of network abstraction. Classification of these levels of service enabler abstraction defines the framework layers. For instance, Parlay X defines simple Web services that expose highly abstract functionality to external sources. We classify service enablers providing simple functionality to external sources into a simple service layer. Standards such as Parlay and OMA, define rich service enablers that support Parlay X Web services by simplifying access to network resources. We classify service enablers providing rich functionality to simple service enablers into an inter- mediate service layer. The IMS defines network-oriented service enablers that sup- port Parlay and OMA by providing an interface to network functions. We classify service enablers providing richer functionality to intermediate service enablers into a complex service layer. The IMS also provides functional entities that abstract the service and resource- oriented capabilities of the underlying network. We classify these network-related abstractions into a service function layer and resource function layer. The lowest layer of the framework contains the physical network resources. All service layer abstractions (service enablers) offer access to their capabilities using standards-based interfaces. Hence, higher-layer service enablers invoke lower- layer service enablers via their interfaces. Another abstraction that invokes service enablers interfaces are applications. Applications do not offer interfaces to higher layers, but invoke lower-layer service enabler interfaces to provide specific function- ality. Varying levels of applications may be defined based on the service enabler interfaces they invoke. For instance, applications invoking simple service enabler interfaces constitute the simple application layer. Similar to simple service enablers, some applications may invoke intermediate service enabler interfaces. Hence, these applications form part of the simple service layer. In addition, applications invoking complex service enabler inter