uch services and applica- tions require enhanced message routing and control in the core stack. As we can see, a potential channel for the Telecom operators to increase their revenue is to offer these functionalities as services to developers for creating such new innovative applications. These developers can belong to not only the select partners of the Telecom operator, but also those involved in creating a variety of long-tail applications [2]. Additionally, due to the IP and telephony networks con- verging, developers can also compose their applications with third-party services available on the IP network. For example, Location and Presence information from Telecom can be clubbed with Google Maps to provide new workforce management solutions for mobile settings [3]. Recognizing the potential, Telecom operators have started investing heavily to redesign their back-end support systems (e.g., billing, provisioning, and network sup- port systems) to address the challenges of providing the user with a unified commu- nication, collaboration and service access experience. However, the core functionalities of location, presence, call control, and SO on were SO far used only internally by the carrier operator's core services (e.g., calls). As such, they were not accessible outside the network, and not easily integrable and interoperable with third-party services. Toward alleviating these problems, there has been a concerted effort toward the creation of a blueprint for a common service delivery platform (SDP) over the past few years. Next-generation SDP* is an architectural solution that enables the reuse of service components trapped in "vertical service silos" by adopting a horizontal layered approach. There are capabilities beyond network enablers that need to be exposed through the operators SDP-these include mobility, operation support system-billing support system (OSS-BSS), functions such as billing and provision- ing, subscriber profiles, QoS attributes of network elements, as well as profiles of devices supp