d to all aspects; however, it has already gained a substantial momentum for service-delivery technologies toward a global service market place serving the large and small-medium enterprise market as well as the Telecom consumer mar- ket. This section shall provide a short view on selected topics of the still emerging cloud computing technologies. 4.3.1 Evolving of New Service Delivery Technology for the XaaS Trend Currently, the most known form of cloud computing is the on-demand support of the usage of IT and network infrastructure (such as processing power, bandwidth, and storage facilities) called Infrastructure as a Service (IaaS). Examples are AT&T's Synaptic Hosting or Amazon EC. The other popular type is the Software as a Service (SaaS) model. Hereby, a service provider offers applications on an "on- demand" basis (like for rental) over the IP network in real time, representing the offer of these applications from the cloud. This model is typically associated with the on-demand delivery of software for small-medium business with limited IT resources and includes originally applications like ERP, CRM, sales, backup, secu- rity, and messaging tools. SaaS can here be understood as evolution from the Service Delivery Platforms application service provider (ASP) delivery concept, offering a similar service deliv- ery business model. This model has been redusted, and mixed up with the Web mash-up emergence. It is all about providing any piece of software into a service for exposure to the consumption using mash-up technologies. As smashups live on the Web, the interaction with the cloud service delivery concept is a natural fit. The third prime type is the Platform as a Service (PaaS) concept. A PaaS is a collection of software development and testing tools in order to allow the creation of new applications using the providers' APIs. Currently, existing PaaS offering nonstan- dardized APIs resulting in problem that applications developed at one PaaS cannot be transferred into another PaaS. For standardized Telec