Introduction
Cloud computing has rapidly emerged as a method for service delivery over TCP/IP networks such as the Internet. It disrupts the traditional IT computing environment by providing organizations with an option to outsource the hosting and operations of their mission-critical business applications. Subscribers typically access cloud services using desktop-hosted web browsers as clients or, in the case of cloud telephony, VoIP hardphones or softphones. In addition to financial benefits such as minimal capital and operational expenditure (CAPEX and OPEX) costs, the cloud model provides several technical benefits including flexible hardware and software allocation, elasticity. and performance isolation.