 the capabilities of the terminal). Bundling sets of services forms personalized service portfolios for subscribers belonging to a home environment. VHE is further treated in Chapter 15. The standardized OSA interface needs to be secure, independent of vendor-specific solutions and independent of programming languages, operating systems etc. used in the service capabilities. Furthermore, the OSA interface is independent of the location within the home environment where service capabilities are implemented and independent of supported server capabilities in the network. 9.6.3 THE SERVICE CAPABILITY SERVICES (SCS) A kind of bridge between applications and network resources is required. Services and appli- cations negotiate the resources with the control layer over standardized APIs. Resources in Understanding Changing Telecommunications - Building a Successful Telecom Business Application 1 Application 2 Application N Service capability servers Packet-switched domain Network control layer Circuit-switched IP multimedia domain domain Figure 9.6 Bridge between applications and bearer resources the packet, circuit or multimedia domain can (ideally) be negotiated. The bridge is illustrated in Figure 9.6. API is explained in Chapter 3. See more below. The bridge consists of software enablers connected to a network. The original name was service capability services (SCS), which reside in service capability servers. Today it is perhaps common to speak about the more open-ended and wider expression service enablers rather than SCS. SCS constitute the basic set of network-related APIs offered to applications. Network functionality as offered to applications is thus defined as a set of service capability features (SCFs) in the OSA interface. These SCFs reside in service capability servers. The servers provide access to the network capabilities on which the application developers can rely when designing new applications (or enhancements/variants of exist- ing ones). The different features of the different servers can be combi