Abstract: The term cloud computing “Is a reset buzzword’s in IT world”. Cloud computing aimed at providing IT as a service to the cloud user on-demand basis with greater flexibility, availability, reliability and massive scalability with utility of computing mode. It is concept where a computer is created using internet with main purpose of utilizing share resources like computer, software and hardware etc. In general cloud computing is an internet based environment where you pay for resources that you use. The term cloud computing centralizing computation, it came in web backing in 1990’s. This paper represent review of cloud computing concept also different kinds of services provide over the cloud computing, cloud infrastructure, security. However, the vulnerabilities of the infrastructure involved in cloud – computing based on m- health system as well as problems and solutions in information security.

Keywords: Cloud Computing, Cloud services (IaaS, PaaS, SaaS), Complex network.