Cloud Computing Models and Types of Cloud

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 Cloud Computing Models Or LAYERS

Cloud computing services are divided into three classes, according to the abstraction level of the capability provided and the service model of providers, namely:

  1. Infrastructure as a Service (IaaS)
  2. Platform as a Service (PaaS)
  3. Software as a Service. (SaaS)

 Software as a Service (SaaS)

 In this model, a complete application is offered to the customer, as a service on demand. A single instance of the service runs on the cloud & multiple end users are serviced. On the customers‟ side, there is no need for upfront investment in servers or software licenses, while for the provider, the costs are lowered, since only a single application needs to be hosted & maintained. 

Ex: Today SaaS is offered by companies such as Google, Salesforce, Microsoft, Zoho, etc.

More from SaaS :

  • Applications are supplied by the service provider.
  • The user does not manage or control the underlying cloud infrastructure or individual application capabilities.
  • Services offered include:
            (i) Enterprise services such as: workflow management, group-ware and collaborative, supply chain, communications, digital signature, customer relationship management (CRM), desktop software, financial management, geo-spatial, and search.
            (ii) Web 2.0 applications such as: metadata management, social networking, blogs, wiki services, and portal services.
  • Not suitable for real-time applications or those where data is not allowed to be hosted externally.
  • Examples: Gmail, Google search engine.

 Platform as a Service (Paas)

 Here, a layer of software, or development environment is encapsulated & offered as a service, upon which other higher levels of service can be built. The customer has the freedom to build his own applications, which run on the provider‟s infrastructure. To meet manageability and scalability requirements of the applications, PaaS providers offer a predefined combination of OS and application servers.

Ex: LAMP platform (Linux, Apache, MySql and PHP), restricted J2EE, Ruby etc. Google‟s App Engine, Force.com.

More form PaaS:

  • Allows a cloud user to deploy consumer-created or acquired applications using programming languages and tools supported by the service provider.
  • The user:
    • has control over the deployed applications and, possibly, application hosting environment configurations
    • does not manage or control the underlying cloud infrastructure including network, servers, operating systems, or storage
  • Not particularly useful when:
    • the application must be portable
    • proprietary programming languages are used
    • the hardware and software must be customized to improve the performance of the application.

 Infrastructure as a Service (Iaas)

 IaaS provides basic storage and computing capabilities as standardized services over the network. Servers, storage systems, networking equipment, datacentre space etc. are pooled and made available to handle workloads. The customer would typically deploy his own software on the infrastructure. 

Ex:Some common examples are Amazon, GoGrid, 3 Tera, etc.

More from IaaS:

  • The user is able to deploy and run arbitrary software, which can include operating systems and applications.
  • The user does not manage or control the underlying cloud infrastructure but has control over operating systems, storage, deployed applications, and possibly limited control of some networking components, e.g., host firewalls.
  • Services offered by this delivery model include: server hosting, web servers, storage, computing hardware, operating systems, virtual instances, load balancing, Internet access, and bandwidth provisioning.

Types of clouds or Cloud deploy models

The Cloud can be classified as 4 types
  1. Private Cloud
  2. Public Cloud
  3. Community Cloud
  4. Hybrid Cloud

Public Cloud 

The infrastructure is made available to the general public or a large industry group and is owned by the organization selling cloud services.

public cloud infrastructure is

  •  provisioned for open use by public
  •  Owned, managed and operated by a business, government or university
  •  Mostly in the premises of a cloud provider 

Private Cloud 

In this cloud infrastructure operated solely for an organization.

Private cloud the cloud infrastructure is

  • provisioned for exclusive use by a single organization with multiple consumers,
  • for example individual business units  owned, managed, and operated by the organization 

Community Cloud 

 In this cloud the infrastructure is shared by several organizations and supports a specific community that has shared.

community cloud for use by a community

  • Owned by specific community of consumers from organizations that have shared concerns , missions of security etc.
  •  owned, managed, and operated by the organization in the community 

Hybrid Cloud 

 composition of two or more clouds (public, private, or community) bound by standardized technology that enables data and application portability. 

Hybrid cloud infrastructure is

  •  Consists of two or more distinct cloud infrastructures
  •   Can be private, public, or community based
  •  Can be proprietary or standardized 
  • More complex integrated systems
  •  Subject to implications and constraints 

More Content from Cloud Computing: see below Table Content

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