Cloud computing lets the client(either a user or program)request computing capabilities as needed,across network boundaries or any time.The cloud architecture has three layers,each of which can be called as a service.The software as service layer consists of software components and applications hosted by third-party service providers.The platform as service layer provides a collaborative development platform to assist with design,implementation,and testing by geographically distributed team members.Infrastructure as a service provides virtual computing resources(storage,processing power,network connectivity)on the cloud.