This document defines and describes the key concepts of cloud computing including its five characteristics, four deployment models, and three service models. The five characteristics that define cloud computing are on-demand self-service, broad network access, resource pooling, rapid elasticity, and measured service. The four deployment models are public cloud, private cloud, community cloud, and hybrid cloud. The three service models are Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS).

1. 1. The Principles of Cloud
Computing

2. 1.1 The Concept of Cloud
Computing

3. Overview of the Concept of Cloud
Computing

4. 1.1.1 Five Characteristics
• On-demand self-service
• Resource pooling (multi-tenancy)
• Rapid elasticity (flexibility, scalability)
• Measured service (pay-per-use)
• Broad network access ("any time, any place, any
device”)

5. Cloud Computing:
Some examples
• For everyone:
• Facebook, twitter (social media)
• Wiki’s
• Online games
• Hotmail (webmail)
• Dropbox
• For business:
• CRM
• Backup services
• ERP
• Financial
• Etc…

6. 1.1.2 Four Deployment models
Public, Private, Community and Hybrid Clouds

7. Private Cloud: just another name for a data
center?
• resides on a private network that runs on (part of) a
data center that is exclusively used by one
organization;
• owned, managed and run by either the organization
itself, a third party or a combination of the two;
• supports the organization’s business objectives in an
economic sound way;
• high security (compliance with legislation and
regulations).

8. Public Cloud
• Delivery of off-site services over the internet
• Sharing of resources; ‘multi-tenancy’ means a lower
level of security and privacy
• Aimed at a wide audience
• Compelling services like email and social media
• Enables social networking and collaboration

9. Community Cloud
• A type of shared private cloud
• Delivers services to a specific group of organizations and/or
individuals that share a common goal
• Sharing of data, platforms and applications
• Sharing of capital expenditure for otherwise (too) expensive
facilities
• 24/7 access and support
• Shared service and support contracts
• Economics of scale
Examples: regional or national educational or research institutes,
community centers, etc.

10. Hybrid Cloud
• A mix of the above models; combining several Private
and Public Cloud solutions from several providers into
one (virtual) IT infrastructure
• Choosing specific services for either Private or Public
Cloud suitability is balancing:
• security
• privacy
• compliance versus price

11. 1.1.3 Cloud Service Models
• Software as a Service (SaaS)
• The customer does not need to worry about the
development and management of applications.
• Platform as a Service (PaaS)
• Not owning a computer platform, but being able to use it
‘on demand’ can save costs in ownership, management and
maintenance.
• Infrastructure as a Service (IaaS)
• Rental of physical or virtual hardware like storage, servers
or internet connectivity.

12. SaaS
• Key characteristics:
• Software hosted offsite
• Software on demand
• Software package
• No modification of the software
• Plug-in software: external software used with internal
applications (Hybrid Cloud)
• Vendor with advanced technical knowledge
• User entangled with vendor
• Examples: CRM, ERP, Billing and invoicing, Web
Hosting, Etc.

13. PaaS
• Key characteristics:
• Mostly used for remote application development
• Remote application support
• Platform may have special features
• Low development costs
• Variants
• Environment for software development
• Hosting environment for applications
• Online storage

14. IaaS
• The background of IaaS can be found in the merger
between IT and Telecom infrastructure and services in the
past decade
• Key characteristics:
• Dynamic scaling
• Desktop virtualization
• Policy-based services
• Examples of IaaS are hosting services supporting e-
commerce, web hosting services that include broadband
connections and storage.