Public clouds (or external clouds)

Private clouds (or internal clouds) emulate cloud computing on private networks

Hybrid clouds merge multiple internal and/or external clouds

Infrastructure as a Service (IaaS)

• Infrastructure as a Service (IaaS)

• provides computing environments/infrastructure i.e., hardware, software
• the provisioned infrastructure can dynamically scale up and down depending on the actual needs
• Amazon EC2 and S3

• Platform as a Service (PaaS)

• high-level integrated environment to build and deploy applications
• restrictions on the type of applications
• but scalable platform
• Google’s App Engine for deploying Web applications

• Software as a Service (SaaS)

• delivers software to consumers through the Internet
• Salesforce: online CRM (Customer Relationship Management) Services ; Live Mesh from Microsoft: files and folders synchronization