Skip to main content

Cloud Computing Service Models


Cloud computing providers offer their services according to several fundamental models: infrastructure as a service (IaaS), platform as a service (PaaS), and software as a service (SaaS) where IaaS is the most basic and each higher model abstracts from the details of the lower models. Other key components in XaaS are described in a comprehensive taxonomy model published in 2009, such as Strategy-as-a-Service, Collaboration-as-a-Service, Business Process-as-a-Service, Database-as-a-Service, etc. In 2012, network as a service (NaaS) and communication as a service (CaaS) were officially included by ITU (International Telecommunication Union) as part of the basic cloud computing models, recognized service categories of a telecommunication-centric cloud ecosystem.
Cloud computing layers.png

Infrastructure as a service (IaaS)

In the most basic cloud-service model, providers of IaaS offer computers - physical or (more often) virtual machines - and other resources. (A hypervisor, such as Xen or KVM, runs the virtual machines as guests. Pools of hypervisors within the cloud operational support-system can support large numbers of virtual machines and the ability to scale services up and down according to customers' varying requirements.) IaaS clouds often offer additional resources such as a virtual-machine disk image library, raw (block) and file-based storage, firewalls, load balancers, IP addresses, virtual local area networks (VLANs), and software bundles. IaaS-cloud providers supply these resources on-demand from their large pools installed in data centers. For wide-area connectivity, customers can use either the Internet or carrier clouds (dedicated virtual private networks).
To deploy their applications, cloud users install operating-system images and their application software on the cloud infrastructure. In this model, the cloud user patches and maintains the operating systems and the application software. Cloud providers typically bill IaaS services on a utility computing basis[citation needed]: cost reflects the amount of resources allocated and consumed.
Cloud communications and cloud telephony, rather than replacing local computing infrastructure, replace local telecommunications infrastructure with Voice over IP and other off-site Internet services.

Platform as a service (PaaS)

In the PaaS model, cloud providers deliver a computing platform typically including operating system, programming language execution environment, database, and web server. Application developers can develop and run their software solutions on a cloud platform without the cost and complexity of buying and managing the underlying hardware and software layers. With some PaaS offers, the underlying computer and storage resources scale automatically to match application demand such that cloud user does not have to allocate resources manually.

Software as a service (SaaS)

In the SaaS model, cloud providers install and operate application software in the cloud and cloud users access the software from cloud clients. Cloud users do not manage the cloud infrastructure and platform where the application runs. This eliminates the need to install and run the application on the cloud user's own computers, which simplifies maintenance and support. Cloud applications are different from other applications in their scalability—which can be achieved by cloning tasks onto multiple virtual machines at run-time to meet changing work demand.[53]Load balancers distribute the work over the set of virtual machines. This process is transparent to the cloud user, who sees only a single access point. To accommodate a large number of cloud users, cloud applications can be multitenant, that is, any machine serves more than one cloud user organization. It is common to refer to special types of cloud based application software with a similar naming convention: desktop as a service, business process as a service, test environment as a service, communication as a service.
The pricing model for SaaS applications is typically a monthly or yearly flat fee per user, so price is scalable and adjustable if users are added or removed at any point.
Examples of SaaS include: Google Apps, Microsoft Office 365, Onlive, GT Nexus, Marketo, Casengo and TradeCard.

Network as a service (NaaS)

A category of cloud services where the capability provided to the cloud service user is to use network/transport connectivity services and/or inter-cloud network connectivity services. NaaS involves the optimization of resource allocations by considering network and computing resources as a unified whole.
Traditional NaaS services include flexible and extended VPN, and bandwidth on demand. NaaS concept materialization also includes the provision of a virtual network service by the owners of the network infrastructure to a third party (VNP – VNO).

Comments

Post a Comment

Popular posts from this blog

Email Notifications not working in Sharepoint Tasks List

I had understood all the mechanics of the notification process I looked for something wrong in my environment. Everything was fine so I started my research around Tasks list security. Here are the scenarios I tested and also my remarks: 1. I left the permissions inheritance unbroken. The list didn’t have any permission for the AssignedTo user. It was clear that trimming mechanism came into play and immediate alerts job doesn’t send any email. So ensure you assign the needed level of permissions to the AssignedTo user of the task item because it is the one that will receive the email notifications. 2. I broke the inheritance and added permissions only to the AssignedTo user. Surprise: that time was working! The task creation email notification was sent. 3. I moved the code that creates the permissions for the user above the one that creates permissions for the group. Surprise again! It was working. 4. I thought it might have something to do with the Update method call so I jus
Post a Comment
Read more

SharePoint 2010 Features

Following are the features coming with SharePoint 2010 1. Inline editing for list items : no need to hit the datasheet view 2. BDC will be a two way road : sp2010 may support inserting data from BDC 3. No IE 6.0 Support : SharePoint 2010 will be “targeting standards based browsers (XHTML 1.0 compliant) including Internet Explorer 7, Internet Explorer 8 and Firefox 3.x. running on Windows Operating Systems. 4. With same architechture as of MOSS 2007, the stress will be on intergarting the advanced UI features, watchout for office like ribbon control, ajaxed controls etc 5. Content Management Interoperability Services : This will allow SharePoint to communicate with other CMS Refer @ http://www.ashwinbhagwat.com/my_blogs.html
Post a Comment
Read more

Expecting IT Refund from Income Tax Department, India

I had filed IT Return for AY2017-18 on 01st Jun 2017. I did e-Verify on same day. It took 84 days to get the refund after eVeryfying. Refunds are being sent in following two modes: RTGS / NECS:  To enable credit of refund directly to the bank account, Taxpayer.s Bank A/c (at least 10 digits), MICR code of bank branch and correct communication address is mandatory. Paper Cheque:  Bank Account No, Correct address is mandatory.   To check the refund status please visit: https://tin.tin.nsdl.com/oltas/refundstatuslogin.html Please enter you PAN number and select appropriate Assessment Year (AY). Enter correct captcha text. Then click on Submit button which will fetch the correct status for your return pertaining selected AY. After the status moved to ITR Processed on 21st August. It took 2 working days to get the amount credited in my bank account. If you have added the bank account details then the Mode of Payment will be "NECS". The status was "The As
Post a Comment
Read more