Cloud computing is an internet based new age computer technology. It is the next stage technology that uses the clouds to provide the services whenever and wherever the user need it.It provides a method to access several servers world wide.

Some of the essential characteristics of cloud computing include:

1. On-demand self-service: A user can independently provision computing capabilities such as network storage, server time etc. as per requirement. All of these can be done without any human interaction with each service provider.
2. Broad network access: Client platforms such as laptops, mobile phones, tablets, and workstations are used to access and promote capabilities that are available over the network through standard mechanisms.
3. Resource pooling: According to consumer demand, the service provider’s computing resources are pooled to cater to multiple consumers using a multi-tenant model. Resources, both physical and virtual, are dynamically assigned and reassigned as per requirement and demand.
4. Rapid elasticity: It is a term used for scalable provisioning. It is the ability to provide scalable services rapidly for inward and outward in proportion to the consumer’s demand.
5. Measured service: This is a service where cloud service providers monitor or measure the provision of services for various reasons which include billing, proper use of resources, or entire predictive planning.

Communications as a Service (CaaS) is one of the categories of cloud computing services is a solution available on lease from a single vendor for enterprise communication. It includes communication services such as VOIP (voice-over internet protocol), instant messaging services, video-conferencing applications etc.

It is also a layer in cloud architecture. This model is built on the infrastructure model and provide resources like computers, storage and network. It is responsible to provide complete virtualization of the infrastructure layer, make it look like a single server and invisible for outside world.

The main benefits of cloud computing are:

• Data backup and storage of data.
• Powerful server capabilities.
• Incremented productivity.
• Very cost effective and time saving.
• Software as Service known as SaaS.

Security plays a vital role with any application and service used by the user. All organizations are always concerned about the security provided with the cloud. There are levels of security which are provided along with cloud environment:

• Identity management: This level authorizes the hardware component or application service to be used by authorized users.
• Access Control: This level allows permission to users so that organizations have control and access over other users who are a part of the cloud environment.
• Authorization and Authentication: This gives a provision to allow people who are authorized and authenticated to change and access the application and data.

The parts of the cloud ecosystem that determine how you view the cloud architecture are:

• Cloud consumers
• Direct customers
• Cloud service providers

• Containerized datacenter
• Low density datacenter

Following are the mostly used large cloud providers and databases:

• Google bigtable
• Amazon simpleDB
• Cloud based SQL

Hybrid cloud is a cloud computing environment which is basically a composition of two or more clouds. It can be a combination of private and community, or private and public and so on. It is bound together and offers the benefit of multiple deployment models. Hybrid cloud also has the ability to connect collocation, dedicated and/or managed services with cloud resources.