ce composition environment designed bottom-up to support rapid integration of Telecom function- alities with converged services. Its design is based on its own Telecom Service Reference, Encapsulation, and Coordination (T-Rec) "Proxy" model. This enables developers to seamlessly incorporate Telecom functionality and apply various coordi- nation rules. Further, SewNet provides an eclipse-based* service composition environment based on the T-Rec model. SewNet can be used by different categories of developers, including Java, BPEL, and HTML/JavaScript programmers. It is important to note that although we focus on Telecom here, the T-Rec proxy model is generic and applicable to third-party services available on the Web. 1.2.1 Problem Illustration and Motivation We illustrate the problem with respect to the component-oriented diagram of a service that utilizes Telecom functionality, as shown in Figure 1.1. In general, such an application can be broken into two major blocks. First, there are Telecom blocks (represented as black rectangular boxes in the figure) that invoke a Telecom network functionality (e.g., invoking the location service or capabilities like SMS, Third- Party Call Control). The others are non-Telecom blocks, where the developers can Location 3rd party Receive SMS service Send SMS Presence Start App logic App logic UI construct Figure 1.1 Model of a Telecom service. * http://www.eclipse.org Service Delivery Platforms embed various constructs (depicted by gray hexagonal boxes in the figure). For example, in a workforce management solution, these blocks can contain logic for scheduling agents on the basis of Location and Presence information provided by Telecom operator. Alternatively, these blocks can be user interface (UI) constructs, for instance, those enabled by various Ajax-based platforms. Finally, the non- Telecom blocks can also be invocation points for orchestration with third-party services available over the Web. Also, as the figure shows, to bind these Telecom and non-Telecom blocks, specif