Public cloud services are offered over a network that is open to public use. These services may be offered using either paid or free usage models. While there can be little architectural difference between public cloud and private cloud systems, security considerations can be exponentially more difficult to address since communications can occur over non-trusted networks.
Many public cloud providers own and operate their own infrastructure at a data center and do not offer direct connectivity. Access is generally granted over the Internet. Public cloud services offer great scalability, and allow you to respond to changes in your business.
Private cloud services are operated for a single organization. They can be managed by the company itself or by a third-party company, and hosting can be done either on-site or off-site. Building your own private cloud can be costly, both in terms of time and money. Additionally, if you choose to host your private cloud on-site, they can require a lot of space.
If building your own private cloud, security issues should be addressed at each step in the initial setup process to prevent vulnerabilities that could potentially be exploited. Done correctly, a private cloud can improve your business and offers enhanced security and customization.
Hybrid cloud services are a combination of multiple clouds, either public or private, that are separate systems which have been bound together. The term can also be used to describe the ability to connect managed and/or dedicated services using cloud resources. A hybrid cloud can extend the capacity or the capability of a cloud service by utilizing the strengths of different cloud types.
This type of service gives you the flexibility to integrate off-site cloud systems with your existing physical servers.