What is cloud computing?
Cloud computing is a category of computing solutions, technologies and / or service lets users access computing resources as needed, whether resources are physical or virtual, dedicated or shared, however access (via direct connection, LAN, WAN or Internet connection). Often there is a self-service interface to the cloud, customers can obtain the resources needed. Clouds can be seen as a way to build and use server virtualization capabilities IT services.
Private (internal) cloud can regenerate public cloud delivery model, we can represent the organization and customers behind a firewall implementation. There are still self-management interface, IT infrastructure resources while collecting is inside.
In general, the public (external) cloud is a company located outside the firewall environment. It can make use of third-party suppliers to provide services. It can also be referred to as a shared multi-tenant, virtualized infrastructure, you can use the self-service portal management.
In hybrid cloud environments, the use of external service extension or supplement an internal cloud.