independent service components such as location, content downloading, device management and presence. Understanding Changing Telecommunications - Building a Successful Telecom Business Other new workgroups include requirements, architecture and interoperability. The requirements group identifies and specifies technical requirements for the development of mobile services. The architecture group defines the overall OMA system architec- ture including evolution, integration and maintenance. The interoperability group ensures end-to-end interoperability. See http://www.openmobilealliance.org/docs. The sections on XML for business documents and web services and the section on MExE (mobile execution environment = WAP and Java) in this chapter are also part of this dynamic subject area. Regarding XML see also Chapter 3, Section 3.11.2 A number of support services exist in the service network to aid the proper operation of the IP network that connects all the servers. Service networks are initially deployed together with mobile systems. 9.5 TERMINOLOGY For the purposes of this book, the definitions and abbreviations given below apply: Home environment: actor responsible for overall provision of services to users. HE-VASP: home environment value-added service provider. This is a VASP that has an agreement with the home environment to provide services. Personal service environment: contains personalized information defining how sub- scribed services are provided and presented to the user. Service capabilities: bearers defined by parameters, and/or mechanisms needed to realize services. These are within networks and under network control. Service capability feature: functionality offered by service capabilities that are acces- sible via the standardized OSA interface. Service capability server: functional entity providing OSA interfaces to an application. Value-added service provider: provides services other than basic telecommunications service for which additional charges may be incurred. Virtual home environment (VHE): c