infrastructure shared by several organizations and supports a specific community that has shared concerns (e.g., mission, security requirements, policy, and compliance considerations). It may be managed by the organizations or a third party and may exist on premises or off premises.
  • Hybrid cloud. A hybrid cloud is a composition of two or more clouds (private, community, or public) that remain unique entities but are bound together by standardized or proprietary technology that enables data and application portability.

What are the benefits/concerns of cloud computing?

There are a number of benefits and concerns associated with implementing cloud computing services. Cloud computing is evolving, therefore, some of the listed benefits and concerns may change.

Common benefits include:

  • Cost savings with “pay-as-you go” service plans.
  • Scalability of resource procurement in response to needed IT capacity.
  • Accessibility of services often from any networked machine.
  • Collaboration capabilities with access to shared applications and records.
  • Flexibility to procure resources on demand.
  • Capacity to outsource large computing needs and non-critical applications.

Common concerns include:

  • Stable Internet connection needed
  • Slow data transfer rate(s) for large file(s)